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  • 1995-1999  (53)
  • 1975-1979  (22)
  • 1900-1904  (50)
  • Inorganic Chemistry  (113)
  • Cell & Developmental Biology  (12)
  • 1
    Electronic Resource
    Electronic Resource
    [Gd4(C2)](Cl, I)6, an Interstitially Stabilized Heteroleptic Gadolinium SesquihalideDedicated to Professor John D. Corbett on the Occasion of his 70th Birthday (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 494-500 
    Details
    ISSN: 0044-2313
    Keywords: Gadolinium sesquihalide ; interstitial carbon units ; crystal structure ; electronic structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [Gd4(C2)](Cl, I)6, ein interstitiell stabilisiertes, heteroleptisches Gadoliniumsesquihalogenid[Gd4(C2)](Cl, I)6 erhält man aus CsI, Gd, GdCl3 und C2I4 in verschweißten Niob-Ampullen bei 1000/800°C in Form von schwarzen, glänzenden Nadeln. Die Kristallstruktur (tetragonal; P4/mbm; Z = 2; a = 1347,5(1); c = 1212,5(1) pm) ist ähnlich wie jene von Na[Mo4]O6 bzw. [Sc4B]Cl6. Trans-kantenverknüpfte [Gd6]-Oktaeder verlaufen parallel [001]. Sie enthalten interstitielle C2-Einheiten, Jedes dritte Oktaeder enthält fehlgeordnete C2-Einheiten, senkrecht zu jenen in den benachbarten [Gd6(C2)]-Oktaedern. Diese sind daher entlang der (pseudo)-C4-Achse gestaucht. Rechnungen zur elektronischen Struktur zeigen, daß insgesamt 13 Elektronen zur Auffüllung aller Metall-Metall-bindenden Zustände für eine „leere“ [Gd4]Cl6-Struktur nötig wären. Die Einlagerung der C2-Dimeren verändert die Bindungsverhältnisse in [Gd4(C2)]X6 (X = Cl, I) erheblich. Die formale Ladung von -6 der C2-Einheit wird durch das Aufsplitten der πg-Zustände reduziert, Gd—Gd und Gd—C-bindende Zustände werden besetzt und bindende dx2-y2-Orbitale kombinieren zu den am niedrigsten liegenden nicht besetzten Zuständen.
    Notes: [Gd4(C2)](Cl, I)6 is obtained from CsI, Gd, GdCl3 and C2I4 in sealed niobium containers at 1000/800°C as black, shiny needles. The crystal structure (tetragonal, P4/mbm, Z = 2, a = 1347.5(1), c = 1212.5(1) pm) is similar to that of Na[Mo4]O6 and [Sc4B]Cl6. It may be regarded as being built from octahedra sharing common trans edges running in the [001] direction. The octahedra contain C2 units as interstitials. Every third octahedron contains a disordered C2 unit perpendicular to those in the two neighboring [Gd6(C2)] octahedra and is therefore compressed in the direction of the (pseudo) C4 axis. Calculations of the electronic structure of an “empty” [Gd4]Cl6 structure reveals a total of 13 electrons necessary to occupy all metal-metal bonding states. The incorporation of a carbon dimer substantially alters the bonding conditions for [Gd4(C2)]X6 (X = Cl, I). The formal charge of -6 of the C2 unit is significantly reduced as πg states split up, Gd—Gd and Gd—C bonding states are occupied and bonding dx2—y2 orbitals combine to form the lowest unoccupied energy states.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220318
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  • 2
    Electronic Resource
    Electronic Resource
    Di- und Polyaminozucker, XXI. Synthese von Derivaten der 2,4-Diamino-2,3,4-tridesoxy-D-ribo-hexose (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3397-3411 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Di-and Polyamino Sugars, XXI. Synthesis of Derivatives of 2,4-Diamino-2,3,4-trideoxy-D-ribo-hexoseStarting with D-glucose the title compound has been synthesized as its di-N-acetyl. -trifluoroacetyl and N,N′-bis(2,4-dinitrophenyl) derivative. The free sugar could not be obtained in a pure state.
    Notes: Die Titelverbindung wurde, ausgehend von D-Glucose, in Form ihres Di-N-acetyl-, -trifluoracetyl- und ihres N,N′-Bis(2,4-dinitrophenyl)-Derivates erhalten. Reindarstellung des freien Zuckers gelang nicht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081031
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  • 3
    Electronic Resource
    Electronic Resource
    Heterocyclische Siebenring-Verbindungen, XVI. Synthese gezielt 3,5-substituierter 4-Phenyl-1-benzothiepine (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3596-3610 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic Seven-membered Ring Compounds, XVI. Synthesis of 3,5-Substituted 4-Phenyl-1-benzothiepins4-Phenyl-1-benzothiepins 7 and 8 are synthesized starting from their 5-methoxy-2,3-dihydro-precursor 2; using the 2,5-dihydro-intermediate 12 yields the 4-phenyl-1-benzothiepins 13 and 14. The 1-benzothiepin 17 can be obtained from the diketone 1 directly. The 3-cyano-substituted compound 22 is prepared from its 2,5-dihydro-precursor 21. Some ring-contraction and ring-cleavage reactions of the heterocyclic seven-membered ring-system are described.
    Notes: Die 5-Methoxy-2,3-dihydro-Vorstufe 2 wird in die 4-Phenyl-1-benzothiepine 7 und 8 übergeführt; aus der 2,5-Dihydro-Vorstufe 12 werden die 4-Phenyl-1-benzothiepine 13 und 14 dargestellt. Das 1-Benzothiepin 17 wird direkt aus dem Siebenring-Diketon 1 erhalten. Das 3-cyan-substituierte 1-Benzothiepin 22 erhält man aus der 2,5-Dihydro-Vorstufe 21. Es werden einige Ringverengungsbzw. Ringspaltungsreaktionen des heterocyclischen Siebenring-Systems beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081121
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  • 4
    Electronic Resource
    Electronic Resource
    Eine moderne Strömungsapparatur für kinetische Messungen an thermischen Umlagerungen in der Gasphase: Thermolysekinetik neuer Kleinringverbindungen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2545-2560 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Modern Flow Reactor for Kinetic Measurements of Gasphase Thermal Rearrangements: Thermolysis Kinetics of Some New Small Ring CompoundsAn apparatus with a laminar flow reactor is introduced, which serves for kinetic measurements in the gas phase using rather small amounts (5-10mg) of compounds. Test runs for the well studied vinylcyclopropane rearrangement and the retro-Diels-Alder reaction of dicyclopentadiene demonstrate the reliability of the results thus obtained.  -  The thermolytic rearrangements of the following compounds were studied with this device: diademane (1), dispiro[2.0.2.4]deca-7,9-diene (3) including the formation of o-ethylstyrene (4) and tetrahydronaphthalene 5, 3,3,4,4-tetramethyl-1,5-hexadiene (6), 1,4-bis(cyclopropylidene)butane (8), dispiro[cyclopropane-1,2′-bicyclo[2.2.0]hexane-3′,1″-cyclopropane] (10), 2,2,3,3-tetramethylbicyclo[2.2.0]hexane (11) and 2,2-dimethylbicyclo[2.2.0]hexane-3-spirocyclopropane (12). All these reactions followed first order rate laws with the following Arrhenius relationships: ln(k1) = 33.6 - 31600/RT, ln(k3) = 34.2 - 35500/RT, ln(k4) = 33.6 - 35100/RT, ln(k5) = 33.6 - 36000/RT, ln(k6) = 29.1 - 33300/RT, ln(k8) = 22.0 - 26200/RT, ln(k10) = 32.0 - 35200/RT, ln(k11) = 32.0 - 40900/RT, ln(k12) = 32.3 - 39400/RT. The kinetic isotope effects of 1.4 and 1.1 (at 175°C) for the formation of 4 and 5 respectively and the difference Ea4 - Ea5 ≈ 0.1-0.9 kcal/mol strongly favor a mechanism, by which 3 rearranges via a 1,6-diradical to yield 4 and 5 by intramolecular disproportionation and recombination, respectively.
    Notes: Für kinetische Messungen in der Gasphase wird eine Apparatur mit laminarem Strömungsreaktor vorgestellt, die mit sehr geringen Substanzmengen (5-10mg) auskommt. Testmessungen an der eingehend untersuchten Vinylcyclopropanumlagerung und der Retro-Diels-Alder-Reaktion des Dicyclopentadiens beweisen die Verläßlichkeit der gewonnenen Daten.  -  Mit der Apparatur wurden die Thermolysen von Diademan (1), Dispiro[2.0.2.4]deca-7,9-dien (3) einschließlich Bildung von o-Ethylstyrol (4) und Tetrahydronaphthalin (5), 3,3,4,4-Tetramethyl-1,5-hexadien (6), 1,4-Bis(cyclopropyliden)butan (8), Dispiro[cyclopropan-1,2′-bicyclo[2.2.0]hexan-3′,1″-cyclopropan] (10), 2,2,3,3-Tetramethylbicyclo[2.2.0]hexan (11) und 2,2-Dimethylbicyclo[2.2.0]-hexan-3-spirocyclopropan (12) untersucht. Alle Reaktionen verlaufen nach Zeitgesetzen erster Ordnung und ergeben die folgenden Arrhenius-Beziehungen: ln(k1) = 33.6 - 31600/RT, ln(k3) = 34.2 - 35500/RT, ln(k4) = 33.6 - 35100/RT, ln(k5) = 33.6 - 3600/RT, ln(k6) = 29.1 - 33300/RT, ln(k8) = 22.0 - 26200/RT, ln(k10) = 32.0 - 35200/RT, ln(k11) = 32.0 - 40900/RT, ln(k12) = 32.3 - 39400/RT. Die kinetischen Isotopieeffekte von 1.4 und 1.1 bei der Bildung von 4 bzw. 5 (gemessen bei 175°C) und die gefundene Differenz Ea4 - Ea5 ≈ 0.1-0.9 kcal/mol sprechen für einen Umlagerungsmechanismus von 3 über ein 1,6-Diradikal, das intramolekular disproportioniert und rekombiniert zu 4, bzw. 5.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100713
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  • 5
    Electronic Resource
    Electronic Resource
    Phosphorhaltige Kohlenhydrate, XVII: Untersuchung der Hydrierung ungesättigter Glycosylphosphonate. Anomerer Effekt und A-Wert der Dimethylphosphono-Gruppe (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 3325-3335 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphorus-containing Carbohydrates, XVII: Studies on the Hydrogenation of Unsaturated Glycosylphosphonates. Anomeric Effect and A-Value of the Dimethylphosphono GroupBy hydrogenation unsaturated glycosylphosphonates of type 1 give rise to the formation of 2,3-dideoxyglycosylphosphonates 2 and 2,3,4-trideoxyglycosylphosphonates 3. Their product ratio depends on configuration and conformation of the educts 1a-f. 1H and 13H and 13C NMR data permit an assigment of the anomers of the hydrogenated glycosylphosphonates. For the one-bond coupling constant between 13C-1 and 31P the correlation 1JC, Peq 〉 1JC, Pax is valid, which exhibits a difference of 19-23 Hz. The unsaturated glycosylphosphonates show deviations from Hudson's isorotation rule. In dimethyl cis-4-methyl-1-cyclohexanephosphonate (9) the A-value of the dimethylphosphono group has been determined to 8.34 kJ/mol. The ratio of conformers in 3a leads to an anomeric effect of the dimethylphosphono group of 2.33 kJ/mol.
    Notes: Ungesättigte Glycosylphosphonate vom Typ 1 liefern bei der Hydrierung außer 2,3-Didesoxyglycosylphosphonaten 2 auch 2,3,4-Tridesoxyglycosylphosphonate 3. Das Produktverhältnis ist von Konfiguration und Konformation der Ausgangsprodukte 1a-f abhängig. 1H- und 13C-NMR-Daten erlauben eine Anomerenzuordnung der hydrierten Glycosylphosphonate. Für die 13C-31P-Direktkopplung an C-1 gilt 1JC, Peq 〉 1JC, Pax mit einer Differenz von 19-23 Hz. Die ungesättigten Glycosylphosphonate zeigen Abweichungen von der Hudsonschen Regel. Am Dimethyl-cis-4-methyl-1-cyclohexanphosphonat (9) wurde der A-Wert der Dimethylphosphono-Gruppe zu 8.34 kJ/mol bestimmt. Aus der Konformerenverteilung bei 3a ergibt sich der anomere Effekt der Dimethylphosphono-Gruppe zu 2.33 kJ/mol.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781111006
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  • 6
    Electronic Resource
    Electronic Resource
    Darstellung, chemische Eigenschaften und thermische Umlagerung von Spiro[3.4]octa-5,7-dien (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2561-2573 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Chemical Properties and Thermal Rearrangement of Spiro[3,4]octa-5,7-dieneThe synthesis of spiro[3.4]octa-5,7-diene (2) was achieved along two routes starting from spiro-[3.4]octan-5-one (5). In both cases the last step was a dehydrohalogenation of the halospiro-[3.4]octenes 8b/9b and 11, respectively, which had to be carried out at room temperature, because 2 dimerizes about as fast as cyclopentadiene. It also underwent addition of maleic anhydride and 2-chloroacryloyl chloride to yield 13 and 14a respectively. 14a could be degraded to the bicyclo[2.2.1]hept-2-en-5-on-7-spirocyclobutane (15a), which served as a precursor to the hydrocarbon 17. Above 90°C 2 isomerizes to a mixture of bicyclo[3.3.0]octadienes 18a and 18b. This reaction followed a first order kinetics in the gas phase with the Arrhenius equation ln(k) = 31.7 - 29200/RT. These kinetic parameters are interpreted in terms of a sigmatropic [1,5]-alkyl shift.
    Notes: Die Synthese von Spiro[3.4]octa-5,7-dien (2) gelingt ausgehend von Spiro[3.4]octan-5-on (5) auf zwei Wegen. Bei beiden wird in der letzten Stufe eine Dehydrohalogenierung eines Halogenspiro[3.4]octens 8b/9b bzw. 11 bei Raumtemperatur vorgenommen, weil 2 bei höheren Temperaturen ähnlich schnell dimerisiert wie 1,3-Cyclopentadien. Ebenso addiert es leicht Maleinsäureanhydrid und 2-Chloracryloylchlorid zu 13 bzw. 14a. 14a läßt sich zum Bicyclo[2.2.1]hept-2-en-5-on-7-spirocyclobutan (15a) abbauen, aus dem der Kohlenwasserstoff 17 zugänglich ist. Oberhalb von 90°C isomerisiert 2 zu einem Gemisch der Bicyclo[3.3.0]octadiene 18a und 18b. Die Kinetik dieser Reaktion in der Gasphase zeigt einen Verlauf erster Ordnung und folgt dem Arrhenius-Ansatz ln(k) = 31.7 - 29200/RT. Daraus ist für den Mechanismus auf eine konzertierte [1,5]-Alkylverschiebung zu schließen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100714
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  • 7
    Electronic Resource
    Electronic Resource
    Optisch aktive, aromatische Spirane, 5. Stereochemie von Metallocenen, 39. Eine universelle Methode zur Darstellung, Konfigurationsermittlung und Bestimmung der enantiomeren Reinheit chiraler 2,2′-Spirobiindane (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1403-1420 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Optically Active, Aromatic Spiranes, 5. Stereochemistry of Metallocenes, 39. An Universal Method for the Preparation, and Determination of the Absolute Configuration and Enantiomeric Purity of Chiral 2,2′-SpirobiindanesFrom optically active tricarbonyl(1-oxoindane)chromium complexes 1 of known configuration and enantiomeric purity by reaction with phthalaldehydic esters 2 and hydrogenation of the benzal derivatives 4 chiral key compounds 5 and 6 for the preparation of 2,2′-spirobiindan-1,1′-diones are obtained. Cyclization of 6 yields diastereomers (cis- and trans-7) which after mild removal of Cr(CO)3 afford the enantiomeric biindanones 8 from which 2,2′-spirobiindanes 9 are accessible. Chiralities and enantiomeric purities of all spiranes can easily be deduced from those of the indanones 1. This universal principle is presented for several methyl- and methoxy-2,2′-spirobiindan-1,1′-diones and -biindanes.
    Notes: Aus optisch aktiven Tricarbonyl(1-oxoindan)chrom-Komplexen 1 bekannter Konfiguration und enantiomerer Reinheit werden durch Umsetzung mit Phthalaldehydsäureestern 2 und Hydrierung der Benzalderivate 4 chirale Schlüsselverbindungen 5 bzw. 6 zur Darstellung von 2,2′-Spirobiindan-1,1′-dionen erhalten. Ringschluß von 6 führt zu Diastereomeren (cis- und trans-7), die nach schonender Abspaltung von Cr(CO)3 die enantiomeren Biindanone 8 liefern, aus denen die 2,2′-Spirobiindane 9 zugänglich sind. Chiralität und enantiomere Reinheit aller Spirane folgen aus jenen der eingesetzten Indanone 1. Dieses universelle Prinzip wird anhand einiger Methyl- und Methoxy-2,2y-spirobiindan-1,1′-dione und -biindane präsentiert.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100424
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  • 8
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Indols, VIII. Decarboxylierungen einiger 1-Alkyl-2-carboxy-3-indolessigsäuren sowie Synthese eines 5-Thiocyanato-2,3-dihydroindols (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3538-3542 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Not mentioned2a-d, easily produced from the N-alkyl-N-phenylhydrazines 1a-d and 2-oxoglutaric acid, are decarboxylated to the compounds 4a-d in high yields. 2a is reduced to the 2,3-dihydro compound 3a and reacts via the amide 5a to the 5-thiocyanato derivative 6a.
    Notes: Contributions to the Chemistry of Indole, VIII. Decarboxylations of Some 1-Alkyl-2-carboxy-3-indolacetic Acids and Synthesis of a 5-Thiocyanato-2,3-dihydroindole-d, leicht darstellbar aus N-Alkyl-N-phenylhydrazin und 2-Oxoglutarsäure, werden mit hoher Ausbeute zu 4a-d decarboxyliert. 2a wird zum Dihydroindol 3a reduziert und über das Amid 5a zum 5-Thiocyanatoderivat 6a umgesetzt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081115
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  • 9
    Electronic Resource
    Electronic Resource
    Dimeric Silver(I) Complexes of Some Isothiazole-Based LigandsDedicated to Prof. Dr. Rolf Gleiter on the occasion of this 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 95-100 
    Details
    ISSN: 0009-2940
    Keywords: Isothiazole complexes ; Dinuclear silver(I) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of isothiazole-based potential ligands bearing substituents with additional donor sites in the 5-position of the heterocycle was synthesized [3-Me-5-R-C3HNS; R = CH=N(CH2)2py (1), CH=NCH2py (2), CH2N(CH2CH2NEt2)2 (4), (CH2)2SMe (5)]. Upon reaction with AgO3SCF3 they formed complexes [(1)AgOSO2CF3]2 (6), [(2)AgOSO2CF3]2 (7), [(4)Ag]2+2(O3SCF-3)2 (8) and [(5)AgOSO2CF3]2 (9), respectively. 6, 8 and 9 were shown by X-ray structural analyses to consist of dimeric units L2Ag2+2, either discrete (8), coordinated by terminal CF3SO-3 units (6). In 8 and 9 the isothiazole moiety is bonded to the metal center via the ring-N. The coordination potential of the isothiazole heterocycle is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300115
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  • 10
    Electronic Resource
    Electronic Resource
    Pyrazolate-Based Oligonuclear Copper and Silver Complexes with N/S Coordination SpheresDedicated to Prof. Dr. Gottfried Huttner on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1441-1447 
    Details
    ISSN: 0009-2940
    Keywords: Pyrazolate complexes ; Bridging ligands ; Copper ; Silver ; N,S-Donor Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of pyrazole-based potential ligands bearing thioether substituents in 3- and 5-positions of the heterocycle was synthesized [3,5-bis(RSCH2)-pyzH R=Ph (1aH), PhCH2 (1bH), iPr (1cH), tBu (1dH)]. These ligands afford oligonuclear Cu1 and Ag1 coordination compounds [LCu]x (2a-c, L = 1a - c) and [LAg]x (3a-d, L = 1a-d), respectively. The single crystal X-ray analysis of 3c shows the presence of trimeric planar arrays of N,N′-bridging pyrazolates and linear coordinated silver ions, with each two of the trinuclear moieties being linked by two unsupported short intermolecular Ag…Ag contacts [3.041(1) Å]. Molecular-weight determinations for 2a (THF) and 3c (toluene) indicate that hexanuclear entities are preserved in solution. Starting from 1bH the CuII complex [(1b)2Cu2](BF4)2 (4) was synthesized. According to an X-ray crystal structure analysis it consists of dinuclear molecules with two bridging pyrazolates, distorted square planar N2S2 coordination spheres for Cu11 and an axially bridging tetrafluoroborate. Magnetic susceptibility data reveal an antiferromagnetic exchange (J = -206 cm-1) that is among the highest found for doubly pyrazolate bridged dicopper(II) complexes, which is rationalized on the basis of the rather symmetric dinuclear core of 4. The irreversibility of the electrochemical reduction and oxidation processes for the CuII and CuI compounds, respectively, is explained by the inability of the respective coordination framework to adapt to different geometric preferences.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301014
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