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  • 2020-2022
  • 1990-1994  (737)
  • 1985-1989
  • 1993  (386)
  • 1992  (351)
  • Genetics  (474)
  • crystal structure  (263)
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  • 2020-2022
  • 1990-1994  (737)
  • 1985-1989
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  • 1
    ISSN: 1572-8862
    Keywords: Platinum ; ruthenium ; crystal structure ; heteronuclear cluster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract From the reaction of Ru(CO)5 and Pt(COD)2, COD = 1, 5-cyclooctadiene, the new platinum-ruthenium heteronuclear cluster complex Pt2Ru4(CO)18,1, was obtained in 60% yield.1 has a folded ladder-like structure with alternating pairs of ruthenium atoms and platinum atoms. The cluster of1 can be split to yield the known compound PtRu2(CO)8(η2-dppe),2, (54% yield) by reaction with 1, 2-bis(diphenylphosphino)ethane, dppe, at 25°C. When1 was treated with excess dppe at 40°C, thebis-diphos compound3, PtRu2(CO)6(μ-η2-dppe)2 was obtained (39% yield). Under the similar reaction conditions,2 was converted to3 in 44% yield. All these complexes were characterized by single crystal X-ray diffraction analyses. Compounds2 and3 both contain a triangular cluster of one platinum and two ruthenium atoms, but in2 the bidentate ligand, dppe, chelates the platinum atom and in3 the two dppe ligands bridge the two Pt-Ru metal-metal bonds. Crystal data for1: space group C2/c,a=12.542(2)Å,b=15.350(4)Å,c=15.252(3)Å, β=105.32(2)°,Z=4, 2192 reflections,R=0.025. For2: space group P21/c,a=14.351(2)Å,b=13.486(3)Å,c=19.218(3)Å, β=108.48(1)°,Z=4, 3029 reflections,R=0.027. For3: space group P21/c,a=18.836(6)Å,b=15.559(5)Å,c=23.259(7)Å, β=111.26(2)°,Z=4, 4204 reflections,R=0.038.
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  • 2
    ISSN: 1572-8862
    Keywords: Tungsten ; chloride ; hexatungsten ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The hexanuclear tungsten cluster complex [W6(μ3-Cl)8Cl6]2−,1 was isolated as a salt of the cation (MeO2CCH2)2N(H)CH2CH2N(CH2CO2Me)2+, EDTEH+, by crystallization from methanol solvent of the product obtained from the reaction of (H3O)2[W6(μ3-Cl)8Cl3] with the disodium salt of ethylenediaminetetraacetic acid. The compound was charcterized by single-crystal X-ray diffraction analysis. The cluster anion contains an octahedral arrangement of six tungsten atoms with chloride ligands bridging the eight triangular faces of the cluster and one chloride ligand terminally coordinated to each of the six tungsten atoms. The cation (EDTEH)+ achieves its positive charge by protonation of one of the nitrogen atoms. Crystal data: space group = P21/a,a=10.689(2) Å,b=22.931(6) Å,c=12.093(3) Å, β=98.41(2)°,Z=2, 2476 reflections,R=0.028.
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  • 3
    ISSN: 1572-8862
    Keywords: Molybdenum ; acetate, carboxylate ; hexamolybdenum ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The hexamolybdenum cluster complex [Mo6(μ3-Cl)8(O2CMe)6]2−, 1 was isolated as the Bu4N+ salt in 71% yield from the reaction of (Bu4N)2[Mo6(μ3-Cl)8Cl6] with AgO2CMe in CH2Cl2 solvent. The compound was characterized by single crystal X-ray diffraction analysis. The cluster contains an octahedral arrangement of six molybdenum atoms with eight chloride ligands bridging the eight trianglar faces and six carboxylate ligands terminally coordinated through one oxygen atom to each of the six molybdenum atoms. Crystal data: space group =P21/n,a=10.713(3)Å,b=14.43(1)Å,c=21.919(4)Å, β=94.37(2)°,Z=2, 1965 reflections,R=0.036.
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  • 4
    ISSN: 1572-8862
    Keywords: Vanadium ; phenylhydrazine ; nitrogenase ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Addition of phenylhydrazine to a mixture of VCl3 · THF/N,N-propyl-bis (salicyladimine) and sodium hydride yielded a trinuclear vanadium complex, V3(μ3-O)(μ-Cl)Cl6(μ-η1-η1PhNHNH2)2(PhNHN H2)2(THF), containing two bridging and two terminal phenylhydrazine ligands. The product has been crystallographically characterized (P21/n, a=12.949(2) Å,b=24.061(4) Å,c=22.504(4) Å, β=107.22(1) deg.,V=6697(2) Å3 withZ=4) and was found to contain the first example of bridging monosubstituted hydrazine (phenylhydrazine) ligands.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymers and the environment 1 (1993), S. 65-80 
    ISSN: 1572-8900
    Keywords: Biodegradable plastic ; microbial degradation ; bacterial poly(d-(−)-3-hydroxybutyrate) ; crystal structure ; physiological behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract As one of a series of studies concerning the relationship between the higher-order structure and the biodegradability of a biodegradable plastic, the effects of the crystal structure of the plastic on microbial degradation were investigated. Bacterial poly(d-(−)-3-hydroxybutyrate) (PHB) films which had a wide range of crystallinity were prepared by the melt-quenching method. Results of the microbial degradation indicated that the development of crystallinity evidently depressed the microbial degradability. From scanning electron microscopy (SEM) observations, it is suggested that the microbial degradation proceeded in at least two manners. One was preferential degradation of the amorphous region leaving the crystalline lamellae intact, which was considered to be a homogeneous enzymatic degradation over the surface. The other was nonpreferential spherical degradation on the surface. The SEMs indicate that the spherical holes were the result of colonization by degrading bacteria. The holes varied in size and number with the change of crystal structure. Therefore, it is considered that the crystal structure of PHB also influenced the physiological behavior of the degrading bacteria on the PHB surface.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1437-160X
    Keywords: Systemic lupus erythematosus ; HLA-DP ; Ro (SS-A) autoantibodies ; La (SS-B) autoantibodies ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated the association of HLA-DPB1 alleles with the occurrence of autoantibodies against Ro (SS-A) or La (SS-B) using recombinant 52kD-Ro, 60 kD-Ro and La proteins in 177 German patients with systemic lupus erythematosus (SLE). A significant increase in the frequency of DPB1 *0101 is observed in SLE patients compared to healthy controls (P corr.〈0.004). Antibodies against 52 kD-Ro, 60 kD-Ro and La are tested by ELISA and are found with a frequency of 25.4%, 33.9% and 17.5% in the patients, respectively. An association with HLA-DPB1 *0101 is observed for antibodies against La (P〈0.01) and 52 kD-Ro (P〈0.01), but not for 60 kD-Ro in the absence of La/52 kD-Ro. Since there is a strong linkage disequilibrium between DPB1 *0101 and DR3 in the normal population and in SLE patients, and since there is an association between DR3 and SLE, as well as between DR3 and the occurrence of recombinant Ro/La antibodies in SLE patients, we investigated whether DPB1 *0101 is associated per se or via linkage disequilibrium with DR3. DPB1 *0101 in the absence of DR3 is not more common in patients than in controls and not in patients with autoantibodies to Ro and La than without antoantibodies. We conclude that there is no evidence for a direct involvement of DPB1 *0101 in the production of Ro/La autoantibodies in SLE patients.
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  • 7
    ISSN: 1432-1440
    Keywords: Hereditary ataxias ; Friedreich's ataxia ; Genetics ; FRDA locus ; Chromosome 9
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The clinical features of Friedreich's ataxia are described and reevaluated in a group of 14 German patients from 9 independent families. In contrast to previous studies, demonstration of linkage to the Friedreich's ataxia locus (FRDA) on chromosome 9p allowed confirmation of the genetic homogeneity of the disease in the patients under study. Marked variability within families was observed for age of onset of the disease (4–24 years) and for age of becoming wheelchair bound (17–37 years). Electrocardiographic changes were present in all and echocardiographic changes in 50% of the patients. Pathological changes of visual evoked potentials were detected in only 50% of the patients while brainstem auditory evoked potentials and somatosensory evoked potentials were always abnormal.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 240 (1993), S. 151-155 
    ISSN: 1432-1459
    Keywords: Genetics ; Complex partial seizures ; Waking and sleep EEGs ; Siblings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Waking and sleep EEGs were recorded in 29 siblings of 19 patients with complex partial seizures. At least 1 sibling with epileptic activity (EA) was found for 36.8% of the patients. Taking the 29 siblings as a basis, in 7 EA was recorded. Most EA was seen during sleep in stage C (29%). More EA was recorded in female siblings (28% :18%) and in siblings of female patients (56% :20%). All EA was seen in the age range 5–14 years. Siblings with occipital theta-delta activity with a generalization tendency showed more EA (59%) than those without this pattern (8%). Of the siblings of patients with generalized EA 50% showed EA, but only 25% of those of patients with localized EEG patterns.
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  • 9
    ISSN: 1432-0428
    Keywords: Genetics ; DNA polymorphism ; glucose ; phosphorylation ; glycolysis ; chromosome 2 ; insulin resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Type 2 (non-insulin-dependent) diabetes mellitus is characterized by decreased levels of glucose 6-phosphate in skeletal muscle. It has been suggested that the lower concentrations of glucose 6-phosphate contribute to the defect in glucose metabolism noted in muscle tissue of subjects with Type 2 diabetes or subjects at increased risk of developing Type 2 diabetes. Lower levels of glucose 6-phosphate could be due to a defect in glucose uptake, or phosphorylation, or both. Hexokinase II is the isozyme of hexokinase that is expressed in skeletal muscle and is responsible for catalysing the phosphorylation of glucose in this tissue. The recent demonstration that mutations in another member of this family of glucose phosphorylating enzymes, glucokinase, can lead to the development of Type 2 diabetes prompted us to begin to examine the possible role of hexokinase II in the development of this genetically heterogeneous disorder. As a first step, we have cloned the human hexokinase II gene (HK2) and mapped it to human chromosome 2, band p13.1, by fluorescence in situ hybridization to metaphase chromosomes. In addition, we have identified and characterized a simple tandem repeat DNA polymorphism in HK2 and used this DNA polymorphism to localize this gene within the genetic linkage map of chromosome 2.
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  • 10
    ISSN: 1432-0428
    Keywords: Genetics ; Type 2 (non-insulin-dependent) diabetes mellitus ; HLA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Epidemiologic data suggest that a parental history of Type 2 (non-insulin-dependent) diabetes mellitus increases the risk of Type 1 (insulin-dependent) diabetes in siblings of a Type 1 diabetes proband. This increase in risk is consistent with a shared genetic susceptibility between Type 1 and Type 2 diabetes. We have previously reported evidence that HLA-DR4-linked factors may represent a homogeneous subset of diabetes susceptibility. First, HLA-DR4 frequency was higher in Type 1 diabetic study subjects with a Type 2 diabetic parent than in Type 1 diabetic subjects whose parents were not diabetic. Second, a DR4-haplotype was transmitted from the Type 2 diabetic parent to the Type 1 offspring more often than expected. These data are consistent with the hypothesis that families with a Type 2 diabetic parent and Type 1 diabetic child, heavily determined by HLA-DR4 linked factors, may represent a homogeneous subset of diabetes susceptibility. In this report, we further explore the relationship between the high-risk HLA antigen (HLA-DR4) in study subjects with differing glycaemic status (National Diabetes Data Group criteria). In this community-based study, we find evidence that HLA-DR4 is increased in study subjects with Type 2 diabetes and may be a marker for Type 2 diabetes susceptibility.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 152 (1993), S. 467-468 
    ISSN: 1432-1076
    Keywords: Hirschsprung disease ; Familial occurrence ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Hirschsprung disease (HD) is genetically heterogeneous with approximately 4% familial occurrence. The recurrence risk is higher in patients with severe involvement. We describe the transmission of histotopochemically proven HD from a father with long aganglionic segment disease to a son with ultrashort segment disease. This observation suggests that the length of involvement in HD is related to the variable expression of the gene defect. It also suggests autosomal dominant inheritance of HD.
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  • 12
    ISSN: 1432-1076
    Keywords: Androgen ; Receptor ; Genetics ; Mutations ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Androgen insensitivity syndromes represent one cause of human male pseudohermaphroditism related to defects in the androgen receptor. The formation of a biologically active androgen receptor complex with testosterone and 5α-dihydrotestosterone is required for normal androgen action during fetal development and fifferentiation of the internal accessory sex glands and external genitalia. Cloning of the human androgen receptor complementary DNA and genetic screening of human subjects with the clinical and biochemical features of androgen insensitivity using the polymerase chain reaction, denaturing gradient gel electrophoresis and nucleotide sequencing techniques have led to the identification of molecular defects in the androgen receptor. The complexity of phenotypic presentation by affected subjects with the complete or partial forms of androgen insensitivity is represented by the heterogeneity of androgen receptor gene mutations which include deletions and point mutations, with the latter causing, inappropriate splicing of RNA, premature termination of transcription and amino acid substitutions. The naturally occurring mutations in the androgen receptor of subjects with androgen insensitivity represent a base upon which we can increase our understanding of the structure and function of the androgen receptor in normal physiology, and disease.
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  • 13
    ISSN: 1432-2072
    Keywords: Morphine ; Behavioral activity ; Analgesia ; Rat ; Self-administration ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of the current study was to investigate genetic differences between two inbred strains of rats, Fisher-344 (F344/N) and Wistar Albino Glaxo (WAG/GSto), in a number of drug-naive and drug-related behaviors, including oral and intravenous morphine self-administration. F344/N and WAG/GSto rats differed in drug-naive behaviors such as nociception, rearing and sensitivity to lick suppression tests but did not differ in locomotor activity, ambulation or grooming behavior. F344/N rats were less sensitive to thermal stimuli as measured via tail-flick response, and more sensitive to the suppressive effects of intermittent shock in a lick suppression test. The F344/N rats demonstrated a significantly greater amount of rearing in open field tests but did not differ from WAG/GSto rats in locomotor activity, ambulation or grooming behavior. In addition to the behavioral results, naive F344/N and WAG/GSto rats were found to differ in μ and α2 receptor concentrations (F344/N〉WAG/GSto) and in 5HT2 and D2 affinity constants (WAG/GSto〉F344/N). These two inbred rat strains also differed in drug-related behaviors. F344/N rats showed significantly greater depression of locomotor activity at morphine 3 mg/kg than WAG/GSto rats. In addition, F344/N rats consumed significantly greater amounts of morphine in a two-bottle choice procedure and morphine maintained significantly greater amounts of behavior during intravenous self-administration sessions. Importantly, drug maintained behavior was significantly greater than with vehicle only in the F344/N rats during operant self-administration sessions.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 243 (1993), S. 143-149 
    ISSN: 1433-8491
    Keywords: Genetics ; Linkage ; Psychiatric disorders ; Genetic epidemiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Linkage analysis has been successful in identifying the genetic basis of numerous Mendelian diseases. These successes were due in part to the rapid developments in molecular biology, which have yielded a plethora of informative genetic markers. Although there is strong evidence that the manifestation of schizophrenia and bipolar affective disorders is controlled by genes, no evidence for linkage has been established. For psychiatric disorders, the most important limiting factor is likely to be the lack of single loci with very large effects that occur with any relevant frequency. The difficulties of linkage studies in psychiatric disorders are discussed with reference to non-psychiatric genetic diseases for which linkage to genetic markers has been successful. Recommendations for collecting information to clarify the patterns of transmission of the psychiatric disorders are described.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 243 (1993), S. 131-142 
    ISSN: 1433-8491
    Keywords: Genetics ; Nosology ; Methodology ; Linkage analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Statistical procedures and molecular genetic techniques have attained a fine degree of resolution. Their ability to find disease genes has revolutionized medicine and raised hopes for breakthroughs in psychiatry. However, such breakthroughs may require an equally discriminating nosology. A psychiatric genetic nosology seeks to classify patients into categories that correspond to distinct genetic entities by addressing the problem of diagnostic accuracy: the degree to which a diagnosis correctly classifies people with and without a putative genetic illness. We review methods that deal with misclassification in genetic studies. These are clinical and epidemiological approaches that deal directly with how to define the observable manifestation of a putative genotype. We discuss two groups of methods: those that use known phenotypes and those that design new phenotypes.
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  • 16
    ISSN: 1572-9001
    Keywords: Atomic displacement ; molecular motion ; vibrational analysis ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Atomic displacement parameters determined from a single-crystal X-ray-diffraction study on K2Ru(SO4)2 * 6H2O are analyzed in the molecular mean field approximation. The motion of SO2 2− can be described with a rigid-body model, whereas for [Ru(H2O)6]2+ internal stretching motion and coupling between stretching motion and overall translation are found to be necessary for explaining the observed atomic displacement parameters. Frequencies and force constants of internal motion are not significantly affected by such couplings. K2Ru(SO4)2 * 6H2O crystallizes in the monoclinic space groupP21/c (No. 14), witha = 6.1211(7)Å,b = 12.226(2) Å,c = 8.916(2)Å,β = 105.11(1)°,Z = 2 at 160 K anda = 6.1402(7)Å,b = 12.274(2)Å,c = 8.957(1)Å,β = 105.25(1)°,Z = 2 at 295 K. The structure was refined to a finalR(F) of 0.017 at 160 K and of 0.019 at 295 K for 1438 and 1299 observed reflections withF 0 〉 6σ(F0) and sin θ/λ 〉 0.617 Å1−.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Molecular engineering 3 (1993), S. 43-59 
    ISSN: 1572-8951
    Keywords: Heteropolymolybdates ; heteropolytungstates ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The chemistry of polynuclear oxometalate anions is dominated by molybdenum and tungsten in their highest oxidation state. During the past twenty years this class of compounds has attracted much attention because of their variable applications, e.g. as reagents in analytical procedures, as industrial catalysts and as potential anticancer drugs. In order to obtain model systems for the investigation of the catalytic activity of heteropolyanions we have synthesized and structurally characterized some organo derivatives of polyoxoanions. We secondly focus on Sb(III) and Bi(III) heteropolytungstates to examine the important influence of the unshared electron pair on the resulting structures and properties. Some of these compounds may be regarded as supramolecular aggregates showing inclusion phenomena. In 9 two [SbW9O33]9− anions are linked by a set of six sodium ions forming a nearly planar hexagon. The sodium ions are enveloped by an oxygen cage formed by terminal oxygen atoms of the polyanions and by water molecules. Furthermore, the four anions [Sb2W22O74(OH)2]12−, [Sb2W20Fe2O70(H2O)6]8−, [Sb2W20Co2O70(H2O)6]10− and [Bi2W20Fe2O68(OH)2(H2O)6]6− (in10, 11, 12, 13) may be regarded as transition metal complexes of novel [Sb2W20O70]14− or [Bi2W20O70]14− anions which are serving as ligands. The octahedral coordination sphere of each transition metal is formed by three oxygen atoms of the anion and completed by three water molecules. The Sb(III) heteropolyanion, [Na2Sb8W36O132(H2O)4]22− in (14) includes two sodium and four antimony ions besides four water molecules. Each anion consists of four β-B-SbW9-Keggin fragments linked together by four SbO4-groups, incorporating two sodium and four water molecules effecting an additional connection of the subunits.
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  • 18
    ISSN: 1572-9001
    Keywords: Cobaltocene ; molecular geometry ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molecular and crystal structures of the monoclinic modification of cobaltocene Cp2Co (P21/n, Z=2) was determined at 100 K and 297 K with new sets of X-ray diffraction data (MoKα radiation, 3995 and 6534 reflections, refinement toR = 0.026 and 0.030 using 1061 and 1299 independent observable reflections, respectively). At 297 K the structure is disordered (similar to the isomorphous ferrocene and nickelocene) with two distinct orientations of the ring, differing in occupancy factors (80% and 20%) and by a rotation angle in the ring plane of approximately 34°. Just as for nickelocene but in contrast to ferrocene, no sharp phase transition was found on cooling Cp2Co to 100 K, but an essential ordering of the Cp-ring position was detected with a decrease of the contribution of the second minor orientation to nearly 10%. On the basis of a careful analysis of the molecular geometry, crystal packing, and anisotropic atomic displacement parameters, a dynamic temperature-dependent nature of the disorder in Cp2Co is assumed.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 86 (1993), S. 333-338 
    ISSN: 1432-2242
    Keywords: Genetics ; Rice ; Salinity ; Tolerance ; Na-Kratio ; Diallel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genetics of salinity tolerance in rice was investigated by a nine-parent complete diallel including reciprocals. Test materials involved susceptible (IR28, IR29, and MI-48), moderately tolerant (IR4595-4-1-13, IR9884-54-3-1E-P1, and IR10206-29-2-1), and tolerant (“Nona Bokra”, “Pokkali”, and SR26B) parents. Twoweek-old seedlings were grown in a salinized (EC = 12 dS/m) culture solution for 19 days under controlled conditions in the IRRI phytotron. Typical characteristics of salinity tolerance in rice were found to be Na+ exclusion and an increased absorption of K+ to maintain a good Na-K balance in the shoot. Genetic component analysis (GCA) revealed that a low Na-K ratio is governed by both additive and dominance gene effects. The trait exhibited overdominance, and two groups of genes were detected. Environmental effects were large, and the heritability of the trait was low. Our findings suggest that when breeding for salt tolerance, selection must be done in a later generation and under controlled conditions in order to minimize environmental effects. Modified bulk and single-seed descent would be the suitable breeding methods. Combining ability analysis revealed that both GCA and specific combining ability (SCA) effects were important in the genetics of salt tolerance. Moderately tolerant parents — e.g., IR4595-4-1-13 and IR9884-54-3-1E-P1 — were the best general combiners. Most of the best combinations had susceptible parents crossed either to moderate or tolerant parents. The presence of reciprocal effects among crosses necessitates the use of susceptible parents as males in hybridization programs. Large heterotic effects suggest the potential of hybrid rice for salt-affected lands.
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  • 20
    ISSN: 1432-2242
    Keywords: Genetics ; Disease ; Mapping ; Breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Molecular markers at 103 loci were used to identify the location of quantitative sources of resistance to Exserohilum turcicum in 150 F2∶3 lines of a B52/Mo17 maize population. Host-plant response was measured in terms of the average number of lesions per leaf, the average percent leaf tissue diseased (severity), and the average size of lesions. The location of quantitative trait loci were compared with three loci having known qualitative effects, namely Ht1, Ht2 and bx1. Chromosomal regions containing the Ht1 and Ht2 loci showed a small contribution in determining lesion size, even though alleles with dominant, qualitative effects at these loci have never been reported in either inbred parent. Similar effects were not observed for the number of lesions or for disease severity. Likewise, some contribution was observed for chromosomal regions encompassing the bx1 locus in determining lesion size but not the number of lesions or disease severity. Overall the contribution of loci in the vicinity of Ht1, Ht2 and bx1 was small relative to variation attributable to loci with quantitative effects identified in this study. Molecular-marker-facilitated mapping concurred with previous reciprocal translocation mapping studies on the importance of chromosomes 3, 5 and 7, despite the fact that these studies utilized diverse sources of resistant germplasm.
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  • 21
    ISSN: 1573-9171
    Keywords: iron(II) and ruthenium(II) complexes ; synthesis ; carbonyl, cyclopentadienyl, benzoate ligands ; crystal structure ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Complexes of Fe(II) and Ru(II) of the general formula Cp(OC)2MOC(O)C6H4X-p, where M=Fe, X=H, F (1, 2) or M=Ru, X=H, F (3, 4) have been prepared by reactingp-XC6H4COOAg with [CpFe(CO)2]2 or CpRu(CO)2I. The crystal structures of complexes1–3 have been determined using X-ray diffraction. Compounds1 and3 are isomorphous. The COO group in1–3 is coordinated as a monodentate ligand. As the latter and the CO ligands are electronically non-equivalent, the coordination of the Cp ligand to the metal is slightly asymmetric.
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  • 22
    ISSN: 1573-9171
    Keywords: synthesis ; crystal structure ; azepinethiones ; trimethylsilyl derivative
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title compounds were prepared and X-ray analysis was performed (R = 0.064 and 0.035 for 1309 and 1637 reflections, respectively). In the former the intramolecular S→Si coordination interactions are absent and the Si atom has undistorted tetrahedral coordination with an S...Si distance of 4.034 Å. Crystals of the latter are built of centrosymmetric dimeric H-complexes (S...H(N) 2.58 Å, the S...HN angle 168°).
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  • 23
    ISSN: 1573-9171
    Keywords: peroxosolvates ; potassium fluoride ; monoperoxosolvate ; thermal stability ; crystal structure ; hydrogen bond
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Potassium fluoride peroxosolvate KF-H2O2 was obtained upon action of a 30% aqueous solution of hydrogen peroxide on solid potassium fluoride dihydrate. As compared to other peroxosolvates, KF-H2O2 is characterized by the highest thermal stability: the decomposition rate constantk 1, at 120°C is 1.4 10−3 min−1, the enthalpy of H2O2 addition to KF is 8.1 kcal/ mol. The correlation between the high stability of KF-H2O2 and the absence of catalytic properties of KF towards H2O2, and the formation of strong intermolecular O-H...F and intramolecular O-H...O hydrogen bonds in the crystal is discussed.
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  • 24
    ISSN: 1573-9171
    Keywords: synthesis ; crystal structure ; pentacoordinated silicon ; chelate cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The X-ray diffraction structural study of the (N-Si)-chelate of 2-(chlorodimethyl-silylmethylthio)-1-pyrroline was carried out (R = 0.033 for 1894 reflections). The Si atom has a somewhat distorted trigonal bipyramidal coordination with the Cl and N atoms in axial positions. The Si-Cl and Si-N distances (2.423(1) and 1.945(1) Å) belong, respectively, to the longest and shortest known Si-Cl and Si-N distances in pentacoordinated silicon derivatives with an axial N-Si-Cl moiety.
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  • 25
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    Russian chemical bulletin 42 (1993), S. 1149-1151 
    ISSN: 1573-9171
    Keywords: Pt(dddt)2 ; organic conductors ; 5,6-dihydro-1,4-dithiin-2,3-dithiolate((dddt)2−) ; sulfur-containing platinum complexes ; crystal structure ; synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A neutral metal complex, [Pt(dddt)2]° (1), has been obtained by oxidation of the [Pt(dddt)2]− anion with excess (Bu4N)AuBr4 in nitrobenzene. Crystallographic data for 1∶a=17.854(9) Å,b=18.409(9) Å,c=4.717(5) Å, γ=68.83(2)°, space group P21/n,Z=4,d calc=2.55 g/cm3. In1 two independent centrosymmetric [Pt(dddt)2]° molecules are packed in stacks that form layers parallel to the (110) plane. The molecules of1 in the layers have shortened S...S contacts 3.491(9) Å, and 3.594(10) Å. The average bond lengths Pt-S 2.242(7) Å, S-C 1.71(2) Å and C=C 1.40(3) Å, together with the square-planar coordination of Pt in PtS4, suggest considerable conjugation in the metal cycles.
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  • 26
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    Russian chemical bulletin 42 (1993), S. 1415-1417 
    ISSN: 1573-9171
    Keywords: vanadatrane ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An X-ray diffraction study of a substituted vanadatrane-1-one (space groupPna21,R= 0.019 for 1394 reflections, the absolute structure was determined) showed that the geometry of its atrane framework is similar to that of the Si- and Ge-analogs. The bond lengths are: V=O, 1.614(2) Å; V←N, 2.329(2) Å; V-O, 1.800–1.806(2) Å. The deviation of the V atom having distorted trigonal bipyramidal coordination from the equatorial plane of the O atoms is 0.35 Å, the 0=V←N bond angle is 179.4(1)°.
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  • 27
    ISSN: 1573-9171
    Keywords: titanasilanes ; titanasilazanes ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An X-ray structural study of two titanium-containing organosilicon compounds, (Me3Si)3SiTi(NEt2)3 (1) and ClTi[N(SiMe3)2]3 (2), has been performed. The conformation of molecule1 in a crystal is staggered (approximate inherentC 3 symmetry), the Ti-Si and Ti-N bond lengths are 2.671(2) and 1.874–1.890(5) Å, respectively. A crystal of1 consists of one type of enantiomers (the space group is P41212; the absolute configuration has been determined). The structure of2 studied previously has been refined to the value of R=0.029 on the basis of 3442 reflections (the absolute structure has been determined), the Ti-Cl and Ti-N bond lengths are 2.260(1) and 1.926(1) Å, respectively. The strong distortions in the symmetry of the valence environment of the N atoms in the molecules of1, 2, and related structures are caused by electronic effects, in which the conformation of the relevant molecular fragments plays a determining role.
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  • 28
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    Protoplasma 176 (1993), S. 53-63 
    ISSN: 1615-6102
    Keywords: Acetabularia acetabulum ; Gamete release ; Mating efficiency ; Mating physiology ; Gamete half-life ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have improved zygote recovery 11–1,000 fold by optimizing the physiology of gamete release and mating inAcetabularia acetabulum. Gamete release was affected by agar purity, concentration, and volume/gametangial pair. Cold pre-treatment of gametangia (14–30 d at 10°C in the dark) synchronized subsequent gamete release at 21°C in the light. Cold pre-treatment was nearly twice as effective in synchronizing subsequent gamete release when intact, gametangia-bearing caps rather than isolated gametangia were pretreated. Synchronizing gamete release doubled mating efficiency. In a wild-type laboratory strain ofA. acetabulum, there were 1,561±207 gametes/gametangium which had half-lives of 14.5 d in 0.1% seawater-agar. We recovered 48–93% of the expected numbers of zygotes from a mass mating of 8 to 1,226 gametangia and 11–128% of the expected numbers of zygotes from mating single gametangial pairs: the large range in the calculated mating efficiency may be attributable to the variation in the numbers of gametes made per gametangium. Zygote recovery from single gametangial pairs was highly dependent on the volume of mating matrix. In addition, most zygotes recovered were unattached to any other zygotes in the subsequent generation (〉 95% single cells from matings of 1–500 gametangial pairs). Our improvements in mating conditions and zygote recovery (1) have facilitated cell manipulation and culture ofA. acetabulum in the laboratory; and (2) have made controlled crosses for selection and genetic analysis of mutants feasible. These advances have removed a major barrier to genetic analysis of development inAcetabularia.
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  • 29
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    Sexuality and disability 11 (1993), S. 221-228 
    ISSN: 1573-6717
    Keywords: Genetics ; disability ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
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  • 30
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    Colloid & polymer science 271 (1993), S. 50-55 
    ISSN: 1435-1536
    Keywords: Polytetrafluoroethylene ; copolymer ; crystal structure ; chain folding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Molecular-mechanics calculations are performed on model folds proposed in the literature for single crystals of polytetrafluoroethylene crystallized in the phase stable below 19°C, in order to evaluate how they are modified when a fluorine atom is substituted by a bulky group, as occurs in fluorinated copolymers of tetrafluoroethylene. Only intramolecular effects are taken into account (isolated-chain model). An exhaustive analysis has been carried out of tetrafluoroethylene-hexafluoropropylene copolymer. Moreover, the lower energy folds found for such a copolymer have been examined for copolymers with chlorotrifluoroethylene and perfluoroalkylvinylethers, as comonomers. Our calculations show that all the considered comonomers can be arranged in the model folds proposed for the homopolymer, according to the imposed geometric constraints.
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  • 31
    ISSN: 0887-3585
    Keywords: thrombin ; bifunctional inhibitor ; crystal structure ; hirutonis ; drugdesing ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The crystal structure of the complexes of hirutonin-2 and hirutonin-6 with human α-thrombin have been solved and refined to R-factors of 0.169 (2.0 Å resolution) and 0.162 (201Å), respectively. Hirutonins belong to a family of bifunctional inhibitors bearing a noncleavable moiety mimicking the scissile bond. Hirutonin-2 is an analog of (D)Phe-Pro-Arg-Gly-hirudin49-65; hirutonin-6 has the same N-terminal tripeptide connected to a shortened fibrinogen exosite-binding part by a short, non-peptidyl linker. The hirutonin-6 molecule is well defined in the electron density with the exception of the C-terminal Leu-h61. The linker follows near the bottom of the canyon connecting the active site with the exosite, forms a short antiparallel β-sheet-like arrangement with Leu-40-Leu41 and makes van der Waals contacts with Glu39-Leu40-Leu41 of thrombin. In the thrombin-hirutonin-2 complex, the N- and C-terminal parts of the inhibitor are well or dered (except the C-terminal Gln-h65) while the central portion of the linker is partially disordered. The glycine analog in the P1′ position of hirutonin-2 assumes a conformation similar to that of the canonical form (Bode and Huber (1992) Eur. J. Biochem. 204 : 433-451) and supports the identification of the S1′ site as restricted by His57, Trp60D, Lys60F, and the Cys42-Cys58 disulfide bridge. The carbonyl oxygen of the P1 arginine residue is located in the oxyanion hole formed by the NH groups of Gly193 and Ser195, while the carbonyl carbon is positioned within a short distance, 2.8 Å, from the Oγ of Ser195. This resembles the conformation of the substrate-like inhibitors bound to other serine proteases. The N-terminal (D)Phe-pro-Arg fragment common to both inhibitors binds to thrombin in a fashion very similar to that of other inhibitors having this motif. The binding of the C-terminus of hirutonins to the fibrinogen-binding exosite is similar to that observed in hirudin and hirulog complexes. © 1993 Wiley-Liss, Inc.
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  • 32
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    Proteins: Structure, Function, and Genetics 16 (1993), S. 205-213 
    ISSN: 0887-3585
    Keywords: calcium binding ; crystal structure ; protein stability ; site-directed mutagenesis ; subtilisin ; X-ray crystallography ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A version of subtilisin BPN′ lacking the high affinity calcium site (site A) has been produced through genetic engineering methods, and its crystal structure refined at 1.8 Å resolution. This protein and the corresponding version containing the calcium A site are describedand compared. The deletion of residues 75-83 was made in the context of four site-specific replacements previously shown to stabilize subtilisin. The helix that in wild type is interrupted by the calcium binding loop, is continuous in the deletion mutant, with normal geometry. A few residues adjacent to the loop, principally those that were involved in calcium coordination, are repositioned and/or destabilized by the deletion. Because refolding is greatly facilitated by the absence of the Caloop, this proteinoffers a new vehicle for analysis and dissection of the folding reaction. This is among the largest internal changes to a protein to be described at atomic resolution. © Wiley-Liss, Inc.
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  • 33
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    Primates 34 (1993), S. 333-346 
    ISSN: 0032-8332
    Keywords: Genetics ; Pedigrees ; Molecular evolution ; Pan ; Hylobates ; Macaca ; DNA sequences ; Microsatellite loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using DNA amplified from shed or plucked hair follicles it is now possible to genotype individual primates at many nuclear and mitochondrial gene loci. Sequence specific primers and the polymerase chain reaction permit the rapid production of sufficient DNA from a single hair for numerous analyses. The direct sequencing of relatively conservative mtDNA sequences like cytochromeb is proving useful in establishing species and subspecies-level relationships. More variable sequences (e.g. the mtDNA control region or D-loop) are useful at the population and social community levels. Paternity exclusion, pedigree relationships, and community structure can be determined using simple sequence length polymorphisms (SSLPs) of multiple hypervariable nuclear microsatellite or simple sequence repeat (SSR) loci. Studies involving captive and free-ranging chimpanzees, gibbons, and macaques illustrate the resolving power of these new non-invasive molecular genetic genotyping techniques.
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  • 34
    ISSN: 1573-1111
    Keywords: 12-membered crown ethers ; crystal structure ; conformation peculiarities ; X-ray analysis ; CH...O contacts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structures of two 12-membered crown ethers, benzo-12-crown-4 (1) and naphtho-12-crown-4 (2), have been determined by X-ray analysis. Both structures are molecular. Compound1 is monoclonic,P21/b,a=8.466(3),b=8.019(3),c=33.590(10) Å, γ=90.99(3)o. The unit cell contains two crystallographically independent molecules of1 with similar conformations. Compound2 is also monoclinic,P21/a,a=24.148(8),b=14.535(4),c=7.987(5) Å, γ=102.87(2)o. Two independent molecules in the unit cell have significantly different conformations.
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  • 35
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    Journal of inclusion phenomena and macrocyclic chemistry 15 (1993), S. 159-165 
    ISSN: 1573-1111
    Keywords: Dibenzo-30-crown-10 ; crystal structure ; complexation ; dysprosium isothiocyanate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Crystalline [Dy(NCS)3(dibenzo-30-crown-10)(H2O)2]·H2O·MeCN can be obtained by slowly evaporating a reaction mixture of Dy(NCS)3·nH2O with dibenzo-30-crown-10 in a solution of acetonitrile. The material crystallizes in the monoclinic space groupP21/n, the cell parameters area=11.450(5),b=23.284(4),c=18.424(6)Å, β=106.28(4)°,V=4715Å3,M=968.47,D x=1.36 g cm−1, μ=17.80 cm−1,F(000)=1972,Z=4.2740 independently observed [I≥3σI] reflections were used in the final least-squares refinement leading to an agreement index ofR=0.085. The Dy(III) ion coordination geometry approximates a square antiprism, involving two water oxygens and three dibenzo-30-crown-10 oxygen atoms and three isthiocyanate nitrogens. Hydrogen bonds are formed between the two water molecules and four uncoordinated crown ether oxygen atoms.
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  • 36
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    Journal of inclusion phenomena and macrocyclic chemistry 15 (1993), S. 341-349 
    ISSN: 1573-1111
    Keywords: Molecular asymmetry ; calixarene ; acetone ; clathrate ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal and molecular structure of the 1:1 clathrate of the asymmetric calix[4]arene,1, and acetone has been determined by X-ray analysis. The crystal data are: tetragonal, space groupP4/n,a=b=12.574(6),c=12.572(6) Å,V=1988(2) Å3,Z=2,D x =1.111 g cm−3,D m =1.108 g cm−3. Least-squares refinement based on 1131 observed reflections withF 0〉3σ(F 0) and anisotropic temperature factors led toR=0.096. In spite of the molecular asymmetric calixarene1 the crystal structure has high symmetry, because a part of the host and guest molecules are in disordered states.
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  • 37
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    Journal of inclusion phenomena and macrocyclic chemistry 15 (1993), S. 385-398 
    ISSN: 1573-1111
    Keywords: Hydrogen bonding ; alicyclic diol ; helical tubulate ; crystal structure ; ferrocene ; squalene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The inclusion compounds of 2,8-dimethyltricyclo[5.3.1.13,9]dodecane-syn-2,syn-8-diol,3, with ferrocene and with squalene have been prepared. The crystal structures of these helical tubulate compounds: (3)3·(ferrocene)0.75 [P3121,a=b=13.7480(6),c=7.0312(5) Å,Z=1,R=0.038] and (3)3·(squalene)0.23 [P3121,a=b=13.677(1),c=7.0533(9) Å,Z=1,R=0.042] are described.
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  • 38
    ISSN: 1573-1111
    Keywords: Werner clathrate ; nickel octahedral complex ; tetrahydrofuran ; crystal structure ; NMR ; molecular recognition ; hydrocarbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper addresses the general question: what are the significant guest properties selected by this host when interacting with guest molecules in the liquid phase, resulting in cocrystallization of the host and guest? In particular, to what extent do π electrons in a guest molecule effect its potential as a guest? Werner clathrates of the host [Ni(NCS)2(4-ViPy)4] with mixtures of tetrahydrofuran (THF) and cyclic hydrocarbons as guests have been synthesised and their structures elucidated. Clathrate (1): [Ni(NCS)2(4-ViPy)4](1.78 THF)(0.22 cyclohexane), crystallizes in the orthorhombic space groupP bcn a=9.976(6),b=20.630(25),c=19.861 (4) Å,V=4087Å3,Z=4,R=0.087 for 1461 reflections; (2): [Ni(NCS)2(4-ViPy)4](1.76 THF)(0.24 cyclohexene),P bcn ,a=9.987(7),b=20.614(4),c=19.898(4)Å,V=4096Å3,Z=4,R=0.084 for 1304 reflections; (3): [Ni(NCS)2(4-ViPy)4](0.48 THF)(0.52 1,3-cyclohexadiene), tetragonalI41/a,a=16.898(3),b=16.898(3),c=26.463(6)Å,V=7556Å3,Z=8,R=0.120 for 1698 reflections; (4): [Ni(NCS)2(4-ViPy)4](0.36 THF)(1.04 1,4-cyclohexadiene),I41/a,a=16.986(4),b=16.986(4),c=25.896(15)Å,V=7472Å3,Z=8,R=0.103 for 2025 reflections; (5): [Ni(NCS)2(4-ViPy)4](0.35 THF)(1.05 benzene),I41/a,a=17.102(10),b=17.102(10),c=25.498(8)Å,V=7458Å3,Z=8,R=0.118 for 2200 reflections; (6): [Ni(NCS)2(4-ViPy)4](3 benzene), triclinicP1,a=10.432(24),b=11.155(9),c=21.581(7)Å, α=78.70(5), β=82.60(7), γ=74.09(13)°,V=2361Å3,Z=2,R=0.078 for 3427 reflections. Host-guest ratios and, for mixtures of guests, guest1/guest2 ratios, were elucidated by density and NMR. We show that the conformational freedom of the substituted pyridines is not the primary reason for the clathrating ability of Werner hosts. All six structures show no host-guest interaction at the level of van der Waals interactions. As non-bonding interactions are not observed between the host and guest, this study shows that the above host's selectivity by enclathration of particular guest molecules cannot be accounted for by solid state structural analysis.
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  • 39
    ISSN: 1573-1111
    Keywords: Iminophosphoranes ; amine inclusion compounds ; 13C CPMAS NMR spectroscopy ; salt-like crystalline aggregates ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal and molecular structure is reported for the inclusion compound 2-[o-(triphenylphosphoranylidenamino)benzyliden]amino-1H-2,3-dihydroindazol-3-one/isopropylamine/water3b. The crystal structure consists of discrete dimeric salt-like aggregates joined together by strong N+−H...−O−C hydrogen bonds between pairs of centrosymmetrically-related indazolonate anions and isopropylammonium cations. Six other inclusion compounds have been prepared and characterized by NMR [with propylamine (3a), withtert-butylamine (3c), withsec-butylamine (3d), withtert-pentylamine (3e), with 1-methylbutylamine (3f) and withiso-pentylamine (3g)]. Two different arrangements are found, both with the host being in the anionic form. The guests are either: (i) one protonated amine and one water molecule (3b and3f); or (ii) one protonated amine and the corresponding neutral amine (3a, 3c, 3d, 3e and3g).
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  • 40
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    Journal of inclusion phenomena and macrocyclic chemistry 16 (1993), S. 267-272 
    ISSN: 1573-1111
    Keywords: Crown ether ; ytterbium nitrate ; phen ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title complex was prepared by reacting Yb(NO3)3 (12-crown-4) with 1,10-phenanthroline (hereafter phen) in acetone. It crystallized in the triclinic space group $$P\bar 1$$ witha=10.095(5),b=17.415(4),c=8.710(2) Å α=92.45(2), β=115.83(3), γ=74.08(3)0 andD c=1.85 g cm−3;Z=2. The metal ion in this complex is nine-coordinated to three bidentate nitrate ions, two nitrogen atoms of a phen and a water molecule. The crown ligand is hydrogen bonded to the coordination water molecule. The symmetry change of the crown ether is also discussed.
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  • 41
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1713-1723 
    ISSN: 0887-6266
    Keywords: phthalocyanine siloxane ; crystal structure ; epitaxial growth ; high-resolution electron microscopy ; molecular imaging ; polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Thin films of SiPc(OH)2 (Pc = phthalocyanine) were formed epitaxially on the (001) surface of mica by vacuum deposition and were then polymerized by heat treatment. The molecular packing of the SiPc(OH)2 was determined by electron diffraction and high-resolution electron microscopy as triclinic\documentclass{article}\pagestyle{empty}\begin{document}${\rm P\bar 1} $\end{document} having dimensions a = 0.727, b = 1.307, c = 0.688 nm, α = 102.5, β = 104.2, and γ = 97.4°. This monomer crystal grows with its c-axis parallel to the a-axis of the substrate mica and its bc-plane parallel to the (001) surface of mica. By heat treatment at 320°C, the SiPc(OH)2 polymerized with the c-axis of the polymer parallel to the c-axis of the monomer. At 420°C, the c-axis of the polymer became parallel to the a*-axis of the monomer (i.e., perpendicular to the film surface). From high-resolution electron microscopy of partially polymerized specimens, the polymerization was shown to start at the edges of small monomer crystals. This may be considered to be due to the volume expansion during the polymerization. © 1993 John Wiley & Sons, Inc.
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  • 42
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1923-1940 
    ISSN: 0887-6266
    Keywords: poly(4,4′-oxybibenzoate) ; polymerization ; morphology ; transitions ; crystal structure ; disclination domains ; Iamellae ; single crystals ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 4-Acetoxy 4′-carboxy biphenyl has been polymerized from solution, the bulk melt, and in constrained thin films, all below the melting point of the monomer as measured by differential scanning calorimetry (DSC). An isothermal sublimation-recrystallization-melting (and chemical change)-polymerization-crystallization process is proposed. From solution and in the thin films, single crystals consisting of ca. 100 Å thick lamellae are observed, with evidence for monomer addition-reaction on the end (top and bottom) surfaces. The bulk samples are fibrous, the “fibers” consisting of whisker-like single crystals. The polymer is highly heat and radiation (electron beam) resistant, with numerous successive electron diffraction (ED) patterns from the same crystal or sheared sample permitting comparison of the changes in ED patterns with transitions seen by DSC at ca. 350, 530, and 590°C. Phase I (a = 7.8, b = 5.5, c = 10.8 Å), a possible phase II (a = 15.6, b = 3.6 Å c = unknown), and a phase III (a = 9.0, b = 5.2 = √3a, c = 10.8 Å). Phases I and II are seen in samples polymerized at temperatures at and below 310°C; phase III is observed in samples polymerized at and above 350°C and in sheared samples. © 1993 John Wiley & Sons, Inc.
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  • 43
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1759-1767 
    ISSN: 0887-6266
    Keywords: rigid rod polymer ; thermotropic ; aromatic polyester ; fiber ; modulus ; crystal structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fiber spinning and mechanical properties of four rigid polyesters with alkoxy substituents of different length and placement were evaluated. Properties of oriented fibers from the polymer with dodecyloxy substituents on the terephthalate moiety, PTA12HQ, were significantly affected by the crystal modification. At room temperature the following properties (tensile modulus E, tensile strength σb, and strain at break εb) could be obtained: E = 9.5 GPa, σb = 85 MPa and εb = 1.1% for phase Lf (the “frozen in layered mesophase”); E = 10.4 GPa, σb = 59 MPa and εb = 0.6% for modification A; E = 17.3 GPa, σb = 158 MPa and εb = 1.2% for modification B. Because of the higher amount of main chains per cross sectional area the polymer with hexyloxy side chains, PTA6HQ, showed better properties at a comparable degree of molecular orientation: E = 24 GPa, σb = 270 MPa, εb = 1.4%. Fibers obtained from the polyester with dodecyloxy substituents on the hydroquinone moiety, PTAHQ12, were too brittle to handle. The polyester with dodecyloxy substituents on both moieties, PTA12HQ12, was spun from the isotropic melt. Because of the obtained low degree of orientation, properties (E = 1 GPa, σb = 40 MPa, and εb = 6.3%) were governed by interactions between the chains (the main chains are not load-bearing). © 1993 John Wiley & Sons, Inc.
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  • 44
    ISSN: 0192-253X
    Keywords: Heat shock protein ; maize ; mi-crosporogenesis ; gametogenesis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The small (18-kDa) heat shock proteins (hsps) of maize are encoded by a complex multigene family. In a previous report, we described the genetic information from cDNAs encoding two different members of the family. In this communication, we report the isolation and characterization of cDNA and genomic clones encoding information for a third member of this hsp family (c/gMHSP18-1). DNA fragments containing nucleotide sequences common to, or specific for, each of these characterized 18-kDa genes were prepared and used as probes to assess the expression of these genes during microsporogenesis and development of the gametophyte in an inbred line of maize (Oh43). Our results demonstrate (1) that mRNA transcripts encoding the 18-kDa hsps are expressed and/or accumulate during microsporogenesis, and (2) that genes encoding two of the characterized 18-kDa hsps are expressed and/or accumulate independently, in a stage-specific manner during microsporogenesis. These observations imply that the stage-specific expression of particular 18-kDa hsp genes results from gene-specific regulation during microsporogenesis and gametophyte development rather than from an overall activation of the heat shock or stress response. © 1993Wiley-Liss, Inc.
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  • 45
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 42-50 
    ISSN: 0192-253X
    Keywords: Development ; transcnption ; heat shock protein ; microinjection ; polymerase chain reaction ; Xenopus laevis ; mRNA ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the present study, we have examined the regulation of expression of a newly isolated member of the hsp 30 gene family, hsp 30C. Using RT-PCR, we found that this gene was first heat-inducible at the tailbud stage of development. We also examined the expression of two microinjected modified hsp 30C gene constructs in Xenopus embryos. One of the constructs had 404 bp of hsp 30C 5′-flanking region, whereas the other had 3.6 kb. Both gene constructs had 1 kb of 3′-flanking region. RT-PCR assays were employed to detect the expression of these microinjected genes. The presence of extensive 5′- and 3′-flanking regions of the hsp 30C gene did not confer proper developmental regulation, since heat-inducible expression of both of the microinjected constructs was detectable at the midblastula stage. The premature expression of the microinjected hsp 30 gene was not a result of high plasmid copy number or the presence of plasmid DNA sequences. These results suggest that the microinjected genes contain all the cis-acting DNA sequences required for correct heat-inducible regulation but do not contain the elements required for the proper regulation of hsp 30 gene expression during development. It is possible that regulatory elements controlling the developmental expression of the hsp30 genes may reside upstream or downstream of the entire cluster. © 1993Wiley-Liss, Inc.
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  • 46
    ISSN: 0192-253X
    Keywords: hsp70 ; heat shock ; fungus ; steroid hormone ; secretion ; mycelial branching ; sexual differentiation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the filamentous oomycete fungus Achlya, the differentiation of gamete bearing structures on vegetative hyphae of the male mating type, is induced by the Achlya steroid hormone, antheridiol. Among the several metabolically labeled intracellular proteins whose synthesis or accumulation is altered by hormone treatment are steroid-induced 85-kDa and 68- to 78-kDa proteins. The 85-kDa protein was previously shown to be the Achlya heat shock protein hsp85 [Brunt et al., 1990; Brunt and Silver, 1991], a component of the putative Achlya steroid hormone receptor. It was of interest to determine if the antheridiol-induced “70-kDa” proteins were hsp70-family heat shock proteins and if hormone treatment-induced changes in the level of hsp70 transcripts. Two different Achlya hsp70 genomic sequences were cloned and used to investigate these questions. The two hsp70 sequences recognized two different mycelial transcript populations, one of which was regulated also by decreased glucose. Of note, both of the two hsp70 transcript populations were found to be regulated by antheridiol. The hormone-induced chcnges in hsp70 transcript levels were temporally correlated with the onset of massive lateral hyphal branching and alterations in the pattern of secreted N-linked glycoproteins which occur in hormone-treated mycelia. To our kncwledge, this represents one of the first reports on changes in hsp70 proteins and transcripts during fungal differentiation. Our results may have implications for the role of heat shock proteins in hyphal branching and secretion in filamentous fungi and perhaps other cell types. © 1993Wiley-Liss, Inc. Inc.
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  • 47
    ISSN: 0192-253X
    Keywords: Heat shock inducible promoters ; hsp90 ; Zea mays ; developmental expression ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have isolated two genes from Zea mays encoding proteins of 82 and 81 kD that are highly homologous to the Drosophila 83-kD heat shock protein gene and have analyzed the structure and pattern of expression of these two genes during heat shock and development. Southern blot analysis and hybrid select translations indicate that the highly homologous hsp82 and hsp81 genes are members of a small multigene family composed of at least two and perhaps three or more gene family members. The deduced amino acid sequence of these proteins based on the nucleotide sequence of the coding regions shows 64-88% amino acid homology to other hsp90 family genes from human, yeast, Drosophila, and Arabidopsis. The promoter regions of both the hsp82 and hsp81 genes contain several heat shock elements (HSEs), which are putative binding sites for heat shock transcription factor (HSF) commonly found in the promoters of other heat shock genes. Gene-specific oligonucleotide probes were synthesized and used to examine the mRNA expression patterns of the hsp81 and hsp82 genes during heat shock, embryogenesis, and pollen development. The hsp81 gene is only mildly heat inducible in leaf tissue, but is strongly expressed in the absence of heat shock during the premeiotic and meiotic prophase stages of pollen development and in embryos, as well as in heat-shocked embryos and tassels. The hsp82 gene shows strong heat inducibility at heat-shock temperatures (37-42°C) and in heat shocked embryos and tassels but is only weakly expressed in the absence of heat shock. Promoter-GUS reporter gene fusions made and analyzed by transient expression assays in Black Mexican Sweet (BMS) Maize protoplasts also indicate that the hsp82 and hsp81 are regulated differentially. The hsp82 promoter confers strong heat-inducible expression of the GUS reporter gene in heat-treated cells (60- to 80-fold over control levels), whereas the hsp81 promoter is only weakly heat inducible (5- to 10-fold over control levels). © 1993Wiley-Liss, Inc.
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  • 48
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 58-68 
    ISSN: 0192-253X
    Keywords: Ferritin ; heat shock ; development ; sea urchin ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A 20-kD protein identified as a subunit of the iron-binding protein ferritin is present in S. purpuratus and L. pictus sea urchin embryos. The synthesis of the protein is stimulated by an elevation in temperature or by an increase in iron supply. The developmental expression of this protein and its regulation during normal development and upon heat shock was investigated. In L. pictus, ferritin is present in the unfertilized egg and, as determined by Western blot analysis, its concentration remains approximately constant after fertilization up to the gastrulc-pluteus stage; there is a small transient decrease in the level of the protein in the early blastula at a time coinciding with the first clear indication of its de novo synthesis. Northern blots reveal no cytoplasmic ferritin transcripts in the unfertilized egg, but there occurs a dramatic increase in the RNA level from the late morulaearly blastula stage (12-14 hr) to the mesenchyme blastula-early gastrula (25-30 hr) stage. This developmentally regulated increase in the constitutive concentration of ferritin RNA is correlatable with the normal onset of synthesis of the protein. The overall degree and nature of induction of ferritin by heat is dependent on the developmental stage: at 10-16 hr postfertilization heat shock elicits an increase in both the concentration of RNA and the synthesis of the protein; in hatched blastula (18 hr) and in later embryos heat shock increases ferritin synthesis, without a corresponding increase in the mRNA level. It appears that different mechanisms operate in the developing sea urchin embryo to regulate the expression of ferritin during normal development and on exposure to heat stress, one dependent on the concentration of ferritin transcripts and another operating at the level of translational control. © 1993Wiley-Liss, Inc.
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  • 49
    Electronic Resource
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    Developmental Genetics 14 (1993), S. 87-91 
    ISSN: 0192-253X
    Keywords: Heat shock ; translation ; transcription ; development ; mRNA ; differentiation ; mammals ; birds ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 50
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 103-111 
    ISSN: 0192-253X
    Keywords: Mouse ; development ; small heat shock protein ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have investigated the developmental and tissue-specific distribution of the mouse small hsp25 by immunohistology using an antibody that specifically identifies hsp25. Our analysis shows that the relative amount of hsp25 increases during embryogenesis. Through days 13-20 of embryogenesis, hsp25 accumulation is predominant in the various muscle tissues, including the heart, the bladder, and the back muscles. hsp25 is detectable also in neurons of the spinal cord and the purkinje cells. Furthermore analysis of the closely related α, B-crystallin shows that in several tissues, including the bladder, the notochordal sheath and the eye lens both proteins are coexpressed. Our studies demonstrate that mammalian hsp25 accumulation is developmentally regulated during mouse embryogenesis and support the view of an important functional role of small heat shock proteins in normal cell metabolism. © 1993Wiley-Liss, Inc.
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  • 51
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    Developmental Genetics 14 (1993), S. 119-126 
    ISSN: 0192-253X
    Keywords: Spermatogenesis ; HSP90 proteins ; HSP70 proteins ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This study extends to the protein level our previous observations, which had established the stage and cellular specificity of expression of hsp86 and hsp84 in the murine testis in the absence of exogenous stress. Immunoblot analysis was used to demonstrate that HSP86 protein was present throughout testicular development and that its levels increased with the appearance of differentiating germ cells. HSP86 was most abundant in the germ cell population and was present at significantly lower levels in the somatic cells. By contrast, the HSP84 protein was detected in the somatic cells of the testis rather than in germ cells. The steady-state levels of HSP86 and HSP84 paralleled the pattern of the expression of their respective mRNAs, suggesting that regulation at the level of translation was not a major mechanism controlling hsp90 gene expression in testicular cells. Immunoprecipitation analysis revealed that a 70-kDa protein coprecipitated with the HSP86/HSP84 proteins in testicular homogenates. This protein was identified as an HSP70 family member by immunoblot analysis, suggesting that HSP70 and HSP90 family members interact in testicular cells. © 1993Wiley-Liss, Inc.
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  • 52
    ISSN: 0192-253X
    Keywords: Heat-shock proteins ; teratogenicity, tolerance and cross-tolerance ; neural tube defects ; gene expression ; In situ transcription ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The present study was undertaken to examine the role of heat shock response in the development of tolerance and cross-tolerance in an in vivo murine model of teratogen-induced neural tube defects. The experimental paradigm designed to address this question was to utilize inbred mouse strains that differed in their sensitivity to hyperthermia and valproic acid induced neural tube defects, subjecting the dams to subteratogenic pretreatments with either heat or valproic acid at two different timepoints during development prior to the administration of the teratogenic insult. A statistically significant reduction in the frequency of neural tube defects and/or embryolethality following a pretreatment in dams subsequently exposed to a teratogenic treatment was considered evidence for the induction of tolerance. This was observed in the SWV embryos exposed to the 38°C pretreatment at 8:06 and to embryos exposed to either pretreatment temperature at 8:10 priorto a teratogenic heat shock at 8:12. In the LM/Bc embryos, only the 41°C pretreatment at 8:06 induced thermotolerance. There was no evidence of tolerance induced in either mouse strain using valproic acid. On the other hand, cross-tolerance was clearly demonstrated in this study, with a low temperature (41°C) pretreatment successfully protecting SWV fetuses from a subsequent teratogenic treatment with valproic acid, while valproic acid (200 mg/kg) was effective in reducing the risk of hyperthermia-induced neural tube defects in the LM/Bc fetuses. In all instances, tolerance was induced in the absence of significant induction of hsp synthesis. The lack ofconcordance between hsps and thermotolerance suggests that some other factor(s) is involved in conferring thermotolerance on developing murine embryos. © 1993 Wiley-Liss, Inc.
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  • 53
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    Developmental Genetics 14 (1993), S. 249-249 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 54
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 204-211 
    ISSN: 0192-253X
    Keywords: Inductive cell interactions ; diffusible molecules ; animal explants ; growth factors ; cyclo-heximide ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mesoderm development in Xenopus laevis depends on inductive cell interactions mediated by diffusible molecules. The mesoderm inducer activin is capable of redirecting the development of animal explants both morphologically and biochemically. We have studied the induction of four regulatory genes, Mix. 1, goosecoid (gsc), Xlim-1 and Xbra in such explants by activin, and the influence of other factors on this induction. Activin induction of gsc is strongly enhanced by dorsalization of the embryo by LiCl, while expression of the other genes is only slightly enhanced. The protein synthesis inhibitor cycloheximide (CHX) inhibits the activin-dependent induction of Xbra partially, while induction of Mix. 1 and Xlim- 1 is essentially unaffected. In contrast, gsc shows strong superinduction in the presence of activin and CHX, and can be induced in animal explants by CHX alone. Induction and superinduction by CHX have previously been observed for immediate early genes in a variety of systems, notably for the activation of c-fos expression by serum stimulation, but have not been reported in early amphibian embryos. © 1993Wiley-Liss, Inc.
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  • 55
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    Developmental Genetics 14 (1993), S. 225-238 
    ISSN: 0192-253X
    Keywords: Growth factor ; wound healing ; embryo ; in situ hybridisation ; immunohistochemistry ; gene expression ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The TGFβ family of growth factors has been implicated as playing a significant role in many aspects of embryonic morphogenesis, and also as a mediator of adult tissue repair processes. Unlike the situation in the adult, rissue repair in the embryo does not result in scarring, and it has been suggested that this might be due, in part, to reduced levels of growth factors, particularly TGFβ, at the wound site. We have examined the expression patterns of TGFβ genes following wounding of limb bud lesions in cultured Ell.5 mouse embryos. The timetable of wound closure was investigated by standard light and electron microscopy from the time of wounding until the lesion had re-epithelialised 24 hours later. The expression of transcripts for each of the three TGFβ genes was examined at various time points during the healing process using radioactive in situ hybridisation to tissue sections and wholemount non-radioactive in situ hybridisation to embryo pieces. Within l to 3 hours of wounding, transcripts encoding TGFβl were rapidly induced within the epithelial cells of the wound margin, particularly those cells at the ventral aspect of the wound. By 3 to 6 hours post-wounding, TGFβl transcripts were detectable in the mesenchyme of the wound bed. No TGFβS induction was observed, and possible TGFβ2 induction was largely obscured by endogenous expression associated with pre-cartilage mesenchymal condensation. Immunocytochemical analysis of tissue sections of the wound demonstrated a rapid induction of TGFβl protein within l hour post-wounding, but also a subsequent rapid clearance of the protein from the wound site such that, by 18 hours post-wounding, TGFβl levels had returned to near background. These data are discussed in terms of the molecular mechanisms underlying embryonic wound healing and the significance of the results to an understanding of scarring following adult tissue repair. © 1993Wiley-Liss, Inc.
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  • 56
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    Developmental Genetics 14 (1993), S. 313-322 
    ISSN: 0192-253X
    Keywords: Dictyostelium ; glycogen phosphorylase ; gene regulation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A crucial developmental event in the cellular slime mold, Dictyostelium discoideum, is glycogen degradation. The enzyme that catalyzes this degradation, glycogen phosphorylase 2 (gp-2), is developmentally regulated and cAMP appears to be involved in this regulation. We have examined several aspects of the cAMP regulation of gp-2. We show that addition of exogenous cAMP to aggregation competent amoebae induced the appearance of gp-2 mRNA. The induction of gp-2 mRNA occurred within 1 and 1.5 h after the initial exposure to cAMP. Exposure to exogenous cAMP concentrations as low as 1.0 μM could induce gp-2 mRNA. We also examined the molecular mechanism through which cAMP induction of gp-2 occurs. Induction of gp-2 appears to result from a mechanism that does not require intracellular cAMP signaling, and may occur directly through a cAMP binding protein without the requirement of any intracellular signalling. We also examined the promoter region of the gp-2 gene for cis-acting elements that are involved in the cAMP regulation of gp-2. A series of deletions of the promoter were fused to a luciferase reporter gene and then analyzed for cAMP responsiveness. The results indicated that a region from -258 nucleotides to the transcriptional start site is sufficient for essentially full activity and appears to carry all necessary cis-acting sites for cAMP induction. Further deletion of 58 nucleotides from the 5′ end, results in fivefold less activity in the presence of cAMP. Deletion of the next 104 nucleotides eliminates the cAMP response entirely. © 1993Wiley-Liss, Inc.
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  • 57
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    Developmental Genetics 14 (1993), S. 274-281 
    ISSN: 0192-253X
    Keywords: Transgenesis ; antisense RNA ; wingless ; spermatogenesis ; phosphoglycerate kinase 2 promoter ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have used mice transgenic for an antisense construct for Wnt-1 to study the role of this gene in post-meiotic sperm development. The human PGK-2 promoter provided levels of Wnt-1 antisense mRNA in testes in 5 transgenic lines greatly in excess of Wnt-1 mRNA concentrations, and Wnt-1 mRNA levels were greatly decreased in the lines, by 98% in three of them. There was a general correlation between copy number of the insert, levels of antisense RNA, and decreases in mRNA. There was little effect of the antisense transgene on fertility or testicular histology suggesting that normal levels of Wnt- 1 transcript are not essential for spermatogenesis. © 1993Wiley-Liss, Inc.
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  • 58
    ISSN: 0192-253X
    Keywords: Ethylene ; plant senescence ; fruit ripening ; polygalacturonase ; ACC synthase ; antisense RNA ; translational control ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Fruit ripening is one of the most dramatic developmental transitions associated with extensive alteration in gene expression. The plant hormone ethylene is considered to be the causative ripening agent. Transgenic tomato plants were constructed expressing antisense or sense RNA to the key enzyme in the ethylene (C2H4) biosynthetic pathway, 1 -aminocyclopropane-1-carboxylate (ACC) synthase using the constitutive CaMV 35S and fruit specific E8 promoters. Fruits expressing antisense LE-ACS2 RNA produce less ethylene and fail to ripen only when ethylene production is suppressed by more than 99% (〉0.1 nl/g fresh weight). Ethylene production is considerably inhibited (50%) in fruits expressing sense LE-ACS2 RNA. Antisense fruits accumulate normal levels of polygalacturonase (PG), ACC oxidase (pTOM13), E8, E17, J49, and phytoene desaturase (D2) mRNAs which were previously thought to be ethylene-inducible. E4 gene expression is inhibited in antisense fruits and its expression is not restored by treatment with exogenous propylene (C3H6). Antisense fruits accumulate PG mRNA, but it is not translated. Immunoblotting experiments indicate that the PG protein is not expressed in antisense fruits but its accumulation is restored by propylene (C3H6) treatment. The results suggest that at least two signal-transduction pathways are operating during tomato fruit ripening. The independent (developmental) pathway is responsible for the transcriptioncl activation of genes such as PG, ACC oxidase, E8, E17, D2, and J49. The ethylene-dependent pathway is responsible for the transcriptional and posttranscriptional regulation of genes involved in lycopene, aroma biosynthesis, and the translatability of developmentally regulated genes such as PG. © 1993Wiley-Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America. © 1993Wiley-Liss, Inc.
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  • 59
    ISSN: 0192-253X
    Keywords: Antisense ; phosphorothioate oligonucleotides ; jun-B ; c-jun neuronal development ; cell differentiation ; proliferation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Induction of the jun-B and/or c-jun transcription factors is part of the immediate early response to diverse stimuli that induce alterations in cellular programs. While c-jun is a protooncogene whose expression is required for induction of cell proliferation, jun-B has recently been found to be induced by stimuli inducing differentiation in various cell lines. Furthermore, its expression is largely restricted to differentiating cells during embryogenesis. To determine the functional significance of these findings, we used antisense phosphorothioate oligodeoxynucleotides to inhibit expression of the two genes in proliferating and neuronally differentiating cells. While selective inhibition of c-jun expression reduced proliferation rates, inhibition of jun-B protein synthesis markedly increased proliferation in 3T3 fibroblasts, human mammary carcinoma cells and PC-12 pheochromocytoma cells, suggesting jun-B involvement in negative growth control. Neuronal differentiation of PC-12 cells induced by nerve growth factor (NGF) was prevented by inhibition of jun-B protein synthesis. PC-12 cells not only failed to grow neurites but also remained in the proliferative state. Furthermore, in cultured primary neurons from rat hippocampus, inhibition of jun-B expression, again, markedly reduced morphological differentiation. Conversely, inhibition of c-jun protein synthesis enhanced morphological differentiation of both primary neurons and PC-12 tumor cells. Thus, jun-B expression is required for neuronal differentiation and its balance with c-jun activity is involved in regulating key steps in proliferation and differentiation processes. © 1993Wiley-Liss, Inc.
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  • 60
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 61
    ISSN: 0192-253X
    Keywords: Translation ; elongation factors ; development ; Xenopus laevis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the amphibian Xenopus laevis, the elongation factor 1α proteins (EF-1α) synthesised in oocytes and somatic cells correspond to distinct gene products. Furthermore, the somatic EF-1α gene (EF-1αS) produces one of the most highly expressed early zygotic transcripts in the embryo. The functional recycling of EF-1α (conversion of EF-1α-GDP to EF-1α-GTP) is assured by the EF-1βγ complex. We show here that in Xenopus laevis embryos, contrary to the situation for EF-1α, EF-1β, and EF-1γ mRNAs are transcribed from the same genes in oocytes and somatic cells. In addition, the onset of transcription of the EF-1β and EF-1γ genes from the zygotic gencme occurs several hours after that of the somatic EF-1αS gene. Therefore, during early Xenopus development the expression of these three elongation factors is not co-ordinated at the transcriptional level. The consequences of this uncoupling on the efficiency of translational elongation in the early Xenopus embryo are discussed. © 1993 Wiley-Liss, Inc.
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  • 62
    ISSN: 0192-253X
    Keywords: Meiotic maturation ; translation ; protein synthesis initiation factors ; mRNA cap binding protein ; eIF-4E ; eIF-2B ; GEF ; eIF-4F ; phosphorylation ; protein kinase C ; cdc2 kinase ; p34cdc2 kinase ; MAP kinase ; MBP kinase ; casein kinase II ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The stimulation of translation in starfish oocytes by the maturation hormone, 1-methyladenine (1-MA), requires the activation or mobilization of both initiation factors and mRNAs [Xu and Hille, Cell Regul. 1:1057, 1990]. We identify here the translational initiation complex, eIF-4F, and the guanine nucleotide exchange factor for eIF-2, eIF-2B, as the rate controlling components of protein synthesis in immature oocytes of the starfish, Pisaster orchraceus. Increased phosphorylation of eIF-4E, the cap binding subunit of the eIF-4F complex, is coincident with the initial increase in translational activity during maturation of these oocytes. Significantly, protein kinase C activity increased during oocyte maturation in parallel with the increase in eIF-4E phosphorylation and protein synthesis. An increase in the activities of cdc2 kinase and mitogen-activated myelin basic protein kinase (MBP kinase) similarly coincide with the increase in eIF-4E phosphorylation. However, neither cdc2 kinase nor MBP kinase phosphorylates eIF-4E in vitro. Casein kinase II activity does not change during oocyte maturation, and therefore, cannot be responsible for the activation of translation. Treatment of oocytes with phorbol 12-myristate 13-acetate, an activator of protein kinase C, for 30 min prior to the addition of 1-MA resulted in the inhibition of 1-MA-induced phosphorylation of eIF-4E, translational activation, and germinal vesicle breakdown. Therefore, protein kinase C may phosphorylate eIF-4E, after very early events of maturation. Another possibility is that eIF-4E is phosphorylated by an unknown kinase that is activated by the cascade of reactions stimulated by 1-MA. In conclusion, our results suggest a role for the phosphorylation of eIF-4E in the activation of translation during maturation, similar to translational regulation during the stimulation of growth in mammalian cells. © 1993 Wiley-Liss, Inc.
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  • 63
    ISSN: 0192-253X
    Keywords: Antisense inhibition ; Wnt-1 ; Wnt-3a ; Neural crest ; Central nervous system ; Hindbrain ; Midbrain ; Spinal cord ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Wnt-1 and Wnt-3a proto-on-cogenes have been implicated in the development of midbrain and hindbrain structures. Evidence for such a role has been derived from in situ hybridization studies showing Wnt-1 and -3a expression in developing cranial and spinal cord regions and from studies of mutant mice whose Wnt-1 genes have undergone targeted disruption by homologous recombination. Wnt-1 null mutants exhibit cranial defects but no spinal cord abnormalities, despite expression of the gene in these regions. The absence of spinal cord abnormalities is thought to be due to a functional compensation of the Wnt-1 deficiency by related genes, a problem that has complicated the analysis of null mutants of other developmental genes as well. Herein, we describe the attenuation of Wnt-1 expression using antisense oligonucleotide inhibition in mouse embryos grown in culture. We induce similar mid- and hindbrain abnormalities as those seen in the Wnt-1 null mutant mice. Attentuation of Wnt-1 expression was also associated with cardiomegaly resulting in hemostasis. These findings are consistent with the possibility that a subset of Wnt-1 expressing cells include neural crest cells known to contribute to septation of the truncus arteriosus and to formation of the visceral arches. Antisense knockout of Wnt-3a, a gene structurely related to Wnt-1, targeted the forebrain and midbrain region, which were hy-poplastic and failed to expand, and the spinal cord, which exhibited lateral outpocketings at the level of the forelimb buds. Dual antisense knockouts of Wnt-1 and Wnt-3a targeted all brain regions leading to incomplete closure of the cranial neural folds, and an increase in the number and severity of outpocketings along the spinal cord, suggesting that these genes complement one another to produce normal patterning of the spinal cord. The short time required to assess the mutant phenotype (2 days) and the need for limited sequence information of the target gene (20-25 nu-cleotides) make this antisense oligonucleotide/ whole embryo culture system ideal for testing the importance of specific genes and their interactions in murine embryonic development. © 1993 Wiley-Liss, Inc.
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  • 64
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 397-406 
    ISSN: 0192-253X
    Keywords: Cleavage stage ; maternal mRNA ; polysomes ; translational regulation ; sea urchins ; cell cycle ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Previous studies of newly synthesized proteins during early development in sea urchins have revealed several different patterns of synthesis that can be used to predict the existence of mRNA classes with distinct regulatory controls. We have identified clones for abundant maternal mRNAs that are actively translated during early development by screening a cDNA library prepared from polysomal poly(A) + RNA isolated from 2-cell stage (2-hour) Strongylocentrotus purpuratus embryos. Probes prepared from these cDNA clones and several previously characterized maternal mRNA cDNAs were used to compare relative levels of individual mRNAs in eggs and embryos and their translational status at various developmental stages. These abundant mRNAs can be classified into two major groups which we have termed cleavage stage-specific (CSS) and post cleavage stage (PCS) mRNAs. The relative levels of the CSS mRNAs are highest during the rapid cleavage stage and decrease dramatically at the blastula stage (12-hours). In contrast, PCS mRNAs are present at relatively low levels during the rapid cleavage stage and then increase at the blastula stage. Polysome partition profiles reveal that CSS mRNAs are translated more efficiently than PCS mRNAs in the unfertilized egg, at fertilization, and during the cleavage stages. Following the blastula stage, some CSS transcripts move out of polysomes and accumulate as untranslated RNAs, while newly transcribed PCS mRNAS are recruited into polysomes. These data suggest that the rapid cell cycles following fertilization require high levels of specific cleavage stage proteins, and the synthesis of these proteins occurs preferentially over PCS mRNAs. © 1993Wiley-Liss, Inc.
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  • 65
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 412-423 
    ISSN: 0192-253X
    Keywords: Sea urchin ; fertilization ; eIF-4α ; protein synthesis regulation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The developmentally regulated inhibitor of eIF-4 function found in unfertilized sea urchin eggs has been partially purified and its mechanism of action studied in vitro using purified recombinant eIF-4α and cell-free translation systems. The results demonstrate that although the phosphorylation of eIF-4α is necessary to promote protein synthesis, it is not sufficient to maintain all aspects of eIF-4 function. The egg inhibitor does not change eIF-4α phosphorylation state. During the blockage of initiation caused by the egg inhibitor, eIF-4α remains phosphorylated but accumulates in a 48S initiation intermediate. This suggests that the egg inhibitor functions by preventing the release of eIF-4α from the small ribosomal subunit. The characteristics of the inhibitor in a reticulocyte translation system demonstrate that eIF-4 activity is inhibited within 3-6 min. However, the inhibitor's characteristics in a mRNA-dependent translation system contrast with this. Preincubation with the inhibitor for 5-25 min prior to the addition of mRNA does not prevent endogenous eIF-4 from participating in translation but diminishes its ability to be reutilized, consistent with the accumulation of eIF-4α on the small ribosomal subunit. The ribosomal localization of the inhibitor suggests that it could prevent eIF-4α release by direct binding. The gradual inactivation of the inhibitor following fertilization indicates that it represents a component of a novel regulatory cascade that modulates eIF-4 activity. © 1993 Wiley-Liss, Inc.
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  • 66
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 449-459 
    ISSN: 0192-253X
    Keywords: Drosophila ; Mst87F ; translational and transcriptional control ; TCE ; binding protein(s) ; UV crosslink ; EMSA ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have previously identified a 12 nucleotide long sequence element, the TCE, that was demonstrated to be necessary for translational control of expression in the male germ line of Drosophila melanogaster (Schäfer et al., 1990). It is conserved among all seven members of the Mst(3)CGP gene family, that encode structural proteins of the sperm tail. The TCE is invariably located in the 5′ untranslated region (UTR) at position + 28 relative to the transcription start site. In this paper we analyse the mode of action of this element. We show that protein binding occurs at the TCE after incubation with lestis protein extracts from Drosophila melanogaster. While several proteins are associated with the translational control element in the RNA, only one of these proteins directly crosslinks to the sequence element. The binding activity is exclusively observed with testis protein extracts but can be demonstrated with testis extracts from other Drosophila species as well, indicating that regulatory proteins involved in translational regulation in the male germ line are conserved. Although binding to the TCE can occur independent of its position relative to the transcription start site of the in vitro transcripts, its function in vivo is not exerted when shifted further downstream within the 5′ UTR of a fusion gene. In addition to being a translational control element the TCE also functions as a transcriptional regulator. Consequently, a DNA-protein complex is also formed at the TCE. In contrast to the RNA-protein complexes we find DNA-protein complexes with protein extracts of several tissues of Drosophila melanogaster. © 1993 Wiley-Liss, Inc.
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  • 67
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 471-484 
    ISSN: 0192-253X
    Keywords: Sex determination ; translational control ; germ line ; C. elegans ; mog genes ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The Caenorhobditis elegans XX animal possesses a hermaphrodite germ line, producing first sperm, then oocytes. In this paper, we report the genetic identification of five genes, mog-2, mog-3, mog-4, mog-5, and mog-6, that influence the hermaphrodite switch from sper-matogenesis to oogenesis. In mcg-2-mog-6 mutants, spermatogenesis continues past the time at which hermaphrodites normally switch into oogenesis and no oocytes are observed. Therefore, in these mutants, germ cells are transformed from a female fate (oocyte) to a male fate (sperm). The fem-3 gene is one of five genes that acts at the end of the germline sex determination pathway to direct spermatogenesis. Analyses of mog;fem-3 double mutants suggest that the mog-2-mog-6 genes act before fem-3; thus these genes may be in a position to negatively regulate fem-3 or one of the other terminal regulators of germline sex determination. Double mutants of fem-3 and any one of the mog mutations make oocytes. Using these double mutants, we show that oocytes from any mog;fem-3 double mutant are defective in their ability to support embryogenesis. This maternal effect lethality indicates that each of the mog genes is required for embryogenesis. The two defects in mog-2-mog-6 mutants are similar to those of mog-1: all six mog genes eliminate the sperm/oocyte switch in hermaphrodites and cause maternal effect lethality. We propose that the mog-2-mog-6 mutations identify genes that act with mog-1 to effect the sperm/oocyte switch. We further speculate that the mog-1-mog-6 mutations all interfere with translational controls of fem-3 and other maternal mRNAs. © 1993 Wiley-Liss, Inc.
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  • 68
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 492-499 
    ISSN: 0192-253X
    Keywords: Meiotic maturation ; Spisula ; translational control ; 3′ untranslated region ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: During meiotic maturation of Spisula oocytes, maternal mRNAs undergo changes in translation and in the length of their poly(A) tails. In general, those mRNAs that are translationally activated, i.e., unmasked become polyadenylated, while deactivated mRNAs lose their poly(A) tails. The activated class of mRNAs encode ribonucleotide reductase, cyclins A and B and histone H3, while the proteins that stop being made include tubulin and actin. Previously, we demonstrated that mRNA-specific unmasking can be brought about in vitro by preventing the interaction of protein(s) with central portions of the 3′ noncoding regions (masking regions) of ribonucle-otide reductase and cyclin A mRNAs. In this report, we show that clam egg extracts are capable of sequence-specific polyadenylation of added RNAs since the 3′ untranslated regions (UTRs) of ribonu-cleotide reductase and histone H3 mRNAs are polyadenylated, while that of actin mRNA is not. In contrast, oocyte extracts, as in vivo, are essentially devoid of polyadenylation activity. We present an initial characterisation of the cis-acting sequences in the 3′ UTR of ribonucleotide reductase mRNA required for polyadenylation. The results suggest that the sequences for cytoplasmic polyadenylation are more complex and extensive than those determined in vertebrates and that they may partly overlap with the masking regions. © 1993 Wiley-Liss, Inc.
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  • 69
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 485-491 
    ISSN: 0192-253X
    Keywords: Translational contral ; maternal mRNA ; polyadenylation ; Urechis caupo ; fertilization ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Fertilization of Urechis coupo oocytes stimulates dramatic changes in the pattern of protein synthesis. This shift is brought about entirely through selective translation of the large pool of maternal mRNAs synthesized and stored during oogenesis. My laboratory has identified cDNA clones to more than 20 different Urechis maternal mRNAs. These have been used to determine whether the complementary mRNAs are translated in oocytes or embryos, and to analyze the polyad-enylation status of the mRNAs at different stages. For 14 of the mRNAs, multiple, overlapping cDNA clones were isolated, and the complete sequence of the mRNA molecule was determined. Of these 14 mRNAs, half are from the subset that is translated in growing and full-grown oocytes, but not in embryos. These 7 mRNAs have poly(A) tails before fertilization. The other 7 are from the subset that is not translated at any time before fertilization, and has very short poly(A) tails in oocytes. After fertilization these mRNAs are recruited onto polysomes and extensively polyadenylated. The sequence data from the two classes of maternal mRNAs was compared in an attempt to identify consensus sequences that could regulate translation directly, or indirectly, by controlling polyadenylation or secondary structure formation. Two features of the sequences correlate very well with the translation and polyadenylation of the different mRNAs-the identity of the base immediately preceding the AUG start codon, and the presence of the sequences UUUUA and UUUUUA in the 3′ untranslated region. © 1993 Wiley-Liss, Inc.
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  • 70
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 381-386 
    ISSN: 0044-2313
    Keywords: Sodium tetraamido aluminate ; sodium tetraamido gallate ; crystal structure ; IR spectra ; thermal behaviour ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Redetermination of Structure and Properties of the Isotypic Sodium Tetraamido Metallates of Aluminium and GalliumCrystals for x-ray structure determination of NaAl(NH2)4 and NaGa(NH2)4 were obtained by the reaction of the metals with ammonia in autoclaves at 100°C and P(NH3) = 60 bar within 7 days. The compounds crystallize isotypic in the space group P21/c with Z = 4 NaAl(NH2)4 a = 7.328(2) Å, b = 6.047(2) Å, c = 13.151(3) Å, β = 94.04(1)° NaGa(NH2)4 a = 7.4087(8) Å, b = 6.0917(5) Å, c = 12.855(2) Å, β = 92.10(1)°The structures were refined inclusively all H-positions of the amide ions. The ternay amides are furthermore characterized by their IR spectra and their thermal behaviour.
    Notes: Für röntgenographische Strukturbestimmungen geeignete Kristalle von NaAl(NH2)4 und NaGa(NH2)4 wurden durch Umsetzung der Metalle mit NH3 in Autoklaven bei 100°C und P(NH3) = 60 bar in 7d erhalten. Die Verbindungen kristallisieren isotyp in der Raumgruppe P21/c mit Z = 4 NaAl(NH2)4 a = 7,328(2) Å, b = 6,047(2) Å, c = 13,151(3) Å, β = 94,04(1)° NaGa(NH2)4 a = 7,4087(8) Å, b = 6,0917(5) Å, c = 12,855(2) Å, β = 92,10(1)°Die Strukturen wurden einschließlich aller H-Lagen der NH2--Ionen bestimmt. Die ternären Amide werden außerdem IR-spektroskopisch und bezüglich ihres thermischen Verhaltens charakterisiert.
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  • 71
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 421-423 
    ISSN: 0044-2313
    Keywords: Barium, cobalt, erbium, oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On a New Observed Dimorphism of BaCoEr2O5Single crystals of BaCoEr2O5 were prepared by CO2-LASER technique under N2-atmosphere and investigated by X-ray single crystal methods. It crystallizes with orthorhombic symmetry, space group D2h16-Pnma (a = 12.2787, b = 5.6826, c = 7.0344 Å; Z = 4). The so far unknown crystal structure of BaCoEr2O5 belongs to the BaCuLn2O5 type forming the dimorphic substance to the previously described Ni type of BaCoEr2O5.
    Notes: BaCoEr2O5 wurde mit CO2-LASER-Technik in Stickstoffatmosphäre einkristallin dargestellt und röntgenographisch untersucht. Es kristallisiert orthorhombisch, Raumgruppe D2h16-Pnma, mit den Gitterkonstanten a = 12,2787, b = 5,6826, c = 7,0344 Å; Z = 4. Die hier untersuchten Einkristalle von BaCoEr2O5 gehören zum BaCuLn2O5-Typ und bilden die dimorphe Form zum früher beschrieben Ni - Typ von BaCoEr2O5.
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  • 72
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    Zeitschrift für anorganische Chemie 619 (1993), S. 476-488 
    ISSN: 0044-2313
    Keywords: Dialkali metal dichalcogenides ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Dialkali Metal Dichalcogenides β-Na2S2, K2S2, α-Rb2S2, β-Rb2S2, K2Se2, Rb2Se2, α-K2Te2, β-K2Te2 and Rb2Te2The first presentation of pure samples of α- and β-Rb2S2, α- and β-K2Te2, and Rb2Te2 is described. Using single crystals of K2S2 and K2Se2, received by ammonothermal synthesis, the structure of the Na2O2 type and by using single crystals of β-Na2S2 and β-K2Te2 the Li2O2 type structure will be refined. By combined investigations with temperature-dependent Guinier-, neutron diffraction-, thermal analysis, and Raman-spectroscopy the nature of the monotropic phase transition from the Na2O2 type to the Li2O2 type will be explained by means of the examples α-/β-Na2S2 and α-/β-K2Te2. A further case of dimorphic condition as well as the monotropic phase transition of α- and β-Rb2S2 is presented. The existing areas of the structure fields of the dialkali metal dichalcogenides are limited by the model of the polar covalence.
    Notes: Die erstmalige Darstellung phasenreiner Proben von α- und β-Rb2S2, von α- und β-K2Te2 und von Rb2Te2 wird beschrieben. Mit Hilfe von ammonothermal synthetisierten Einkristallen des K2S2 und des K2Se2 wird die Struktur des Na2O2-Typs, mit Einkristallen des β-Na2S2 und des β-K2Te2 die des Li2O2-Typs verfeinert. Durch kombinierte temperaturabhängige Guinier-, Neutronenbeugungs-, thermoanalytische und Raman-spektroskopische Untersuchungen wird die Natur des monotropen Phasenübergangs vom Na2O2-Typ zum Li2O2-Typ an Hand der Beispiele α-/β-Na2S2 und α-/β-K2Te2 aufgeklärt. Ein weiterer Fall von Dimorphie, der ebenfalls monotrope Übergang von α-Rb2S2(Rb2O2-Typ) zu β-Rb2S2(Na2O2-Typ), wird vorgestellt. Die Existenzgebiete der Strukturfelder bei den Dialkalimentalldichalkogeniden werden mittels des Modells der polaren Kovalenz gegeneinander abgegrenzt.
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  • 73
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    Zeitschrift für anorganische Chemie 619 (1993), S. 521-524 
    ISSN: 0044-2313
    Keywords: Calcium ; bismuth ; vanadium ; oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of CaBiVO5Single crystals of the hitherto unknown compound CaBiVO5 were prepared and investigated by X-ray work. It crystallizes with orthorhombic symmetry, space group D2h15—Pbca, a = 11.2022, b = 5.4283, c = 15.5605 Å, Z = 8. The crystal structure is characterized by layers of the edge-linked CaO7 polyhedra, isolated VO4 tetrahedra and an asymmetric surrounding of Bi3+ by oxygen.
    Notes: Die bisher unbekannte Verbindung CaBiVO5 wurde einkristallin dargestellt und röntgenographisch untersucht. Sie kristallisiert orthorhombisch in der Raumgruppe D2h15-Pbca mit a = 11,2022, b =5,4283, c = 15,5605 Å, Z = 8. Die Kristallstruktur ist durch Schichten aus CaO7-Polyedern, isolierte VO4-Tetraeder und asymmetrisch koordinierte Bi3+-Ionen charakterisiert.
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  • 74
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    Zeitschrift für anorganische Chemie 619 (1993), S. 529-533 
    ISSN: 0044-2313
    Keywords: Barium-zinc-rare earth metal-oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Compounds with Zinc in Square Pyramidal Coordination: BaZnDy2O5 and Ba1.25ZnHo2O5.25 (Ba5Zn4Ho8O21).Single crystals of (I): BaZnDy2O5 and (II): Ba5Zn4Ho8O21 were prepared by high temperature reactions and investigated by X-ray technique. (I) belongs to the BaCuLn2O5 type, space group D2h16-Pbnm; a = 7.084; b = 12.368; c = 5.728 Å, Z = 4. (II) is isotypic to Ba5Mn4Ln8O21, space group C4h5-I4/m; a = 13.779; c = 5.707 Å, Z = 2. The two different structure types are caused by the small difference in the composition of 0.25 BaO. Analogies and differences will be discussed. In addition the lattice constants of powder samples of Ba5Zn4Ln8O21 (Ln = Eu, Gd, Dy, Ho, Er and Y) are given.
    Notes: Mit Hochtemperaturreaktionen wurden Einkristalle von (I): BaZnDy2O5 und (II): Ba5Zn4Ho8O21 dargestellt und röntgenographisch untersucht. (I) gehört zum BaCuLn2O5-Typ, Raumgruppe D2h16-Pbnm mit a = 7,084; b = 12,368; c = 5,728 Å, Z = 4. (II) ist isotyp zum Ba5Mn4Ln8O21-Typ, Raumgruppe C4h5-I4/m, mit a = 13,779; c = 5,707 Å, Z = 2. Der geringe Unterschied von 0,25 BaO führt zu zwei verschiedenen Strukturtypen. Gemeinsamkeiten und Unterschiede werden diskutiert. Weitere Verbindungen vom Typ Ba5Zn4Ln8O21 mit Ln = Eu, Gd, Dy, Ho, Er und Y wurden mikrokristallin dargestellt und die Gitterkonstanten bestimmt.
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  • 75
    ISSN: 0044-2313
    Keywords: Barium ; indium ; zinc ; oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Structure of Ba3In2Zn5O11. An Oxoindate/zincatesol;zincate with Zn10O20 and In4O16 Macropolyhedra with Zn2+ in Tetrahedral Coordination by O2-Ba3In2Zn5O11 was prepared for the first time by a flux technique and investigated by single crystal X-ray work. It crystallizes with cubic symmetry, space group T2d-F43m, a = 13.3588 Å, Z = 8. Zn2+ show tetrahedral coordination by O2-, forming Zn10O20 macropolyhedra. In addition the nZn/Osol;O part of the crystal structure is made up of Zn10O20 parts. Edge connection of four InO6 octahedra results in In4O16 groups. The crystal structure will be shown and discussed.
    Notes: Mit einer Schmelzmitteltechnik wurde erstmals Ba3In2Zn5O11 dargestellt und an Einkristallen röntgenographisch untersucht. Es kristallisiert kubisch, in der Raumgruppe T2d-F43m, mit a = 13,3588 Å und Z = 8. Zn2+ ist tetraedrisch von O2- koordiniert und bildet Zn10O20-Makropolyeder. Ferner wird der nZn/Osol;O-Teil der Kristallstruktur aus Zn10O20-Bausteinen zusammen-gesetzt. Die oktaedrisch koordinierten In3+-Ionen verknüpfen über Kanten zu In4O16-Baugruppen. Die Kristallstruktur wird vorgestellt und diskutiert.
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  • 76
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    Zeitschrift für anorganische Chemie 619 (1993), S. 617-620 
    ISSN: 0044-2313
    Keywords: Potassium ; magnesium ; copper ; vanadium ; oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Potassium Magnesium Oxocuprate/-vanadate: KMg2Cu2V3O12.Single crystals of KMg2Cu2V3O12 were prepared by solid state reactions below the melting point of the reaction mixture (K2CO3, MgCO3, CuO, V2O5). It crystallizes with monoclinic symmetry space group C2h6—C2/c, a = 12.1592 Å, b = 12.7204 Å, c = 6.8557 Å, β = 111.73°, Z = 4. The structure type is characterized by VO4 tetrahedra, twisted CuO4 square units, MgO6 octahedra and a special 2 + 4 + 2 coordination around the potassium ion.
    Notes: Einkristalle von KMg2Cu2V3O12 wurden durch Feststoffreaktionen, dicht unterhalb des Schmelzpunktes des Reaktionsgemenges (K2CO3, MgCO3, CuO, V2O5), erhalten. Die Verbindung kristallisiert mit monokliner Symmetrie, Raumgruppe C2h6—C2/c, a = 12,1592 Å, b = 12,7204 Å, c = 6,8557 Å, β = 111,73°, Z = 4. Die Kristallstruktur ist durch VO4-Tetraeder, tordierte CuO4-Baugruppen, MgO6-Oktaeder und Kalium, in einer besonderen 2 + 4 + 2 Koordination charakterisiert.
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  • 77
    ISSN: 0044-2313
    Keywords: Niobum bromides ; (Nb6Br18) units ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Kristallchemie einiger neuer Niobbromide mit (Nb6Br18)-Einheiten: Die Strukturen von CsErNb6Br18 und Cs2EuNb6Br18.Zwei neue Reihen von Nb6-Bromiden, CsSENb6Br18 (SE = alle Lanthanoide außer Eu und Yb, + Y) (Typ H) und M2SENb6Br18 (M = Cs, Rb, Tl; SE = Eu, Yb) (Typ R) sind dargestellt worden. Die Kristallstrukturen von CsErNb6Br18 und Cs2EuNb6Br18, isotyp mit den entsprechenden Chloriden, wurden durch Einkristall-Röntgendaten bestimmt. Die Stabilität der (Nb6Br18)-Einheit hängt von der Art und der Ladung des Gegenkations ab. Ein Vergleich zwischen den entsprechenden Reihen der Chloride und Bromide wird anhand der chemischen Eigenschaften und der Größe des Halogens diskutiert.
    Notes: Two new series of Nb6 bromides, CsRENb6Br18 (RE = all the lanthanides excepted Eu and Yb, + Y) (type H) and M2RENb6Br18 (M = Cs, Rb, Tl; RE = Eu, Yb) (type R) have been isolated. The crystal structures of CsErNb6Br18 and Cs2EuNb6Br18, isotypic with the corresponding chlorides, have been determined by single crystal X-ray diffraction data. The (Nb6Br18) intra-unit strength is related to the nature and the charge of the counter cation. A comparison between the corresponding chlorides and bromides series, based on the chemical properties and the size of the halogen is discussed.
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  • 78
    ISSN: 0044-2313
    Keywords: Silver vanadium bronze ; copper vanadium bronze ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Novel Means of Synthesis for Vanadium Bronzes. Crystal Structure of β—Ag0.33V2O5. Refinement of the Crystal Structure of ∊—Cu0.76V2O5Ag0.33V2O5 and Cu0.76V2O5 were obtained by heating equimolar mixtures of AgI + V2O5 (700°C) and CuI + V2O5 (525°C), respectively, in sealed quartz glass ampoules. In each case, one of the well-formed crystals served for an X-ray structure analysis. Ag0.33V2O5 has the structure known of the β phase of the vanadium bronzes, i. e. layers of edge-sharing, distorted VO6 octahedra are liked by certain common octahedron vertices, the Ag atoms randomly occupy two positions with occupation probabilities of 0.5. Cu0.76V2O5 has the previously determined structure of the ∊ phase, however, its space group is not Cm but C2/m.
    Notes: Ag0,33V2O2 und Cu0,76V2O5 wurden durch zweiwöchiges Erhitzen von äquimolaren Gemischen AgI + V2O5 (700°C) bzw. CuI + V2O (525°C) in einer Quarzglasampulle erhalten. Mit je einem der gut ausgebildeten Kristalle wurden eine Röntgenstrukturanalyse durchgeführt. Ag0,33V2O5 hat die für die β-Phase der Vanadiumbronzen bekannte Struktur, d. h. Schichten aus verzerrten, kantenverknüpften VO6-Oktaedern sind über bestimmte Oktaederecken verknüpft, die Ag-Atome nehmen statistisch zwei Atomlagen der Koordinationszahl 7 mit halber Besetzungswahrscheinlichkeit ein. Cu0,76V2O5 hat die früher bereits bestimmte Struktur der ∊-Phase, deren Raumgruppe jedoch nicht Cm sondern C2/m ist.
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  • 79
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    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 281-286 
    ISSN: 0044-2313
    Keywords: Tetraphosphorus hexaoxide disulfide and trisulfide ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Improved Syntheses, Crystal Growth, and Crystal Structure Determination of P4O6S2 and P4O6S3Syntheses and single crystal growths of the title compounds are described. Both compounds crystallize in the space group P21/c (P4O6S2: a = 11.293(4); b = 6.457(3); c = 11.588(4) Å; β = 90.29(2)°, 2 450 diffractometer data, Rw = 0.035/P4O6S3: a = 15.611(5); b = 8,303(3); c = 9.697(4) Å; β = 127.12(2)°, 2 481 diffractometer data, Rw = 0.034). The structural data for the series P4O6Sn (n = 1 - 4) thus completed are compared to their oxide analogues P4O6On (n = 1 - 4). The changes in the geometry of the P4O6-cage in course of its successive oxidation are discussed.
    Notes: Darstellung und Einkristallzucht der Titelverbindungen werden beschrieben. Beide Verbindungen kristallisieren in der Raumgruppe P21/c (P4O6S2: a = 11,293(4); b = 6,457(3); c = 11,588(4) Å; β = 90,29(2)°, 2 450 Diffraktometerdaten, Rw = 0,035/P4O6S3: a = 15,611(5); b = 8,303(3); c = 9.697(4) Å; β = 127,12(2)°, 2 481 Diffraktometerdaten, Rw = 0,034). Durch die neu gelösten Strukturen werden die Daten für das System P4O6Sn (n = 1 - 4) komplettiert und können mit denen der analog aufgebauten Oxide P4O6On (n = 1 - 4) verglichen werden. Die Veränderungen der Molekülgeometrie des zentralen P4O6-Käfigs im Zuge der schrittweisen Oxidation werden diskutiert.
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  • 80
    ISSN: 0044-2313
    Keywords: Lithium thioborates ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Li5B7S13 and Li9B19S33: Two Lithium Thioborates with Novel Highly Polymeric Anion NetworksLi5B7S13 (C2/c; a = 17.304(2) Å, b = 21.922(3) Å, c = 12.233(2) Å, β = 134.91(1)°; Z = 8) and Li9B19S33 (C2/c; a = 23.669(9) Å, b = 14.361(3) Å, c = 12.237(3) Å, β = 103.77(2)°; Z = 4) were prepared by reaction of stoichiometric amounts of lithium sulfide, boron, and sulfur at 750°C (Li5B7S13) and 700°C (Li9B19S33) with subsequent annealing. The crystal structures consist of interpenetrating, polymeric boron sulfur anion networks which are formed by corner-sharing of B4S10 and B10S20 units (Li5B7S13), or B19S36 units (Li9B19S33). The lithium cations are situated in between with a strong disorder in Li9B19S33.
    Notes: Li5B7S13 (C2/c; a = 17,304(2) Å, b = 21,922(3) Å, c = 12,233(2) Å, β = 134,91(1)°; Z = 8 und Li9B19S33 (C2/c; a = 23,669(9) Å, b = 14,361(3) Å, c = 12,237(3) Å, β = 103,77(2)°; Z = 4 wurden durch Reaktion von stöchiometrischen Mengen Lithiumsulfid, Bor und Schwefel bei 750°C (Li5B7S13) und 700°C (Li9B19S33) mit anschließendem Tempern dargestellt. Die Kristallstrukturen bestehen aus sich durchdringenden, polymeren Bor-Schwefel-Anionengerüsten, die durch Eckenverknüpfung von B4S10- und B10S20-Einheiten (Li5B7S13) bzw. B19S36-Einheiten (Li9B19S33) gebildet werden. Dazwischen befinden sich die Lithiumkationen, wobei bei Li9B19S33 eine starke Fehlordnung beobachtet wird.
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  • 81
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 517-520 
    ISSN: 0044-2313
    Keywords: Alkaline Earth ; ruthenium ; oxygen ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Novel Oxoruthenates of the 6 L-Perovskite Type: Ba3SrRu2-xTaxO9 (x = 0.8 and 1.4) with a Comment on Ba3CaRu2O9Single crystals of the phases Ba3SrRu2-xTaxO9 [(I): x = 0.8 and (II): x = 1.4] and the compound (III): Ba3CaRu2O9 were prepared by a BaCl2 flux and investigated by X-ray methods. (I)-(III) crystallizes with hexagonal symmetry space group P62c with lattice constants: (I) a = 6.003 Å; c = 15.227 Å; (II) a = 5.988 Å; c = 15.220 Å and (III) a = 5.891 Å; c = 14.571 Å. The crystal structures of these substances corresponds to the 6 layer perovskites with the stacking sequence (hcc)2. All of them show a so far not described slightly distorted oxygen framework caused by the Sr2+ and Ca2+ ions.
    Notes: Einkristalle der Phasen Ba2SrRu2-xTaxO9 [(I): x = 0,8 und (II): x = 1,4] sowie der Verbindung (III): Ba3CaRu2O9 wurden in einer BaCl2-Schmelze präpariert und mit Hilfe von Röntgenbeugungsmethoden untersucht. (I)-(III) kristallisieren in der hexagonalen Raumgruppe P62c mit den Gitterkonstanten: (I) a = 6,003 Å; c = 15,227 Å; (II) a = 5,988 Å; c = 15,220 Å und (III) a = 5,891 Å; c = 14,571 Å. Ihre Kristallstrukturen entsprechen den 6 L-Perowskiten mit der Stapelsequenz (hcc)2. Sie zeigen eine bislang noch nicht beschriebene leichte Verzerrung im Aufbau der Sauerstoffteilgitter, die auf die Sr2+ - bzw. Ca2+-Ionen zurückgeführt werden kann.
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  • 82
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 525-528 
    ISSN: 0044-2313
    Keywords: Barium-bismuth-oxovanadate ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ba2BiV3O11 containing Bismuth within closed CoordinationA new barium bismuth oxovanadate, Ba2BiV3O11, was prepared and investigated by X-Ray single crystal technique. It crystallizes with monoclinic symmetry space group C2h5 - P21/a, lattice constants a = 24.6473; b = 7.7347; c = 5.6375 Å, β = 103.16°; Z = 4. Octahedra arround Bi3+, tetrahedra and double tetrahedra arround V5+ form a tunnel structure. The tunnel positions are occupied by Ba(2).
    Notes: Ein neues Barium-Bismutoxovanadat, Ba2BiV3O11, wurde einkristallin dargestellt und röntgenographisch untersucht. Es kristallisiert monoklin, Raumgruppe C2h5 - P21/a, mit den Gitterkonstanten a = 24,6473; b = 7,7347; c = 5,6375 Å, β = 103,16°; Z = 4. Oktaeder um Bi3+, Tetraeder und Doppeltetraeder um V5+ vernetzen mit Ba(1) zu einer Tunnelstruktur. Ba(2) besetzt die Tunnelpositionen.
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  • 83
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 534-536 
    ISSN: 0044-2313
    Keywords: Calcium ; iridium ; copper ; oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Ca3IrCuO6Single crystals of Ca3IrCuO6 were prepared by a flux technique and investigated by single crystal X-ray work. It crystallizes with monoclinic symmetry, space group C2h6 - C12/c1; a = 9.032, b = 9.295, c = 6.466 Å, β = 91.35°, Z = 4. Ca3IrCuO6 is isotypic to Sr3IrCuO6. The square planare CuO4 polygones show probably a slightly deficit accompanied by an adequate part of iridium in the oxydation state Ir5+.
    Notes: Einkristalle von Ca3IrCuO6 wurden mit Hilfe von Schmelzmitteln dargestellt und röntgenographisch untersucht. Es kristallisiert mit monokliner Symmetrie in der Raumgruppe C2h6 - C12/c1, mit a = 9,032, b = 9,295, c = 6,466 Å, β = 91,35°, Z = 4. Ca3IrCuO6 ist mit Sr3IrCuO6 isotyp. Die planaren CuO4-Baugruppen zeigen wahrscheinlich ein geringes Defizit an Cu2+, welches durch einen adäquaten Teil von Ir5+ kompensiert wird.
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  • 84
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 537-539 
    ISSN: 0044-2313
    Keywords: Sodium-barium-oxo/peroxo-aurate(III) ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the first Alkaline-Alkaline-Earth-Oxo/Peroxo-Aurate(III): NaBa4AuO4(O2)2The hitherto unknown compound NaBa4AuO4(O2)2 was prepared by oxidizing of barium gold alloy with Na2O2 in closed Ag-bombs. X-ray single crystal investigation led to tetragonal symmetry space group D4h17I4/mmm, a = 5.939; c = 15.393 Å, Z = 2. NaBa4AuO4(O2)2 shows a distorted square antiprismatic surrounding of Ba2+ by four peroxo groups on one side and four O2- on the opposite. Au3+ shows the usual square planar polygons of AuO4. Na+ is coordinated by four O2- ions in the base of an octahedron and two peroxo groups in the apical positions.
    Notes: Die bisher unbekannte Verbindung NaBa4AuO4(O2)2 wurde durch Reaktion einer Barium-Gold-Legierung mit Na2O2 im geschlossenen Silberbömbchen dargestellt. Die Kristallstruktur wurde röntgenographisch an Einkristallen untersucht. NaBa4AuO4(O2)2 kristallisiert tetragonal, Raumgruppe D4h17-I4/mmm, a = 5,939; c = 15,393 Å, Z = 2. Ba2+ ist verzerrt quadratisch antiprismatisch von vier Peroxogruppen auf der einen und vier O2--Ionen auf der Gegenseite koordiniert. Au3+ zeigt quadratisch planare Koordination von O2- und Na+ ist von vier O2--Ionen in der Oktaederbasisfläche und zwei Peroxogruppen in trans-Stellung dazu koordiniert.
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  • 85
    ISSN: 0044-2313
    Keywords: Tris(tri-tert-butylsilyl)heptaphosphonortricyclane P7(t-Bu3Si)3 ; synthesis ; 31P{1H} NMR data ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Characterization, and Structure of P7(t-Bu3Si)3 („Tris(supersilyl)heptaphosphane(3)“Tris(tri-tert-butylsilyl)heptaphosphanortricyclane P7(t-Bu3Si)3 1 is obtained from the reaction of (t-Bu)3Si—Si(t-Bu)3 with white phosphorus and forms colorless to pale yellow thermostable crystals. 1 is identified by the complete analysis of its 31P{1H} NMR spectrum (A[MX]3 spin system) as well as by a single crystal structure determination (space group Pca21, a = 170.76(2)pm, b = 131.14(3)pm, c = 426.61(5)pm, α = β = γ= 90°, Z = 8 formula units in the elementary cell). The steric demand of the (t-Bu)3Si-Groups causes an increase of the exocyclic bond angles at the equatorial phosphorus atoms Pe, while it does not particularly influence the P7-skeleton. Chlorine (r.t.) and bromine (70°C) degrade the P7-cage of 1 with formation of PX3 and (t-Bu)3SiX (X = Cl, Br).
    Notes: Tris(tri-tert-butylsilyl)-heptaphosphanortricyclan P7(t-Bu3Si)3 1 entsteht durch Umsetzung von (t-Bu)3Si—Si(t-Bu)3 mit weißem Phosphor und bildet farblose bis blaßgelbe thermostabile Kristalle. Die Identität von 1 wird durch die vollständige Analyse des 31P{1H}-NMR-Spektrums (A[MX]3-Spinsystem) sowie durch eine Kristallstrukturbestimmung belegt. 1 kristallisiert in der Raumgruppe Pca21 mit Z = 8 Formeleinheiten; a = 170,76(2)pm, b = 131,14(3)pm, c = 426,61(5)pm, α = β = γ= 90°. Der erhöhte Raumbedarf der (t-Bu)3Si-Gruppen führt zu einer Aufweitung der exocyclischen Bindungswinkel an den äquatorialen Phosphoratomen Pe ohne das P7-Gerüst besonders zu beeinflußen. Chlor (Raumtemperatur) und Brom (70°C) bauen den P7-Käfig von 1 unter Bildung von PX3 und (t-Bu)3SiX (X = Cl, Br,) ab.
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  • 86
    ISSN: 0044-2313
    Keywords: Aluminum sulfide ; crystal structure ; chemical transport ; five-coordinated aluminum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of a Novel Hexagonal Modification of Al2S3 with Five-coordinated AluminumA new hexagonal high temperature modification of Al2S3 could be prepared by chemical vapour transport with iodine (860 → 750°C) or by annealing of α -Al2S3 at 550°C. According to the single crystal X-ray structure determination the novel form of Al2S3 crystallizes in space group P 61 (No. 169) with a = 6.491(1), c = 17.169(4) Å, V = 626.5 Å3, Z = 6; R = 0.0253. In this modification one half of the aluminum atoms are tetrahedrally coordinated [d(Al—S): 2.226-2.267 Å], whereas the other half are in trigonal bipyramidal coordination of five S atoms with bond lengths of 2.272-2.315 Å (equatorial) and 2.495-2.521 Å (axial).Aluminum in AlS5 coordination is observed for the first time in this compound. The crystal structure is isotypic to In2Se3 and AlInS3. In addition, results of a refinement of the α -Al2S3 crystal structure are reported which were obtained on crystals prepared also by chemical vapour transport with iodine.
    Notes: Eine bisher noch nicht beschriebene hexagonale Hochtemperatur-Modifikation von Al2S3 konnte in reiner Form entweder durch chemischen Transport mit Iod (860 → 750°C) oder durch Tempern von α -Al2S3 oberhalb 550°C erhalten und durch eine Einkristall-Röntgenstrukturanalyse charakterisiert werden.Die neue Form des Al2S3 kristallisiert in der Raumgruppe P 61 (Nr. 169) mit a = 6,491(1), c = 17,169(4) Å, V = 626,5 Å3, Z = 6; R = 0,0253. In dieser Modifikation liegt die eine Hälfte der Aluminiumatome tetraedrisch koordiniert vor [d(Al—S): 2,226-2,267 Å], während die andere Hälfte trigonal-bipyramidal von fünf S-Atomen mit Al—S-Bindungslängen von 2,272 bis 2,315 Å (äquatorial) und 2,495-2,521 Å (axial) umgeben ist.Aluminium in AlS5-Koordination ist bisher unbekannt und wird hier zum ersten Mal beobachtet. Die Struktur ist isotyp zu In2Se3 und AlInS3. Zusätzlich wird über die Verfeinerung der Kristallstruktur α von -Al2S3 an Einkristallen berichtet, die ebenfalls durch chemischen Transport mit Iod hergestellt wurden.
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  • 87
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1004-1006 
    ISSN: 0044-2313
    Keywords: Alkaline-Earth ; palladium ; oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On an Alkaline-Earth Oxopalladate containing Pd6O12 Rings: CaBa2Pd3O6CaBa2Pd3O6 was prepared for the first time and investigated by X-ray single crystal technique. It is isotypic to NaBa2Cu3O6 and crystallizes with orthorhombic symmetry, space group D2h23-Fmmm, a = 8.717, b = 11.47, c = 14.933 Å; Z = 2. Typical features of the crystal structure are edge connected square planar PdO4 polygones, forming isolated Pd6O12 rings.
    Notes: CaBa2Pd3O6 wurde erstmals dargestellt und röntgenographisch an Einkristallen untersucht. Es ist isotyp mit NaBa2Cu3O6 und kristallisiert mit orthorhombischer Symmetrie, Raumgruppe D2h23-Fmmm, a = 8,717, b = 11,47, c = 14,933 Å; Z = 2. Charakteristische Strukturmerkmale sind kantenverknüpfte planare PdO4-Polygone, die isolierte Pd6O12-Ringe ausbilden.
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  • 88
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1012-1016 
    ISSN: 0044-2313
    Keywords: Zwitterionic λ5-organofluorosilicate ; pentacoordinate silicon ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal and Molecular Structure of Tetrafluoro[2-(pyrrolidinio)ethyl]silicateThe zwitterionic tetrafluoro[2-(pyrrolidinio)ethyl]silicate (4) was synthesized by reaction of trimethoxy(2-pyrrolidinoethyl)silane (5) with hydrogen fluoride in ethanol/hydrofluoric acid at 0°C. The crystal and molecular structure of 4 was studied at -100°C by single-crystal X-ray diffraction. In addition, 4 was characterized by solution-state NMR studies (CD3CN: 1H, 13C).
    Notes: Das zwitterionische Tetrafluoro[2-(pyrrolidinio)ethyl]silicat (4) wurde durch Reaktion von Trimethoxy(2-pyrrolidinoethyl)silan (5) mit Fluorwasserstoff in einem Ethanol/Flußsäure-Gemisch bei 0°C synthetisiert. Die Kristall- und Molekülstruktur von 4 wurde bei - 100°C mittels einer Einkristall-Röntgenstrukturanalyse untersucht. Außerdem wurde 4 durch NMR-Untersuchungen in Lösung charakterisiert (CD3CN: 1H, 13C).
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  • 89
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1017-1022 
    ISSN: 0044-2313
    Keywords: Thallium perrhenate ; room-temperature modification ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Kristallstruktur von β-ThalliumperrhenatDie Raumtemperaturmodifikation von Thalliumperrhenat, β-TlReO4, wurde durch Röntgenbeugung an Einkristallen untersucht. β-TlReO4 kristallisiert in der monoklinen Raumgruppe P1121/a mit a = 5,636(1), b = 17,428(3), c = 13,353(3) Å, γ = 89,86(2)° und Z = 12. Die Strukturverfeinerung endete bei R = 0,063 (wR = 0,053), wobei 2 020 absorptionskorrigierte Reflexdaten verwendet wurden. β-TlReO4 läßt sich als eine Verwachsung von β-CsReO4- und Scheelit-Einheiten auf Elementarzellniveau beschreiben.Die Struktur von β-TlReO4, besteht aus isolierten ReO4-Tetraedern, die durch TlO8- und TlO9-Polyeder miteinander verknüpft sind. Auf der Basis gruppentheoretischer Überlegungen werden die strukturellen Beziehungen zwischen β-TlReO4, β-CsReO4, α-CsReO4 und Scheelit-Typ diskutiert.
    Notes: β-TlReO4, the room temperature modification of thallium perrhenate, has been investigated by means of single crystal X-ray diffraction. It crystallizes in the monoclinic space group P1121/a with a = 5.636(1), b = 17.428(3), c = 13.353(3) Å, γ = 89.86(2)° and Z = 12. The structure has been refined to R = 0.063 (wR = 0.053) using 2 020 absorption-corrected reflections. The title compound can be described as an intergrowth of β-CsReO4 and scheelite type blocks at unit cell level. The structure of β-TlReO4 consists of isolated ReO4 tetrahedra linked together by TlO8 and TlO9 polyhedra. Based upon group theoretical considerations the structural relationships between β-TlReO4, β-CsReO4, α-CsReO4 and scheelite type are discussed.
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  • 90
    ISSN: 0044-2313
    Keywords: Polysulfonyl amines ; silver(1) dimesylarnide ; tetrakis(dimesylamido)aquatetrasilver(l) ; crystal structure ; thermal analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polysulfonyl Amines. XLI. A Silver(I) Hydrate with an Unusual Composition: Characterization of Tetrakis(dimesylamido)aquatetrasilver(I) [Ag4(N)SO2CH3)2}4(H2O)] by X-Ray Diffraction and Thermal AnalysisThe title compound is obtained by crystallizing AgN(SO2CH3)2 from water at room temperature. Crystallographic data (at -95°C): Triclinic space group P1, a = 864.6(4), b = 1 211.2(5), c = 1 399.1(5) pm, α = 90.97(3), β = 90.90(3), γ = 98.25(4)°, V = 1.4496 nm3, Z = 2, Dx = 2.608 Mg m-3. The four independent silver atoms and the water molecule form zigzag chains Ag(1)-Ag(2)-(μ-H2O)-Ag(3) … Ag(4) … Ag(1′) with distances Ag(1)-Ag(2) 309.7, Ag(2)-O(w) 241.8, O(w)-Ag(3) 241.4, Ag(3) … Ag(4) 342.9, Ag(4) … Ag(1′) 361.4 pm. The catenated silver atoms are further connected by the dimesylamide anions acting as tridentate bridging (α-O, N, ω-O)-ligands. The resulting strands are interconnected into layers through one O(S)-Ag′ contact (247 pm) and one hydrogen bond O(w)-H(l) … O′(S) per repeating unit. Between the layers, a weak O(S) … Ag″ interaction (271 ptn) and a hydrogen bond O(w)-H(2) … O(S) per repeating unit are observed. The silver atoms Ag(l) to Ag(4) display the coordination numbers 5 [NO,Ag(2), distorted trigonal bipyramid], 5[NO2,O(w)Ag(I), distorted trigonal bipyramid], 5[O4,O(w), trigonal bipyramid], and 2 + 1 (N2, li-near; plus a secondary Ag … 0 contact). The dehydration of the title compound and a solid-solid phase transformation in anhydrous AgN(SO2CH3)2, were quantitatively investigated by thermoconductometry and time- and temperature-resolved X-ray diffractometry (TXRD).
    Notes: Die Titelverbindung entsteht durch Kristallisation von AgN(SO2CH3)2 aus Wasser bei Raumtemperatur. Kristallographische Daten (bei -95°C): Trikline Raumgruppe P1, a = 864,6(4), b = 1 211,2(5), c = 1 399,1(5) pm, α = 90,97(3), β = 90,90(3), γ = 98,25(4)°, V = 1,4496 nm3, Z = 2, Dx = 2,608 Mg m-3. Die vier unabhängigen Silberatome und das Wassermolekül bilden Zickzack-Ketten Ag(1)-Ag(2)-(μ-H2O)-Ag(3) … Ag(4) … Ag(1′) mit den Abständen Ag(1)-Ag(2) 309,7, Ag(2)-O(W) 241,8 O(W)-Ag(3) 241,4, Ag(3) … Ag(4) 342,9, Ag(4) … Ag(1′) 361,4 pm. Die Silberatome in der Kette werden durch die Dimesylamid-Anionen miteinander verklammert, die innerhalb der so resultierenden Stränge als dreizähnig-verbrückende (α-O, N, ω-O)-Liganden wirken. Die Stränge sind pro Repetiereinheit durch einen Kontakt O(S)-Ag′ (247 pm) und eine Wasserstoffbrücke O(W)-H(1) …O′(S) zu Schichten verknüpft. Zwischen den Schichten bestehen je Strang-Repetiereinheit eine schwache Wechselwirkung O(S) … Ag″ (271 pm) und eine Wasserstoffbrücke O(W)-H(2) … O″(S). Die Silberatome besitzen in der Reihenfolge Ag(1) bis Ag(4) die Koordinationszahl 5 [NO3Ag(2), verzerrt trigonal-bipyramidal], 5 [NO2O(W)Ag(1), verzerrt trigonal-bipyramidal], 5 [O4O(W), trigonal-bipyramidal], 2 + 1 (N2, linear; ein zusätzlicher Sekundärkontakt Ag … O). Die Dehydratation der Titelverbindung und eine fest-fest-Phasenumwandlung des wasserfreien AgN(SO2CH3)2 wurden durch Thermokonduktometrie sowie zeit- und temperaturaufgelöste Röntgendiffraktometrie (TXRD) quantitativ untersucht.
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  • 91
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1037-1046 
    ISSN: 0044-2313
    Keywords: Nickel ; chromium ; molybdenum ; penicillamine ; complexes ; synthesis ; crystal structure ; antidot ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Penicillamine Complexes of Nickel, Chromium, and Molybdenum  -  Structural Particularity and Biological/Medical RelevanceThe compounds Tl2[NiII(H2O)6][NiII(D-pen)(L-pen)]2[NiII(SCN)2(H2O)4] 1, Tl[NiII(D-pen)2H] · H2O 2, Tl[CrIII(D-pen)2] 3, and Na2[Mo2VO4(pen)2] · 3 CH3OH · 3 H2O 4 have been prepared by the reaction of nickel nitrate (for 1), nickel acetate (for 2), potassium chromate (for 3), and sodium molybdate (for 4) with D- and D, L-penicillamine, respectively. They were characterized by single-crystal X-ray structure analysis and other physical methods. Whereas penicillamine acts as a bidentate (N, S)-ligand in 1 and 2, CrIII (in 3), and MoV (in 4) are coordinated to the three ligand atoms N, O, and S. The presence of three different types of NiII-complexes a cationic, a neutral, and an anionic one in 1 is remarkable.For crystal data see Inhaltsübersicht.
    Notes: Die Verbindungen Tl2[NiII(H2O)6][NiII(D-Pen)(L-Pen)]2[NiII(SCN)2(H2O)4] 1, Tl[NiII(D-Pen)2H] · H2O 2, Tl[CrIII(D-Pen)2] 3 und Na2[Mo2VO4(Pen)2] · 3 CH3OH · 3 H2O 4 wurden durch Umsetzung von Nickelnitrat (für 1), Nickelacetat (für 2), Kaliumchromat (für 3) und Natriummolybdat (für 4) mit D- bzw. D, L-Penicillamin in wäßriger Lösung dargestellt und durch Einkristallstrukturanalyse und andere physikalische Methoden charakterisiert. Während in den Ni-Pen-Komplexen von 1 und 2 Penicillamin als zweizähniger Ligand (N, S) fungiert, sind CrIII in 3 und MoV in 4 über N, O und S koordiniert. Bemerkenswert ist, daß in 1 drei verschiedene Ni-Komplexe und zwar ein kationischer, ein neutraler und ein anionischer in einer Elementarzelle vorliegen.1: C2/m, a = 1 484,6(4), b = 1 358,7(4), c = 1 204,7(3) pm, β = 103,75(2)°, V = 2 360,4(11) ° 106 pm3, R = 0,042 für 1 633 unabhängige Reflexe (Fo〉 4,0σ(Fo)), Z = 2.2: C2, a = 2 279,9(7), b = 613,1(1), c = 1 275,2(3) pm, β = 110,94(2)°, V = 1 664,8(6) · 106 pm3, R = 0,056 für 1 413 unabhängige Reflexe (Fo〉 4,0σ(Fo)), Z = 4.3: C2, a = 2 054,0(3), b = 592,1(1), c = 606,7(1) pm, β = 92,89(1)°, V = 736,95(17) · 106 pm3, R = 0,028 für 862 unabhängige Reflexe (Fo〉 4,0σ(Fo)), Z = 2.4: P1, a = 996,2(4), b = 1 222,2(7), c = 1 395,3(7) pm, = 114,27(4), β = 104,55(4), γ = 95,63(4)°, V = 1 459,4(13) · 106 pm3, R = 0,072 für 3 763 unabhängige Reflexe (Fo〉 4,0σ(Fo)), Z = 2.
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  • 92
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1073-1082 
    ISSN: 0044-2313
    Keywords: Bismuth arene π-complexes ; bismuth xylene complexes ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heavy Metal π-Complexes. IX. The Chain Polymers ∞1[(1,2- (CH3)2C6H4BiCl3)2], ∞1[(1,3- (CH3)2C6H4BiCl3)2] and ∞1[(1,4- (CH3)2C6H4BiCl3)2]In the crystal structures of the three solid state complexes (C6H4(CH3)2BiCl3 (C6H4(CH3)2 = o-xylene: 1, m-xylene: 2, p-xylene: 3) quasi-dimeric units of almost undistorted, arene coordinated BiCl3 fragments can be found that are further associated via additional Bi—Cl contacts to form one-dimensional polymeric chains. Whereas the chains of 2 and 3 are constituted by Bi2Cl2 four-membered rings only, further Cl-bridging in 1 leads to additional trigonal-bipyramidal arrangements with Bi atoms exhibiting coordination numbers of 3 + 3 + 1 and 3 + 2 + 1, respectively (prim. + sec. Cl contacts + arene). The arene-metal bonding is characterized by Bi-arene distances in the range from 297 - 306 pm, including ring slippages of 24 -41 pm and 73 pm with the Bi atoms being six and seven coordinated, respectively. The direction of this slipping with respect to the arene's methylation sites cannot be understood in terms of electronic influences but is shown to be caused by steric demands. The values IP1 of the arenes prove to determine the colours of the complexes.
    Notes: In den Festkörperstrukturen der drei Komplexe (C6H4(CH3)2)BiCl3 (C6H4(CH3)2 = o-Xylol: 1, m-Xylol: 2, p-Xylol: 3) findet man quasidimere Einheiten fast unverzerrter, arenkoordinierter BiCl3-Fragmente, die über zusätzliche Bi—Cl-Kontakte zu eindimensionalen polymeren Ketten assoziiert sind. Während die Ketten von 2 und 3 nur aus Bi2Cl2-Vierringsegmenten bestehen, führt eine weitere Verbrückung in 1 zusätzlich zu trigonal-bipyramidalen Anordnungen mit Bi-Atomen der Koordinationszahlen 3 + 3 + 1 bzw. 3 + 2 + 1 (prim. + sek. Cl-Kontakte + Aren). Die Bindung des Arens an das Metall ist durch Bi-Aren-Abstände zwischen 297 und 306 pm charakterisiert. Die „ring slippage“ beträgt 24-41 bzw. 73 pm bei den sechsfach bzw. siebenfach koordinierten Bi-Atomen. Die Richtung dieser Verschiebung in bezug auf die Lage der Methylgruppen des Arens kann nicht auf elektronischer Basis interpretiert werden, sondern ist sterisch verursacht. Für die Farbe der Komplexe erweist sich IP1 des Arens als bestimmend.
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  • 93
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1147-1153 
    ISSN: 0044-2313
    Keywords: O,O′,O″,O‴-tetraphenyl μ-imido-dithiodiphosphate ; N-(O,O′-diphenylthiophosphoryl)-O″,O‴-diphenylthiophosphorimidate ; Bis(O,O′,O″,O‴-tetraphenyl μ-imido-dithiodiphosphato) palladium chelate ; Bis[N-O,O′-diphenylthiophosphoryl-O″,O‴-diphenylthiophosphorimidato] palladium chelate ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Der Tetraphenylester der μ-Imido-dithiodiphosphorsäure und sein Palladiumkomplex  -  KristallstrukturenDie Darstellung der Verbindung [(C6H5O2PS]2NH (SS) und ihres Palladiumkomplexes [Pd{C6H5O)2P(S)NP(S)(OC6H5) 2}2] (PDSS) wird beschrieben. Die Verbindungen werden elementaranalytisch, durch NMR- und Massenspektrometrie sowie mittels Röntgen-Kristallstrukturanalyse charakterisiert. Die Struktur von SS enthält zwei unabhängige Moleküle in einer asymmetrischen Einheit, die über N … H … S Wasserstoffbrücken zu Dimeren verbunden sind. SS ist eine Br⊘nsted-Säure, die mit PdII zu einem neutralen Chelatkomplex reagiert. Die Struktur von PDSS besteht aus isolierten Molekülen mit dem Pd-Atom als Symmetriezentrum. Das Pd ist an 4 S-Atome in einer verzerrt quadratisch-planaren Anordnung mit einem mittleren Abstand Pd—S von 2,345(6) Å und Winkel S—Pd—S von 98,29(4)° gebunden.
    Notes: The preparations of [(C6H5O)2PS]2NH (SS) and its Pd complex [Pd{C6H5O2P(S)NP(S)(OC6H5) 2}2] (PDSS) are described. The compounds were characterized by elemental analysis, NMR, and mass spectra and X-ray structure analysis. The structure of SS contains two independent molecules in an asymmetric unit which are joined into dimers via N … H … S hydrogen bonds. SS is a Br⊘nsted acid And reacts with PdII to a neutral chelate complex. The structure of PDSS is composed of isolated molecules with Pd atom in the center of symmetry. The Pd atom is coordinated by 4 S atoms in a distorted square-planar arrangement with average distance Pd—S 2.345(6) Å and an angle S—Pd—S 98.29(4)°.
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  • 94
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1132-1136 
    ISSN: 0044-2313
    Keywords: Hexamolybdotellurate(VI) ; crystal structure ; hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über das Protonenakzeptorverhalten von [TeMo6O24]6- in Na4(NH4)2[TeMo6O24] · 16H2OFarblose Einkristalle von Na4(NH4)2[TeMo6O24] · 16H2O wurden in wäßriger Lösung gezüchtet (Raumgruppe P1, a = 1 075,3(1), b = 1 074,2(1), c = 1 089,8(1) pm, = 96,259(9), β = 118,556(7), γ = 113,355(8)°, Z = 1, 295 K, 311 Parameter, 3 689 Reflexe, Rg = 0,0197). Es liegen zwei kristallographisch unabhängige Na+ Kationen vor. Na(1) ist oktaedrisch von vier Wassermolekülen und zwei Sauerstoffatomen des zentrosymmetrischen [TeMo6O24]6--Anions umgeben. Na(2) ist in stark verzerrt trigonal-bipyramidaler Weise von fünf Wassermolekülen koordiniert. Je zwei dieser Na(H2O)5+-Bipyramiden sind mit zwei NH4+-Kationen über Wasserstoffbrückenbindungen zu zentrosymmetrischen kationischen Clustern verknüpft. Mit Ausnahme von O(10) wirken alle Sauerstoffatome des [TeMo6O24]6--Anions ungeachtet ihrer unterschiedlichen Bindigkeit bezüglich Mo bzw. Te als annähernd gleichwertige Protonenakzeptoren in Wasserstoffbrückenbindungen zu den NH4+-Kationen und den Kristallwassermolekülen.
    Notes: Colourless triclinic single crystals of Na4(NH4)2[TeMo6O24] · 16H2O were grown in aqueous solution (space group P1, a = 1 075.3(1), b = 1 074.2(1), c = 1 089.8(1) pm, = 96.259(9), β = 118.556(7), γ = 113.355(8)°, Z = 1, 295 K, 311 parameters, 3 689 reflections, Rg = 0.0197). There are two crystallographically independent Na+ cations. Na(1) is coordinated octahedrally by four water molecules and two oxygen atoms of the centrosymmetric [TeMo6O24]6- anion. Na(2) is bound to five water molecules in a considerably distorted trigonally bipyramidal fashion. These bipyramids are linked with NH4+ by hydrogen bonds to yield centrosymmetric cluster cations consisting of two NH4+ and two Na(H2O)5+ each. Hydrogen bonds envolving all except one (O(10)) of the oxygen atoms of the [TeMo6O24]6- anion as almost equivalent proton acceptors regardless of their bonding mode to Te and Mo, respectively, establish further connections to NH4+ and the water of crystallization.
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  • 95
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1137-1146 
    ISSN: 0044-2313
    Keywords: Molybdotellurate(VI) ; crystal structure ; differential thermal analysis ; hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Wasserreiche Molybdotellurate: Darstellung und Kristallstruktur von Li6[TeMo6O24] · 18 H2O und Li6[TeMo6O24] · Te(OH)6 · 18 H2OLi6[TeMo6O24] · 18 H2O kristallisiert in der triklinen Raumgruppe P1 (a = 1 041,7(1), b = 1 058,6(1), c = 1 070,8(1) pm, α = 61,08(1), β = 60,44(1), γ = 73,95(1)°. Die Einkristallröntgenstrukturanalyse (Z = 1, 295 K, 317 Parameter, 3 973 Reflexe, Rg = 0,0250) zeigte, daß eine verzweigte, unendliche Kette aus kantenverknüpften Li-Koordinationspolyedern das markante Strukturmerkmal dieser Verbindung ist. Eines der vier kristallographisch unabhängigen Li+-Kationen ist oktaedrisch koordiniert. Bei den übrigen Li+-Kationen liegt verzerrt trigonal-bipyramidale Koordination vor. Lediglich drei kristallographisch unabhängige Sauerstoffatome (O(9), O(10), O(12)) des zentrosymmetrischen [TeMo6O24]6--Anions sind an Li+ koordiniert. Die übrigen Positionen in den Li+-Koordinationssphären sind durch Wassermoleküle besetzt. Die Sauerstoffatome des [TeMo6O24]6--Anions treten in intermolekularen Wasserstoffbrückenbindungen ungeachtet ihrer unterschiedlichen Bindigkeit bezüglich Mo und Te als annähernd gleichwertige Protonenakzeptoren auf.Li6[TeMo6O24] · Te(OH)6 · 18 H2O kristallisiert in der monoklinen Raumgruppe P21/n mit Z = 4, a = 994,1(3), b = 2 344,8(10), c = 1 764,9(4) pm und β = 91,36(4)°. Die Einkristallröntgenstrukturbestimmung mit 627 Parametern und 5900 Reflexen (295 K) konvergierte bei Rg = 0,0324. Es liegen sechs kristallographisch unabhängige Li+-Kationen vor. Die Koordinationspolyeder von Li(1), Li(2), Li(3) und Li(4) sind über gemeinsame Kanten zu einem achtgliedrigen, zentrosymmetrischen Strang verknüpft. Die Koordinationspolyeder von Li(5) und Li(6) sind über eine gemeinsame Ecke zu Zweiergruppen verbunden. Sämtliche Sauerstoffatome des eingeschlossenen Te(OH)6-Moleküls, aber nur drei Sauerstoffatome (0(13), 0(18), O(23)) des [TeMo6024]6--Anions, welches hier über keine kristallographische Symmetrie verfügt, sind an Li+ koordiniert. Die Sauerstoffatome des Anions treten in Wasserstoffbrückenbindungen von überwiegend mittlerer Stärke als Protonenakzeptoren auf. Kurze intermolekulare Wasserstoffbrückenbindungen verbinden die [TeMo6O24]6--Anionen mit den Te(OH)6-Molekülen zu unendlichen Ketten.
    Notes: Li6[TeMo6O24] · 18 H2O is triclinic (space group P1, a = 1 041.7(1), b = 1 058.6(1), c = 1 070.8(1) pm, α = 61.08(1), β = 60.44(1), γ = 73.95(1)°). Single crystal X-ray structure analysis (Z = 1, 295 K, 317 parameters, 3 973 reflections, Rg = 0.0250) revealed an infinite branched chain of edge-sharing Li coordination polyhedra to be the prominent structural feature. One of the four crystallographically independent Li+ is coordinated octahedrally. The coordination polyhedra of the remaining Li+ are distorted trigonal bipyramids. Only three unique oxygen atoms (O(9), O(10), O(12)) of the centrosymmetric [TeMo6O24]6- anion are bound to Li+. The further positions in the coordination spheres of the Li+ are occupied by water molecules. Intermolecular hydrogen bonds involve mainly oxygen atoms of the [TeMo6O24]6- anion as nearly equivalent proton acceptors without regard to their different bonding modes to Te and Mo, respectively.Li6[TeMo6O24] · Te(OH)6 · 18 H2O crystallizes monoclinically in space group P21/n with Z = 4, a = 994.1(3), b = 2 344.8(10), c = 1 764.9(4) pm, and β = 91.36(4)°. Single crystal structure analysis with least squares refinement of 627 parameters (5 900 reflections, 295 K) converged to Rg = 0.0324. There are six unique Li+ cations. The coordination polyhedra of Li(1), Li(2), Li(3), and Li(4) are linked by common edges to yield an eight membered centrosymmetric strand. The coordination polyhedra of the remaining two Li+ sites (Li(5), Li(6)) are connected to a dimeric unit via a common corner. All oxygen atoms of the Te(OH)6 molecule are involved in the coordination of Li+. However, only three oxygen atoms (O(13), O(18), O(23)) of the [TeMo6O24]6- anion which lacks crystallographic symmetry are involved in the coordination of Li+. The oxygen atoms of the anion act as proton acceptors in hydrogen bonds of predominantly medium strength. Te(OH)6 molecules and [TeMo6O24]6- anions connected by strong hydrogen bonds form an infinite chain.
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  • 96
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1155-1160 
    ISSN: 0044-2313
    Keywords: Tin tetrathalliumtritelluride ; lead tetrathalliumtritelluride ; preparation ; crystal structure ; Cr5B3 type ; In5Bi3 type ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of SnTl4Te3 and PbTl4Te3.We describe the synthesis and crystal structure of two ternary derivatives MTl4Te3 of the parent phase Tl5Te3. Both the derivatives, SnTl4Te3 and PbTl4Te3, crystallize with the In5Bi3 type of structure: space group I4/mcm, Z = 4. The cell constants of SnTl4Te3(PbTl4Te3) are as follows: a = 8.819(2) Å (8.841(2)Å), c = 13.013(3) Å (13.056(3) Å), c/a = 1.47 (1.48). Short M—Te distances of 3.25 Å (3.26 Å) are obtained in ∞1[MTe2/2] chains, which run along [001]. The M atoms are further surrounded by additional tellurium atoms in such a way that octahedra occur, which share common vertices to build up a three dimensional infinite network ∞3[MTe6/2]. The remaining thallium atoms span cubes around the octahedra: ∞3[MTe6/2]Tl8/2 = MTl4Te3.An alternative structure description takes into account bent fragments Tl2Te with Tl—Te distances of 3.15 Å (3.17 Å) as the constitutional elements of M-centered, slightly distorted rhombic dodecahedra as the only polyhedra of the structure. Along [001] they share common vertices, whereas in the tetragonal a-a-plane they are interconnected via common faces.
    Notes: Die Darstellung und die Kristallstruktur der zwei ternären Abkömmlinge SnTl4Te3 und PbTl4Te3 werden beschrieben. Beide kristallisieren isotyp zu ihrer Mutterphase Tl5Te3 im In5Bi3-Typ, der seinerseits eine isopuntale Unterfamilie des Cr5B3-Typs bildet. Die Raumgruppe ist I4/mcm, die Zahl der Formeleinheiten beträgt 4. Die Gitterkonstanten für SnTl4Te3(PbTl4Te3) lauten a = 8,819(2) Å (8,841(2) Å), c = 13,013(3) Å (13,056(3) Å), das c/a-Verhältnis beträgt 1,47 (1,48).In zwei Fragmenten des dreidimensionalen Verbandes treten kurze M—Te—Abstände auf (M = Sn, Pb, Tl). Je nachdem, welchem Fragment man mehr Aufmerksamkeit schenkt, sind zwei alternative, aber gleichwertige Strukturbeschreibungen möglich: Die erstere lehnt sich an die bei der Mutterphase Tl5Te3 gewählte an und betont die kurzen Sn—Te— bzw. Pb—Te—Abstände in den parallel zur [001]-Richtung verlaufenden linearen Ketten ∞1[MTe2/2](Sn—Te: 3,25 Å, Pb—Te: 3,26 Å). Die M-Atome der Ketten werden durch weitere Tellur-Atome zu einem allseits spitzenverknüpften Oktaederverband ∞1[MTe6/2] komplettiert. Die Oktaeder werden würfelförmig von den Thallium-Atomen umgeben: ∞3[MTe6/2]Tl8/2 = MTl4Te3.De zweite betont die gewinkelten Fragmente Tl2Te(Tl—Te in SnTl4Te3: 3,15 Å, Tl—Te in PbTl4Te3: 3,16 Å). Die Tl2Te-Fragmente sind Teile verzerrter Tl2Te2-Rhomben. Diese Rhomben bauen M-zentrierte Rhombendodekaeder auf (M = Sn, Pb), die das einzige zum Strukturaufbau nötige Polyeder sind.
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  • 97
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1177-1182 
    ISSN: 0044-2313
    Keywords: 3, 5-Dimethyl-4-oxo-4-phenoxy-1 λ4-thia-2, 3,-5, 6-tetraaza-4λ5-phosphacyclohexane-2, 6-dicarbonic acid diethylester ; 3, 5-Dimethyl-4-phenoxy-4-thioxo-1λ4-thia-2, 3, 5, 6-tetraaza-4λ5-phosphacyclohexane-2, 6-dicarbonic acid diethylester ; crystal structure ; NMR spectra ; twist-boat conformation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphorus(V)-Hydrazine-Sulfur(IV) Heterocycles with Twist-Boat Conformation.Unlike the corresponding unsubstituted compounds N-ethoxycarbonyl-substituted dihydrazidophosphoric acid derivatives do not react with thionylchloride under redoxdecomposition but yield sulfur containing sixmembered rings. In solution (NMR spectra) as well as in the crystal (X-ray structure analysis) the rings adopt unusual twist-boat conformations. Due to the rather bulky substituents high energies of interconversion between enantiomeric twist-forms are found: 75 ± 2 kJ/mol.
    Notes: N-ethoxycarbonyl-substituierte Dihydrazidoderivate der Phosphorsäure reagieren mit Thionylchlorid nicht wie die entsprechenden unsubstituierten Verbindungen unter Redoxzersetzung sondern unter Bildung schwefelhaltiger Sechsringe. Die Ringe liegen sowohl in Lösung (NMR-Spektren) als auch im Kristall (Röntgenstrukturanalyse) in einer ungewöhnlichen Twist-Boot-Konformation vor. Bedingt durch die sperrigen Substituenten ergeben sich hohe Aktivierungsenergien für die Interkonversion der enantiomeren Twistkonformationen von 75 ± 2 kJ/mol.
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  • 98
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    Zeitschrift für anorganische Chemie 619 (1993), S. 1203-1208 
    ISSN: 0044-2313
    Keywords: β-Sodium thiocarbonate ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Modified Synthesis and Crystal Structure Determination of β-Na2CS3.β-Na2CS3 has been synthesized via a novel route from Na2S and CS2, and its crystal structure has been determined using single crystal techniques (for crystallographic informations see “Inhaltsübersicht”). Structural relations between Li2CO3 and β-Na2CS3 are discussed. The ionic conductivities are 3 · 10-11S cm-1 and 1.3 · 10-2S cm-1 at 50°C and 250°C, respectively.
    Notes: In der Literatur als β-Na2CS3 beschriebenes Natriumthiocarbonat wurde auf einem neuen Wege aus Na2S und CS2 dargestellt und die Kristallstruktur aufgeklärt (C2/c; a = 1 003,6(1) pm, b = 633,7(1) pm, c = 855,5(1) pm, β = 108,05(1)°, Z = 4,1582 unabhängige Reflexe, R = 0,034). Strukturbeziehungen zu Li2CO3 werden diskutiert. Die Ionenleitfähigkeiten betragen 3 · 10-11S cm-1 und 1,3 · 10-2S cm-1 bei 50°C bzw. 250°C.
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  • 99
    ISSN: 0044-2313
    Keywords: Complex compounds ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Crystal Structures and Spectroscopic Investigations of 3d-Transition Metal Complexes with Bicyclo[2.2.1]hept-5-ene-2-endo,3-cis-dicarboxylic Acid and N,N-Donor LigandsThe synthesis of coordination compounds of the general type [MLdam(H2O)3] · 2.5 H2O with M = Mn2+, Co2+, Ni2+; H2L = bicyclo[2.2.1]hept-5-ene-2-endo,3-cis-dicarboxylic acid and dam = 2,2′-dipyridyl, 1,10-phenanthroline has been described. The complexes have been characterized by elementary analysis, infrared and electronic spectra and magnetic susceptibility measurements.The results of X-ray crystal structure analyses of [MnLdipy(H2O)3] · 2.5 H2O (1 a) and [CoLdipy(H2O)3] · 2,5 H2O (1 b) show, that both compounds crystallize isotypically and prove the octahedral coordination of the metal atoms. The dicarboxylate anion is coordinated to the central atom by an O atom of only one carboxylate group, the other one is in the ionic state. One O atom of each carboxylate group makes an intramolecular hydrogen bond with a water molecule of the coordination sphere. The other crystal water molecules form a network of H bonds one with another and with the complex molecules, thus stabilizing the crystal packing.
    Notes: Die Synthese von Koordinationsverbindungen der allgemeinen Zusammensetzung [MLdam(H2O)3] · 2,5 H2O mit M = Mn2+, Co2+, Ni2+; H2L = Bicyclo[2.2.1]hept-5-en-2-endo,3-cis-dicarbonsäure und dam = 2,2′-Dipyridyl, 1,10-Phenanthrolin wird beschrieben. Die Komplexe werden durch quantitative Analysen, IR- und Elektronenspektren sowie Magnetmessungen charakterisiert.Die Ergebnisse der Röntgenkristallstrukturanalyse von [MnLdipy(H2O)3] · 2,5 H2O (1 a) und [CoLdipy(H2O)3] · 2,5 H2O (1 b) zeigen, daß beide Verbindungen isotyp kristallisieren und belegen die oktaedrische Koordination der Metallatome. Das Dicarboxylat-Anion ist mit nur einem O-Atom am Zentralatom gebunden, die zweite Carboxylatgruppe liegt ionisch vor. Je ein O-Atom jeder Carboxylatgruppe geht eine intramolekulare Wasserstoffbrückenbindung mit einem koordinativ gebundenem Wassermolekül ein. Die restlichen Kristallwassermoleküle bilden ein die Packung stabilisierendes Wasserstoffbrückennetz untereinander und mit den Komplexmolekülen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 100
    ISSN: 0044-2313
    Keywords: Lanthanum niobium selenides ; misfit layer compound ; crystal structure ; electronic properties ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Struktur und elektronische Transporteigenschaften der „Misfit“-Schichtverbindung (LaSe)1,14(NbSe2)2, „LaNb2Se5“.Die neue „Misfit“-Schichtverbindung (LaSe)1,14(NbSe2)2 wurde aus den Elementen bei 1050°C dargestellt und ihre Struktur in mehreren Teilschritten bestimmt. Die Struktur besteht aus einer alternierenden Stapelfolge von [LaSe]- und zwei [NbSe2]-Schichten in c-Richtung. Der „Misfit“ zwischen den zwei verschiedenen Schichten wird entlang der a-Richtung deutlich: a1(LaSe)=6,0191 Å und a2(NbSe2)=3,4372 Å, woraus sich ein Verhältnis von 1,751 ergibt, das 7/4 sehr nahe kommt. Der elektrische Widerstand wurde in Abhängigkeit von der Temperatur gemessen. Die Kristalle zeigen supraleitende Eigenschaften ab 5,3 K.
    Notes: The new misfit layer compound (LaSe)1.14(NbSe2)2 has been synthesized from the elements at 1050- and its structure has been determined by a composite approach. The structure has an alternating stacking sequence of [LaSe] and two [NbSe2] layers along the c direction. The misfit of the two different layers is occurring along the a direction: a1(LaSe)=6.0191 Å and a2(NbSe2)=3.4372 Å therefore yielding a ratio of 1.751 which is very close to 7/4. An investigation of electrical resistivity was done. The crystal shows superconducting properties at 5.3 K.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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