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  • Titanium
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  • Electronic Resource  (6,971)
  • Loose Leaf
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  • 1995-1999  (20)
  • 1960-1964  (6,355)
  • 1925-1929
  • 1880-1889  (596)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Trauma und Berufskrankheit 1 (1999), S. 307-319 
    ISSN: 1436-6274
    Keywords: Schlüsselwörter Fixateur-interne-Systeme ; Winkelstabilität ; Titan ; Osteosynthese ; Spondylodese ; Key words Internal fixator systems ; Angular stability ; Titanium ; Osteosynthesis ; Spondylodesis ; Locked screw plate interface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: The clinical use of internal fixator systems started in 1983 with angularly stable implants for treatment of injuries to the thoracic and lumbar spine, followed two years later by internal fixators in which the screw heads were locked through compression by small additional plates. In the following years, internal fixators of similar design were developed and successfully implanted for anterior spondylodesis of the cervical, thoracic, and lumbar spine. The first use of a special plate fixator for the thigh dates to 1993 with the additional development of a compression plate fixator for implantation in the distal femur. Addressing the need for internal fixator systems in body regions with little soft tissue, implants made out of titanium were developed that develop angular stability by exploiting the friction created by fixing self-tapping screws of harder titanium in plates made from softer titanium, thus creating a permanently stable bond that also enables various screw angles and positions. Implants were constructed for the upper and lower extremities as well as for the spine. Compression plate fixators have been used so far in 141 cases for injuries to the spine and in the femur in 73 cases. Angular stable interlocking plate systems employing the friction screw locking principle have been implanted in upper extremities in nine cases, in the lower extremities in 91, and in the spine in 18 cases. Biomechanical research has demonstrated the advantages of locked plate systems over plates without angular stability. Combined with the advantage of minimally invasive surgical approach for implantation, these improvements result in improved outcomes. Implant removal is uncomplicated. Implants must be especially designed when the construction principle is employed.
    Notes: Der klinische Einsatz von Fixateur-interne-Systemen begann 1983 mit winkelstabilen Implantaten für die dorsale Versorgung von Brust- und Lendenwirbelsäulenverletzungen. 1985 erfolgte der klinische Einsatz eines Druckplattenfixateurs für die Brust- und Lendenwirbelsäule. Nach diesem Prinzip wurden in den folgenden Jahren auch Fixateursysteme für die ventrale Spondylodese der Hals-, Brust- und Lendenwirbelsäule entwickelt und klinisch eingesetzt. Der Einsatz eines eigenen internen Plattenfixateursystems für den Oberschenkelbereich geht auf das Jahr 1993 zurück. Nach dem Druckplattenprinzip kamen auch interne Fixationssysteme für das distale Femur zur Anwendung. Für andere Körperregionen mit einer geringeren Weichteildeckung erfolgte die Konstruktion einer sich im Plattenloch selbst aufbauenden Winkelstabilität. Diese basiert auf einem Reibschluß von verschieden harten Reintitanmaterialien. Durch das Eindrängen eines gewindetragenden Schraubenkopfs aus einem härteren Reintitan in ein Plattenloch, welches aus einem weicheren Titan besteht, kommt es zu einer dauerhaft festen Verbindung. Diese Form der Winkelstabilität erlaubt eine unterschiedliche Schraubenpositionierung. Nach diesem Prinzip der Winkelstabilität erfolgte dann die Konstruktion von Implantaten, die für Ober- und Unterschenkel, Fuß, Arm, aber auch den Wirbelsäulenbereich geeignet sind. Nach dem Druckplattenprinzip überblicken wir 141 ventrale Wirbelsäulenoperationen sowie 73 Implantationen am Femur. Nach dem Prinzip des Gewindeformens mit Reibschluß implantierten wir 9 Systeme im Arm-, 91 im Bein- und 18 im Wirbelsäulenbereich. Die biomechanischen Untersuchungen zeigten, daß Implantate mit Winkelstabilität Vorteile gegenüber nicht winkelstabilen Implantaten besitzen. Die mechanischen Vorteile der Fixateur-interne-Systeme und schonende operative Methoden führen nach jetziger Einschätzung zu günstigeren Heilungsverläufen. Die Metallentfernung wird nicht behindert. Das Design der Implantate muß dem Konstruktionsprinzip angepaßt werden.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European food research and technology 209 (1999), S. 389-392 
    ISSN: 1438-2385
    Keywords: Key words Gelation ; Polymerization ; Whey proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The influence of protein concentration on the properties of gels obtained by a two-stage heating process was determined. In the first stage, whey protein dispersion (3–10%) was heated at pH 8.0, and in the second stage it was diluted to 3% protein, adjusted to pH 7.0 and heated again. Increased protein concentration in the first stage of polymerization resulted in the gels obtained in the second stage having a lower phase angle, increased storage modulus and increased hardness. Increased protein concentration also resulted in gels with an increased optical density, which suggests thathigher protein concentration leads to more and larger aggregates. Gels obtained from dispersions preheated at a higher protein concentration had higher permeability coefficient (B gel) values. The increase in B gel suggests that the higher protein concentration increased the size of the aggregates, which in a second stage of heating formed a gel matrix with a larger pore size.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1436-6274
    Keywords: Schlüsselwörter Unterschenkel ; Fixateur interne ; Minimalinvasive Operationstechnik ; Titan ; Key words Tibia ; Internal fixator ; Minimally invasive operation ; Titanium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Between September 1997 and July 1999, 42 tibia operations were performed on 40 patients using an internal titanium fixator. Twenty-three patients received fixation for pseudoarthrosis and three for malalignment corrections. Of 16 patients with tibial fractures, eight had been treated with temporary external fixators prior to implantation of the internal titanium fixator. No complications were noted intraoperatively. Postoperatively, a small soft tissue necrosis in one patient with peripheral arterial occlusive disease showed spontaneous healing. Other complications included peroneal nerve damage with complete recovery and an uneventful infection at the bone implant interface in a patient with a history of osteitis. Minimally invasive osteosynthesis was performed in 33 patients by making two small incisions and creating a subcutaneous tunnel. In 24 cases, a third incision was made and autologous spongiosa introduced at the fracture site. Local antibiotics were administered in 20 patients. At the time of follow-up, 24 patients were evaluated. No loss of correction and no hardware failures were noted. All patients demonstrated uneventful bone healing.
    Notes: Von September 1997 bis Juli 1999 wurden bei insgesamt 40 Patienten 42 Operationen mit einem Titanfixateur interne für den Unterschenkelschaft durchgeführt. In 23 Fällen erfolgte die Fixation bei Pseudarthrose, in 16 Fällen bei Unterschenkelfrakturen, davon in 8 Fällen als Umstieg vom Fixateur externe, und in 3 Fällen die Korrektur von Fehlstellungen. Intraoperativ traten keine Komplikationen auf. Postoperativ fanden sich 1 kleine, spontan abheilende Wundrandnekrose bei Durchblutungsstörung, 1 passagerer N.-peronaeus-Schaden und 1 blander Plattenlagerinfekt bei vorbestehendem ruhenden Infekt. Bei 33 Patienten erfolgte die Implantation minimalinvasiv über kleine Inzisionen und durch Untertunnelung der Weichteile. In 24 Fällen erfolgte die ¶Anlagerung autologer Spongiosa durch eine kleine 3. Inzision, bei 20 Patienten wurde gleichzeitig eine Refobacin-Palacos-Kette eingelegt. Zum Nachuntersuchungszeitpunkt waren 24 Behandlungen abgeschlossen. Ein Korrekturverlust oder Implantatversagen fanden sich nicht. Alle knöchernen Heilungsvorgänge erfolgten störungsfrei.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European spine journal 8 (1999), S. 151-155 
    ISSN: 1432-0932
    Keywords: Key words MR imaging ; Pedicle screw fixation ; Titanium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This series comprises ten patients treated with transpedicular screw fixation, who suffered early postoperative problems such as radicular pain or motor weakness. Besides plain radiographs, all patients were also evaluated with MR imaging. Three patients were reoperated for either repositioning or removal of the screws. MR images, especially T1-weighted ones, were very helpful for visualizing the problem and verifying the positions of the screws. In cases of wide areas of signal void around the screws, the neighboring axial MR images at either side, which have fewer artifacts, gave more information about the screws and the vertebrae.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-072X
    Keywords: Key words Thiamin ; Biosynthesis ; Prokaryotes ; Transport ; Kinase ; Mechanism ; Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twelve genes involved in thiamin biosynthesis in prokaryotes have been identified and overexpressed. Of these, six are required for the thiazole biosynthesis (thiFSGH, thiI, and dxs), one is involved in the pyrimidine biosynthesis (thiC), one is required for the linking of the thiazole and the pyrimidine (thiE), and four are kinase genes (thiD, thiM, thiL, and pdxK). The specific reactions catalyzed by ThiEF, Dxs, ThiDM, ThiL, and PdxK have been reconstituted in vitro and ThiS thiocarboxylate has been identified as the sulfur source. The X-ray structures of thiamin phosphate synthase and 5-hydroxyethyl-4-methylthiazole kinase have been completed. The genes coding for the thiamin transport system (thiBPQ) have also been identified. Remaining problems include the cloning and characterization of thiK (thiamin kinase) and the gene(s) involved in the regulation of thiamin biosynthesis. The specific reactions catalyzed by ThiC (pyrimidine formation), and ThiGH and ThiI (thiazole formation) have not yet been identified.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer-aided materials design 6 (1999), S. 311-321 
    ISSN: 1573-4900
    Keywords: Clustering ; Molecular dynamics ; Molecular statics ; Surface diffusion ; Titanium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper, we present a study of diffusion and clustering of atoms on the titanium (0001) surface using molecular dynamics and molecular statics methods. The formation energy of each defect cluster is calculated using a combination of annealing and quenching techniques. Diffusion mechanisms of clusters are elucidated by the analysis of atomic trajectories, and are confirmed by calculating energy states along the diffusion path and by fitting the diffusion coefficients to one or more Arrhenius functions. Our simulations show that the clusters diffuse by a sequence of atomic jumps; once an atom moves forward by half an atomic diameter, the others follow it. Such a correlated process involves an activation energy that is comparable to that of an adatom. Atoms in each cluster, especially those in clusters consisting of three and seven atoms, are tightly bound. However, due to high mobility, the clusters are less likely to be the critical nuclei in three-dimensional growth of thin films on the (0001) surface. Even the cluster consisting of seven atoms swaps a linear distance of 60 nm during the growth of one monolayer of thin film under typical deposition conditions and at room temperature, making it ineffective as a critical nucleus above room temperature.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 102 (1999), S. 285-292 
    ISSN: 1432-2234
    Keywords: Key words: Ethylene insertion ; ab initio MO calculations ; Sm complexes ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. Ethylene insertion into the Sm–C bond of H2SiCp2SmCH3, a model reaction of an olefin polymerization propagation step, has been studied by ab initio molecular orbital methods. The small electronegativity of the Sm atom makes the Sm–C bond ionic, the methyl group being negatively charged by −0.75. The reaction passes through a loose ethylene complex with a binding energy of 15 kcal/mol and then a tight four-centered transition state with an agostic interaction between the Sm atom and one of the methyl CH bonds. A small activation energy of 14 kcal/mol is required to pass through this transition state, indicating that this is an easy reaction. Compared with the reactions with group 4 cationic silylene-bridged metallocenes the activation energy is higher and the reaction is less exothermic. The origin of these differences is discussed. The results of molecular mechanics calculations on regio- and stereoselectivities in the insertion reaction of propylene are also reported.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1611-4663
    Keywords: Coriolus versicolor ; Na2SO3-HCHO-AQ pulping effluent ; Polymerization ; Lignosulfonate ; Laccase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A strain of the fungusCoriolus versicolor was inoculated periodically into potato dextrose agar (PDA) slants containing the effluent to enhance the natural ability to grow in the effluent. The acclimated strain grown in the 50% effluent-containing PDA slant and the original strain were employed to treat the effluent. The acclimated strain could grow in a higher concentration of the effluent than the original unacclimated one. Both the original and acclimated strains improved the dispersing ability of the effluent, especially the acclimated strain because of its higher laccase secretion. The dispersing ability of the SFP effluent was improved to a level comparable to a commercial lignosulfonate product because it was strongly polymerized by the fungus. During the fungal treatment, more than 50% of the sugars were removed from the effluent, thereby increasing the purity of the SFP lignin product.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1617-4623
    Keywords: Key words Bacterial polysaccharide ; Glycosyltransferase ; Acetan ; Acetobacter xylinum ; Biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Biosynthesis of repeat-unit polysaccharides and N-linked glycans proceeds by sequential transfer of sugars from the appropriate sugar donor to an activated lipid carrier. The transfer of each sugar is catalysed by a specific glycosyltransferase. The molecular basis of the specificity of sugar addition is not yet well understood, mainly because of the difficulty of isolating these proteins. In this study, the aceA gene product expressed by Acetobacter xylinum, which is involved in the biosynthesis of the exopolysaccharide acetan, was overproduced in Escherichia coli and its function was characterised. The aceA ORF was subcloned into the expression vector pET29 in frame with the S·tag epitope. The recombinant protein was identified, and culture conditions were optimised for production of the soluble protein. The results of test reactions showed that AceA is able to transfer one α-mannose residue from GDP-mannose to cellobiose-P-P-lipid to produce α-mannose-cellobiose-P-P-lipid. AceA was not able to use free cellobiose as a substrate, indicating that the pyrophosphate-lipid moiety is needed for enzymatic activity.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1435-1536
    Keywords: Key words Reaction kinetics in microgravity ; Colloidal silica spheres ; Polymerization ; Transmitted-light intensity ; Dynamic light scattering
    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 Polymerization reactions of colloidal silica spheres via the hydrolysis and dehydration processes of tetraethyl orthosilicate with ammonia and a tiny amount of water in ethyl alcohol have been studied in microgravity by the parabolic flights of a MU-300 rear-jet aircraft. Induction periods and polymerization rates are determined by fast-scanning transmitted-light-intensity measurements and the fast-scanning dynamic light-scattering method. Direct observation of the reaction mixtures is also made with a charge-coupled device video camera. Reproducible and reliable data are obtained in microgravity compared with those in gravity. Increases in the induction times and decreases in the polymerization rates are observed in microgravity compared with those in gravity. One of the main reasons for these observations is the fact that the translational Brownian movement of the reactants and/or product spheres is free from downward translational movement in microgravity. Very weak convection of the reaction suspensions in microgravity is another important factor.
    Type of Medium: Electronic Resource
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  • 11
    ISSN: 1435-1536
    Keywords: Key words Allyldimethyldodecylammonium bromide ; Liquid crystals ; Polymerization ; Polymerizable surfactant
    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 Allyldimethyldodecylammonium bromide was polymerized by γ-ray irradiation in both hexagonal and cubic mesophases, and the conversion–time curves were obtained. The maximum conversion was about 35%, and the polymer remained in the liquid-crystalline structure formed by the nonpolymerized monomers. The influence of polymerization on the distribution of water in the different types related to the hydrophilic surfaces of microstructures was studied using Fourier transform infrared spectroscopy. The incomplete polymerization was explained by steric constraints in the liquid-crystalline structures.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 277 (1999), S. 203-209 
    ISSN: 1435-1536
    Keywords: Key words Microemulsions ; Vinylacetate ; Acrylic acid structure ; Polymerization
    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 The composition ranges over which microemulsions are formed in systems containing vinyl acetate, acrylic acid, water with nonylphenol ethoxylated with 25 mol ethylene oxide monomaleate as surfactant were studied. Conductometric and refractometric investigations have shown the existence of some aqueous/organic, bicontinuous and organic/aqueous microemulsions. The types of precursor microemulsions influence the conversion of monomers. In the presence of a crosslinking agent, diethylene glycol bis maleate, hydrogels are formed whose water absorption depends on the composition of the initial microemulsions. The kinetics of water absorption suggests the modification of polymer network structures as a function of the crosslinked monomer content and the ratio of organic to aqueous phases.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1899-1904 
    ISSN: 1434-1948
    Keywords: Boron ; Titanium ; Zirconium ; Hafnium ; Metallocenophanes ; Metallocenophanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various [1]borametallocenophane complexes of all the group IV metals were obtained in high yield by a very efficient multistep, one-pot synthesis. By this method not only the biscyclopentadienyl and diindenyl complexes [{R2NB(η5-C5H4)2}MCl2] (M = Zr, R = Me, SiMe3, 4a, b; M = Hf, R = SiMe3, 5) and [{(Me3Si2)NB(η5-C9H6)2}MCl2] (M = Ti, 6; M = Zr, 7) were obtained, but also complexes with two different η5-coordinated ligands such as [{iPr2NB(η5-C5H4)(η5-C9H6)}MCl2] (M = Zr, 8; M = Hf, 9). Some of compounds 4-9 were chosen to investigate their catalytic properties with respect to Ziegler-Natta-type polymerisation of olefins, and proved to be highly efficient for the preparation of polyethylene.
    Additional Material: 2 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 69-73 
    ISSN: 1434-1948
    Keywords: Boron ; Titanium ; Metallocenophanes ; [1]Boratitanocenophanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper presents two methods for the synthesis of the first [1]boratitanocenophanes. The novel biscyclopentadienylborane [(Me3Si)2NB(C5H5)2], the dilithio salt Li2[(Me3Si)2NB(C5H4)2] (1) of which was characterized by multinuclear NMR methods, was prepared in situ, and served as starting material for several [1]boratitanocenophanes. [Cl2Ti{(C5H4)2BN(SiMe3)2}] (2) was obtained in high yield by a convenient one-pot synthesis starting from 1 and [TiCl3(thf)3], followed by oxidation with PbCl2. The highly reactive [(Me2N)2Ti{(C5H4)2BN(SiMe3)2}] (3) was obtained by the reaction of [(Me3Si)2NB(C5H5)2], prepared in situ, with Ti(NMe2)4and converted into the chloro derivatives [(Me2N)ClTi{(C5H4)2BN(SiMe3)2}] (4) and [Cl2Ti{(C5H4)2BN(SiMe3)2}] (2) by treatment with one or two equivalents of a suitable diaminochloroborane. All [1]boratitanocenophanes were characterized in solution by multinuclear NMR spectroscopy, and in addition the structure of 2 in the crystalline state was determined by a single-crystal X-ray study.
    Additional Material: 1 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1847-1849 
    ISSN: 1434-1948
    Keywords: Titanium ; Amino alcohols ; Metal alkoxide ; Oxo alkoxide ; Metallacycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ti6O6(MDEA)6·2CH2Cl2 (MDEA = N-methyldiethoxoamine) was obtained by the controlled hydrolysis of the Ti(MDEA)2 complex and analysed by X-ray diffraction. The compound consists of a ring of six [TiO5N] octahedra, edge bridged by μ2-oxide and a μ2-alkoxide arm of the aminoalkoxide ligand.
    Additional Material: 2 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1855-1857 
    ISSN: 1434-1948
    Keywords: Fullerenes ; Titanium ; Complexes ; X-ray analysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first fullerene complex of titanium Cp2Ti(η2-C60) has been synthesized by reaction of the bis(trimethylsilyl)-acetylene complex of titanocene Cp2Ti(η2-Me3SiC2SiMe3) with an equimolar amount of fullerene-60 in toluene at room temperature under argon. An X-ray diffraction study of the complex has shown that it has the structure of a titanacyclopropane derivative.
    Additional Material: 1 Ill.
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  • 17
    ISSN: 1434-1948
    Keywords: Ruthenium ; Triazole ; Titanium ; Electron Transfer ; Sensitizers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes [Ru(dcb)2(L)] {L = 3-(2-hydroxyphenyl)-5-(pyridin-2-yl)-1,2,4-triazole (2-ppt), 3-(4-hydroxyphenyl)-5-(pyridin-2-yl)-1,2,4-triazole (4-ppt), 3,5-bis(pyrazin-2-yl)-1,2,4-triazole (bpzt), 3-(2-hydroxyphenyl)-5-(pyrazin-2-yl)-1,2,4-triazole (2-ppzt) and dcb = 4,4′-(CO2H)2-2,2′-bipyridine} have been synthesized, spectroscopically characterized and anchored to nanocrystalline TiO2 electrodes for the conversion of light into electricity in regenerative solar cells. The different efficiencies observed have been rationalized on the basis of an analytical expression relating the incident photon-to-current conversion efficiency (IPCE) to the kinetic parameters of the relevant electron transfer processes involved in the solar cell.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 1434-1948
    Keywords: Germanium ; Nitrogen ; Silicon ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of dippNSiMe3Si(NH2)3 (1) (dipp = 2,6-iPr2C6H3) with Cp*TiMe3 (Cp* = C5Me5) and Me3SnCl yields the new heterocyclic adamantane (dippNSiMe3Si)2(Cp*Ti)2(NH)6 (2) containing the Si2Ti2(NH)6 core and the silicon-nitrogen six-membered ring compound [dippNSiMe3Si(NH2)NH]3 (4). [dippNSiMe3Ge(NH2)2]2NH (5) reacts with AlMe3 to give the germanium-nitrogen six-membered ring compound [dippNSiMe3Ge(NH2)NH]3 (6). The compounds 2, 4 and 6 have been structurally characterized by single-crystal X-ray structural analysis.
    Additional Material: 3 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2135-2145 
    ISSN: 1434-1948
    Keywords: Density functional calculations ; Epoxidation ; Peroxo complexes ; Titanium ; Transition states ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Epoxidation of olefins by TiIV peroxo and hydroperoxo (alkylperoxo) complexes was investigated using a hybrid DFT method (B3LYP). Reaction energies and activation barriers for direct oxygen transfer to ethylene as a model olefin were computed for various model complexes to compare the epoxidation activity of Ti(η2-O2) and TiOOR (R = H, CH3) moieties. The activity of complexes with a Ti(O2) peroxo group is shown to be essentially quenched when the coordination sphere of the complex is saturated by strongly basic (σ-donor) ligands. In contrast, the activity of a TiOOH functional group depends only weakly on the saturation of the coordination sphere of the Ti center. Substitution of methyl for hydrogen in a TiOOH group is found to slightly increase the activation barrier of epoxidation. The computational results give preference to reaction paths that involve TiOOR species. The factors governing the activity of Ti(O2) and TiOOR groups, in particular the effects of donor ligands, are discussed on the basis of a molecular orbital analysis.
    Additional Material: 9 Ill.
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  • 20
    ISSN: 1434-193X
    Keywords: Aldol reactions ; Titanium ; Asymmetric synthesis ; Bis(enolates) ; Tetrahydropyran-2,4-diols ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new metal-directed (Ti, Zr, Al, In, Sn) domino aldol-aldol hemiacetal reaction is presented that can be used for the highly stereoselective de-novo synthesis of tetrahydropyran-2,4-diols containing five stereogenic centers.
    Additional Material: 3 Tab.
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  • 21
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 1-8 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of electrophoresis experiments on aqueous solutions of native and thermally denatured DNA are reported. A significant decrease of the electrophoretic mobility has been observed following thermal denaturation, which under suitable conditions gives rise to a resolution into two peaks of 1 : 1 mixtures in the electrophoretic pattern. This result is entirely consistent with the previously reported increase of the activity coefficient of sodium counterions following thermal denaturation. The hypothesis that thermal denaturation of calf thymus DNA induces a large decrease of charge density on the macroion which has been ascribed to the population of more extended conformations of the chains in the disordered region of the molecule is therefore further confirmed.
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  • 22
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the depolymerization of native dextran in dilute hydrochloric acid at different temperatures has been followed by measurements of M̄w, M̄n, [η], 〈ρ2〉1/2, and S. The data allow the correlation of the various parameters of the total hydrolyzate at various degrees of depolymerization. At a first approximation the results conform to a random splitting of a statistical, branched polymer.
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  • 23
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The γ-ethyl-L-glutamate NCA polymerization initiated by di-n-butyl and di-isopropyl amine was studied. The experimental kinetic curves show an autocatalytic portion with 25-30% conversion, followed by a pseudo first-order region which extends up to at least 85-90%. In this linear region, the reaction order appears to be 0.5 in initiator with both amines. High degrees of polymerization and high reaction rates were observed. These results are similar to those obtained in the γ-benzyl-L-glutamate NCA polymerization initiated by sodium methoxide.
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  • 24
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dielectric constant and the electric birefringence of poly-γ-benzyl-L-glutamate in ethylene dichloride-dichloroacetic acid mixtures have been measured as functions of the solvent composition. These properties undergo a marked decrease with the addition of a small amount of dichloroacetic acid, as well as an abrupt change accompanying the helix-coil transition in the vicinity of 75 vol.-% dichloroacetic acid. The former is attributed to the apparent diminution of the dipole moment of helical poly-γ-benzyl-L-glutamate molecule, which may be due to the protonation of terminal amide groups.
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  • 25
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    Biopolymers 2 (1964) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 26
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of γ-benzyl-L-glutamate NCA initiated by n-hexylamine in DMF proceeds with two successive propagation rates whose ratio is about 1.5. The onset of the increase in rate of propagation occurred at a DPn of 7-14, which was independent of initiator to anhydride ratio and anhydride concentration and not a result of anhydride impurities. The increase in rate is likely a result of a conformational change in the polymer at a DPn of 7-14.
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  • 27
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    Biopolymers 2 (1964), S. 147-161 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The NCAs of the N-benzyl derivatives of β-alanine, β-DL-aminobutyric acid, and β-DL-aminoisobutyric acid (nonplanar six-membered rings) were prepared by reacting the corresponding N-chloroformyl derivatives, obtained on reaction of the N-benzyl amino acids with phosgene, with triethylamine. Contrary to the others, the NCA of N-benzyl-β-alanine polymerized readily on heating in vacuo or in solution, using n-hexylamine or methanolic sodium methoxide as initiators. With n-hexylamine the molecular weights of the polymers obtained in benzene, dioxan, and dimethylsulfoxide, were in accordance with DP = [NCA]/[Initiator], as was found with conventional five-membered ring NCAs of α-amino acids. With sodium methoxide initiation, DPs of the polymers obtained were smaller than the (NCA)/[Initiator] ratio, contrary to what was found previously with α-amino acid NCAs. The possibility that stereochemical factors are responsible for the differences in polymerization activity of various. N-alkyl β as well as α amino acid NCAs is discussed.
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  • 28
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    Biopolymers 2 (1964), S. 231-236 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrophoretic mobility of DNA in the presence of tetramethylammonium and alkali metal ion chlorides has been studied as a function of ionic strength. Each cation exhibits a characteristic behavior in accord with the idea that the order of inter-action with DNA is Li+ 〉 Na+ 〉 K+ 〉 TMA+. The application of theories of the electrophoresis of polyelectrolytes is discussed, leading to an attempt to calculate the fractional charge per DNA phosphorus from the mobility data. Over the range 0.05-0.4M a constant and unique value of the DNA charge is obtained in the presence of each cation. Values of the zeta potential and of the friction factor per monomer unit are also calculated.
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  • 30
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    Biopolymers 2 (1964), S. 135-146 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple quantitative theory of inactivation of transforming DNA has been formulated. It is based on the idea that genetic recombination of the molecule of transforming DNA with the bacterial genome is possible only, from the point mutation of the gene up to the nearest hit or point of damage on the corresponding DNA molecule. Our data and the data of other authors on the kinetics of inactivation by HNO2 or U.V. light or both are consistent with these theoretical predictions. Theoretical predictions were made concerning the extent of reactivation by fusion mid annealing of damaged DNA with a diluting genetically inactive DNA. These estimates have been reasonably confirmed by our experimental results.
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  • 31
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    Biopolymers 2 (1964), S. 15-25 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to study the effect of glucose substitution on the sedimentation velocities of the T-even phage DNA's, T2 and T2*, and T6 and T6* bacteriophages were grown with H3and P32 labeling. Zone sedimentation of the DNA's isolated from these phagea showed that the glucosylated DNA's from both T2 and T6 sediment faster than the nonglucosylated molecules. Nonglucosylated DNA from TG and T2 phages sedimented with the same velocity, suggesting that the molecules of these phages are of the same length.
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  • 32
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    Biopolymers 2 (1964), S. 43-49 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report a simple method for measuring partial specific volumes, of polymers in dilute solutions with an accuracy of 3 parts per thousand. This method has been applied to 7 polypeptides in 4 organic solvents. The residue volumes deduced from these data are compared to those calculated by a differential method. The discrepancy is generally of the order of 1.5%.
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  • 33
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    Biopolymers 2 (1964), S. 283-286 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 34
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    Biopolymers 2 (1964) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 35
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the formation of the three-strand poly (A + 2U) complex is accompanied by a decrease in optical absorbance at 280 mμ, while the format ion of poly (A + U) is not. This difference makes it possible to demonstrate that in dilute solutions (∼10-4 monomolar), a 1 : 1 mixture of poly A and poly U always forms poly (A + U) at room temperature. At higher temperatures in solutions containing more than about 0.2M sodium ion, poly (A + U) is converted to poly (A + 2U) and free poly A. These results are consistent with the observations reported by Miles and Frazier, using infrared absorption spectra, at much higher polymer concentrations. It is concluded that most of the physicochemical studies of 1 : 1 mixtures of poly A and poly U in dilute aqueous solution refer to the two-stranded species.A simple thermodynamic analysis is developed to explain the two- to three-strand conversion, and with the use of a “phase diagram” showing conditions of stability of the various poly A-poly U structures as a function of salt and temperature, it is possible to estimate the value of the enthalpy of formation of poly (A + 2U).
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  • 36
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    Biopolymers 2 (1964), S. 337-347 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a chromatographic technique, the adsorption of the polyribonucleotides s-RNA and poly-A provided with tri-n-butylammonium ions from an aqueous solution on to the surface of polymeric hydrocarbon granules has been demonstrated. The aqueous solution from which adsorption takes place is the aqueous phase which results on agitating together n-butanol (100), water (130), tri-n-butylamine (10), n-butyl ether (10), and glacial acetic acid (2.5) (parts by volume). Microporous polyethylene granules, microporous fluorinated polyethylene granules, and solid grains of polyethylene powder have been employed as adsorbents. The adsorbed polyribonucleotides could be eluted by aqueous solutions of sodium chloride, urea, or triethylammonium acetate. s-RXA with tri-n-butylammonium counterions could also be adsorbed on polymethacrylic acid in tri-n-butylammonium form and eluted therefrom with aqueous urea solutions. It is considered that the adsorption from aqueous solution of polyribonucleotides with tri-n-butylammonium counterions on polymeric hydrocarbon surfaces is mediated by hydrophobic bond formation. Van der Waals forces may also contribute to the bonding. It is suggested that studies on the adsorption of polynucleotides provided with counterions: possessing nonpolar groups at an aqueous solution-polymeric hydrocarbon interlace may permit the elaboration of experimental systems to serve as models for the evaluation of the role of hydrophobic and van der Waals bonding forces in the interaction of polynucleotides with cell membrane surfaces.
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  • 37
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    Biopolymers 2 (1964), S. 395-398 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 38
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    Biopolymers 2 (1964), S. 361-380 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deoxyribonucleic acids (DNA's) extracted from several biological sources have been studied by means of the flow dichroism method, using the transparent coaxial cylinder apparatus. This study has two purposes: (1) to make clear the hydrodynamic behavior of the DNA chain, and the regularity in the orientation of purine and phrimidine bases about the molecular axis; and (2) to develop this particular flow dichroism method as an established device for the study of chain regularity of DNA and other chain polymers. The velocity gradient dependence of dichroism agrees well, to a first approximation, with the behavior of a model of a hydrodynamically equivalent ellipsoid in revolution. Differences between theoretical and empirical curves have been tentatively ascribed to the flexibility of the chain under consideration. Two kinds of data, 1 lie rotary diffusion coefficient and internal dichroism, have been evaluated by a graphical device in which the double logarithmic plots of reduced dichroism and velocity gradient of flow are compared with the theoretical curve. The data obtained have shown good reproducibility for DNA samples prepared by the same method from the same biological source. However, a remarkable difference in internal dichroism and rotary diffusion constant has been observed between DNA groups of different biological origin. The difference may be caused by fragmentation of DNA during the deproteinization procedure, bill the possibility that some of these differences originate in the biological source of the DNA cannot be denied. Orientation of purine and phrimidine bases in aqueous solution is found to be quite regular in direction, as predicted by the Watson-Crick model. Dichroic spectra have shown that the direction of the oscillator dipole corresponding to the 260 mμ absorption band has a different angular relationship to the helical axis than the oscillator dipole for the 220 mμ band.
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  • 39
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    Biopolymers 2 (1964), S. 381-393 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study of the super helical structure of synthetic polypeptides, such as poly-γ-benzyl-D (or L)-glutamate (PBDG or PBLG) was carried out. The PEG was dissolved in dimethylformamide (DMF). The solution was either allowed to remain at room temperature for a long time or poured into some fatty acid, such as formic acid, acetic acid, propionic acid, or caprylic acid. Whether the polymer precipitated slowly or rapidly depended upon the aging of the solution or the nature of the acid used. The precipitated gels revealed the coiled coil fibrils, but the feature and degree of coiling varied, depending upon the length of aging or the nature of the acid used for precipitation. After a short aging of the solution, there was no helical structure in the gels. After long aging, very fine-coiled coil macrofibrils or small spindle-like fibrils were obtained. The macrofibrils consisted of the spindle-like fibrils which in turn consisted of microfibrils (diam. 60-70A.). When using the fatty acid precipitation very fine to medium fine super helices were obtained. Extremely fine super helices were obtained in propionic acid. In these gels the PBG chains have an α-helical conformation. When PMLG-DCA solution was stored for a long time, another type of precipitation was obtained, one giving evidence of so-called cross-β crystallization and no coiled coil fibrils. The precipitation of cross-β fibrils was obtained when the concentration of the solution was above 8%.
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  • 40
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    Biopolymers 2 (1964) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 41
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    Biopolymers 2 (1964), S. 399-413 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titration studies of the 1 : 1 helical polynucleotide complex of polyinosinic acid and polycytidylic acid reveal that these two polymers form a complex when the polycytidylic acid is protonated near pH 3. Sedimentation studies show that the protonated complex also has a 1 : 1 stoichiometry. However, the protonated complex is more stable than the unprotonated neutral complex as judged by its thermal stability. The molecular structure of the protonated complex is not the same as the neutral form. Study of the kinetics of the reaction of the protonated complex with formaldehyde suggests that the amino group of cytosine is involved in hydrogen bonds which hold the polynucleotide strands together.
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  • 42
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    Biopolymers 2 (1964), S. 415-444 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The protein sequences now known have been reconstructed as a kind of intriguing logical-mathematical puzzle using information about fragments of the molecules. We wish to show that the reconstruction can be done systematically by repeating a series of elementary operations on these same data governed by a set of well-defined rules. The completely automatic reconstruction of polymer sequences by a high speed digital computer using these operations and rules is demonstrated.
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  • 43
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of the renaturation of DNA molecules is examined on the basis of the bimolecular interaction of Gaussian chain polymers. In the nucleus formation by hydrogen bonding in segment-segment interaction, two types of interchain interaction, that is, one between complementary chains and one between noncomplementary chains, and one noncomplementary intrachain interaction are considered to be, in competition. Several previously observed characteristics of the renaturation process are displayed by this simple model. In particular it accounts for the dependence of the extent of renaturation on the heterogeneity, molecular weight, and radius of gyration of DNA, and of the ratios of the reaction rates between complementary and noncomplementary segments. Among these variables the ratio of reaction rates has shown to have a quite specific value, as high as the order of 104, which favors the complementary-strand interaction. This very great bias in favor of complementary strand interaction emphasizes that the renaturation phenomena displays the same character of biological specificity that is associated with enzyme-substrate interaction or antigen-antibody interaction. Moreover, since DNA is a good example of a one-dimensional system, it seems to provide a suitable clue for pursuing the analysis of pattern recognition at the macromolecular level.
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  • 44
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    Biopolymers 2 (1964), S. 463-481 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of DL-β-Phenylalanine N-carboxy anhydride adsorbed on polysarcosine dimethylamide has been studied further. This unusual reaction, which is analogous kinetically to reactions catalyzed by enzymes, was called the “chain-effect.” For polymerization of N-carboxy anhydrides by this mechanism it is necessary that the initiating polymer should possess an adsorption site and a terminal base group. The effect is shown to occur with simple compounds such as amino acid dimethylamides but not with poly-L-proline due to the inability of this polymer to adsorb the anhydride. From a study of the reaction of block copolymers of L-proline and sarcosine with DL-β-phenylalanine it is concluded that the relative positions of the adsorption site and terminal base group do not greatly influence the reaction rate, but the accessibility of the adsorption sites is an important factor determining the reactivity of polysarcosine dimethylamides of various degrees of polymerization (n). At high values of n the polymer exists in a coiled form and only those sites close to the terminal base group participate in the reaction. Initial rate studies give a detailed description of the early stage of the chain-effect polymerization. With these data and by use of analog computer techniques the complete reaction has been studied. It is concluded that the poly-DL-β-phenylalanine block produced is not permanently attached to the polysarcosine chain by hydrogen bonds during its formation but that an equilibrium exists between the polysarcosine and the poly-DL-phenylalanine blocks.
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  • 45
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Del Re's method for the study of saturated compounds has been adapted so as to deal with the σ-framework of conjugated molecules. This modified procedure is used in evaluating the σ-contribution to the dipole moments of the nucleic bases and of the A-T and G-C base pairs and also to the free energy change in the tautomeric, equilibria of the bases. Associated with an appropriate Hückel method for evaluating the π-contribution, the results obtained predict a small resultant moment for A-T versus a large moment for G-C. The energy calculations predict the keto and amino forms of the bases to be the most stable forms and cytosine to be the most easily involved in tautomeric shift to the rare form.
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  • 46
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    Biopolymers 2 (1964) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 47
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Temperature jump measurements employing optical rotation to follow transients show an upper limit of 10μsec. on the half time of the helix-random coil relaxation in poly-α, L-glutamic acid. No relaxations are observed under conditions where the polymer exists in completely helical or completely random coil form. Assuming that the helix-coil transition can be described kinetically as a pure growth process, expressions for the relaxation time are derived for three special cases. A comparison is made between the rate of the helix-coil transition and the rate of imide proton exchange.
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  • 48
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    Biopolymers 2 (1964), S. 501-501 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 49
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    Biopolymers 2 (1964), S. 561-574 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Numerical calculations have been done on the exciton spectrum of a schematic model of a linear polymer. The model consists of a random sequence of two kinds of subunit whose energy levels and transition moments are almost, but not quite, the same. The orders of magnitude of parameters are taken from DNA, but the full helical geometry has not been considered. Results are given for the density of energy levels, the dipole transition strength per unit energy, and the distribution of excitation energy along the polymer in individual states. A number of localized exciton states were found.
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  • 50
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    Biopolymers 2 (1964) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 51
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    Biopolymers 2 (1964), S. 9-14 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A calculation based upon Gorin's equation for the electrophoresis of a rigid cylinder is used to compare the available results of electrophoresis and membrane equilibrium experiments on DNA. The distribution of chloride ions across a membrane impermeable to DXA is considered. For a reasonable choice of parameters, agreement within about 2% is obtained between the values calculated from electrophoresis and the results of membrane equilibrium studies over a twenty-fold range of NaCl concentration.
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  • 52
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Light-scattering, sedimentation, viscosity, and reducing power measurements have been carried out on a sample of native dextran from Leuconostoc mesenteriodes B-512. The results are discussed in relation to the structure, polydispersity, and branching of the polysaccharide. The effect of different solvents on the behavior of native dextran has been studied. The molecular weight of the dextran remains unchanged in all the solvents used, while the radius of gyration shows a significant increase in some of them (concentrated salts, urea, and glucose solutions); in water-methanol solutions the radius of gyration slightly decreases.
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  • 53
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    Biopolymers 2 (1964), S. 65-68 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The statistical mechanical theory of the helix-coil transition of DNA has been recently discussed by one of the authors, who considered an assembly of DNA molecules with a Markoff distribution of nucleotide sequences. The present communication improves upon the above mentioned theory by introducing approximate normalization factors for the unnormalized statistical weights of finding a given molecule of the assembly in a given microscopic state.
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  • 54
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    Biopolymers 2 (1964), S. 103-103 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 55
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    Biopolymers 2 (1964), S. 79-89 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of small quantities of metal ions on the electrophoretic mobility of calf thymus DNA in solutions maintained at 0.2 ionic strength with weakly interacting (CH3)4N+ ions yields information about interactions occurring in a region very close to the polymer chain. By means of this technique, it is demonstrated that the binding order to DNA is Li+ 〉 Na+ 〉 K+ for the alkali metal ions and Mn++ 〉 Mg ++ 〉 Ca++ for the divalent ions studied. The quantitative details are compared to earlier work on the long-chain polyphosphates. Close agreement between the two systems is obtained indicating that an intrinsic property of individual phosphate groups is being observed and that minor discrepancies probably arise from secondary factors. Three types of stability constants representing the binding of alkali metal ions to DNA are calculated and although differing in absolute magnitude, they all satisfactorily represent the result that the order of interaction is Li+ 〉 Na+ 〉 K+ with respective relative strengths of 1.5 : 1 : 0.8.
    Additional Material: 2 Ill.
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  • 56
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    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 113-121 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Birefringence relaxation times on removing the electric field characterize the rigidity of a flexible linear macromolecule structure. Electrical birefringence investigation of DNA solutions supports this view. This principal regularities displayed by relaxation times of electric birefringence decay curves in solutions of chain macromolecules are considered.
    Additional Material: 6 Ill.
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  • 57
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 186-189 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: m-Dinitro-benzol und einige seiner Derivate (I, II, VII) lassen sich durch aufein-anderfolgende Einwirkung von Alkylmagnesiumhalogeniden, Methylamin/Formaldehyd und Essigsäure zu Mannich-Verbindungen von Dinitrodialkylcyclohexenen (Vb-e, VIII) umsetzen.
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  • 58
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 132-139 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Brom-cyclo-penten,-hexen und-hepten reagieren mit Lithiumaluminiumhydrid unter Bildung der jeweiligen cyclischen Monoolefine. Ann substituierten 3-Brom-cyclohexenen wurde gezeigt, daß die Reaktion sowohl als einfache nucleophile Substitution des Broms durch Wasserstoff als auch unter Allylumlagerung mit Angriff des Hydridions am C-Atom 1 verläuft. Die in beiden Allylstellungen bromierten cyclischen Olefine reagieren mit Lithiumaluminiumhydrid unter Bildung mehrerer Produkte, die durch Angriff des Hydrids an einem halogentragenden C-Atom (a), an einem olefinischen C-Atom (b) und an einem Brom-atom (c) entstanden sind. Reaktion (a) liefert Monoolefin, (b) ergibt 4-Bromolefin und nach (c) entsteht 1.3-Diolefin. Die Eliminierung nach (c) wurde allerdings nur am unsubstituierten Cyclohexen- und Cycloheptendibromid beobachtet. Für die Eliminierung wird ein weitgehend koplanarer Übergangszustand angenommen, der bei den anderen untersuchten Dibromiden nicht möglich ist.
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 165-168 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Desaminierung des 9-Amino-Δ4(10)-octalins in essigsaurer Lösung gibt zu etwa 80% die substituierten Allylalkohole Δ9(10)-Octalol-(1) und Δ4(10)-Octalol-(9) nebst Acetat, sowie die aus diesen durch normale Wasserabspaltung hervorgehenden Hexaline.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 179-185 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Umsetzung von β-Phenäthylmercaptan mit Aldehyden und Chlorwasserstoff entstehen [α-Chlor-alkyl]- β-phenäthyl-sulfide, die mit Aluminium-chlorid unter Ringschluß zu Isothiochromanen reagieren. - 1-Chlor-isothio-chroman, durch Einwirkung von Chlor auf Isothiochroman gewonnen, liefert mit Alkyl- oder Arylmagnesiumhalogeniden 1-Alkyl- bzw. 1-Aryl-isothiochromane, mit Mercaptanen 1-Alkylmercapto-, mit sekundären Aminen 1-Di-alkylamino- und mit Alkoholen 1-Alkoxy-isothiochromane. - Durch Umsetzung der letzteren mit Natriumhydrogensulfit entsteht Isothiochroman-sulfonsäure-(1), die in Isothiochroman-S-dioxid-sulfonsäure-(1) bzw. deren Ester übergeführt werden kann.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 218-224 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1.2-Benzpyren gibt der Bromierung das 5.8-Dibromderivat II und bei der Chlorierung das 3.5.8.10-Tetrachlorderivat V. Aus II wird das 5.8-Dinitril III und daraus die entsprechende Dicarbonsäure IV dargestellt. Die Hydrierung des 1.2-Benzpyrens führt zunächst zu einer Hexahydroverbindung, die ein Anthracenderivat ist, und dann zu dem Decahydro-1.2-benzpyren VI, das einen Naphthalinkern enthält. Die Oxydation verläft sehr komplex und liefert neben dunklen Kondensationsprodukten nur geringe Mengen zweier Säuren, die bei der Decarboxylierung Phenanthren und Triphenylen geben. - 3.4-Benzpyren liefert unter milden Bedingungen das 5-Brom-Derivat VII. Weitere Chlorierung von Trichlor-3.4-benzpyren VIII führt zum Trichlor-3.4-benzpyren-tetrachlorid IX.
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  • 62
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 249-254 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Produkte des Zerfalls der 1.2-Benzo-cyclenyl-(4)-diazonium-lonen (II) in Essigsäure werden mit denen der Acetolyse der 1.2-Benzo-cyclenyl-(4)-tosylate (VI) verglichen. Die erste Reaktion vollzieht sich am Beispiel des Vertreters mit 7-gliedrigem Ring mit 53-proz., die zweite mit 89-proz. Konfigurationserhaltung.
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  • 63
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 282-284 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thioschwefelsäure läß sich mit Thionylchlorid in guten Ausbeuten unter Chlorwasserstoffabspaltung zu einem äquimolaren Gemisch aus Disulfan-disulfonsäure und Trisulfan-disulfonsäure oxydieren. Mit Sulfurylchlorid bildet H2S2O3 neben HCI und Schwefeldioxid reine H2S4O6.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 285-294 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4.5.8-Trihydroxy-6-mercapto-chinolin-carbonsäure-(2) (II) wird durch Spaltung des Xanthogenats XV mit Aluminiumbromid dargestellt. Die Spaltung von XV mit Bromwasserstoffsäure führt zur reduktiven Abspaltung der Schwefelfunktion. Bei der Methylierung von II mit Diazomethan entsteht neben dem vollmethylierten Chinolinderivat XXI ein Chinolon XXII, bei dem die zur Chinolon-Carbonylgruppe peri-ständige 5-Hydroxygruppe unmethyliert bleibt. II ist wider Erwarten nicht identisch mit einem aus dem Ommochrom „Ommin A“ dargestellten Abbauprodukt.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 300-301 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 307-311 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Oxydation von Pyrogallol in alkoholischer Lösung wird Purpurogallincarbonsäure-(9)-ester gebildet, dessen Konstitution sich aus dem Abbau zu Purpurogallin und Methylterephthalsäure ergibt.
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  • 67
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 312-324 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1′.2′-Dihydroxy-benzotropolon-Derivate können nach zwei Methoden dargestellt werden: 1.aus 3 Moll. eines o-Benzochinons mit unsubstituierter Doppelbindung und 1 Mol. eines geeigneten Pyrogallolderivates, 2. durch Oxydation eines Gemisches geeigneter Brenzcatechin- und Pyrogallolderivate mit KJO3 bzw. K3[Fe(CN)6]. Bei der Umsetzung von o-Benzochinonen mit 4-Methylpyrogallol wird nur dasjenige Isomere (I a) gebildet, bei welchem die Reaktionspartner im Orientierungskomplex die räumlich günstigste Anordnung (Methylgruppe auf der von der Verknüpfungsstelle abgewandten Seite) haben. Zwei Synthesen für Trimethylpyrogallol und die Darstellung von 2′-Hydroxy-benzotropolon-chinon-(1′.4′) (VIII) werden beschrieben.
    Additional Material: 2 Tab.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 349-362 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: symm. Tetra-pyrenyl-(3)-äthan (III), symm. Di-pyrenyl-(3)-diphenyl-äthan (VII), 2.3-Di-[pyrenyl-(3)]-butan (IX), 2.2.5.5-Tetramethyl-3.4-diphenyl-3.4-di-[pyrenyl-(3)]-hexan (X) und Hexa-pyrenyl-(3)-äthan (XI) wurden dargestellt und ihre Fähigkeit zur Dissoziation in Radikale bei Raumtemperatur mit Hilfe der Elektronenspinreasonanz -Method (ESR) untersucht. Mit Ausnahme von 2.3-Di-[pyrenyl-(3)]-butan sind sämtliche der untersuchten Verbindungen bei Raumtemperatur partiell, das Hexa-[pyrenyl-(3)]-äthan erwartungsgemäß quantitativ dissoziiert. Beim symm. Tetra-α-naphthyl-äthan (VIII) ist dagegen keine Radikaldissoziation nachweisbar. - Das von Pyren ausgehend in guter Ausbeute in zweistufiger Synthese darstellbare symm. Tetra-pyrenyl-(3)-äthan ist im organischen Solvens bei Raumtemperatur unlöslich. Es ist im festen Zustand zu 0.0025% in Radikale dissoziiert. - Die Abhängigkeit der Carbonylfrequenz im IR-Spektrum von Mono- und Diarylderivaten des Formaldehyds vom Kondensationsgrad des Arylrestes wurde untersucht.
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 390-395 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Halogen-pyridazine reagieren mit Anthranilsäure oder Anthranilsäure-äthyl-ester zu Pyridazino[3.2-b ]chinazolonen-(10), deren Eigenschaften beschrieben werden.
    Additional Material: 1 Tab.
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  • 70
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 382-389 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei Eliminierung des Chlors aus cis-3.4-Dichlor-cyclobuten mittels Natriumamalgam in äther. Lösung entsteht das syn-Tricyclo[4.2.0.02.5]octadien-(3.7) (I), identisch mit dem früher aus 1.2.3.4-Tetrabrom-cyclobutan erhaltenen Produkt. Bei ähnlicher Behandlung mit Lithiumamalgam bildet sich überwiegend das isomere anti- Tricycloocatadien (II). Die Ozonspaltung und einige Derivate dieser Kohlenwasserstoffe werden beschrieben.
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  • 71
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 415-418 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Umsetzung von L-Tryptophan mit D-Fructose liefert kristallisierte 2-Nα-L-Tryptophan-2-desoxy-D-glucose(I), mit D-Glucose 1-Nα-L-Tryptophan-1-desoxy-D-fructose (II), Aus L-Histidin und D-Fructose entsteht 2-Nα-L-Histidin-2-desoxy-D-Glucose (II).
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  • 72
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 426-432 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Umsetzung der Hexacarbonyle der Chromgruppe mit Bipyridyl-(2.2′) bzw. 1.10-Phenanthrolin geht die Substitution über die Tetracarbonylstufen M(CO)4bipy bzw. M(CO)4phen hinaus, wenn man in hochsiedenden Kohlenwasserstoffen, wie Decalin, Tetralin oder 1-Methyl-naphthalin arbeitet. Während mit Mo(CO6 und W(CO)6 die Dicarbonylverbindungen M(CO)2bipy2 bzw. M(CO)2phen2 gebildet werden, entstehen mit Cr(CO)6 die totalsubstituierten Typen Cr(bipy)3 und Cr(phen)3.
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  • 73
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Hexacarbonyle M(CO)6 (M=Cr, Mo, W) setzen sich bei 120° mit flüssigem NH3 zu den Tricarbonyltriamminverbindungen M(CO)3(NH3)3 um; nur beim Cr(CO) 6 ist bei 80° auch Cr(CO)5NH3 zugänglich. Bei den Reaktionen von M(CO)4bipy und M(CO)4phen (bipy = Bipyridyl-(2.2′), phen = 1.10-Phenanthrolin) mit flüssigem NH3 erfolgt bei 120° Substitution einer CO-Molekel unter Bildung der Verbindungstypen M(CO)3 bipyNH3 bzw. M(CO)3phenNH3. Bei den Umsetzungen von M(CO)4bipy mit Kaliumcyanid in flüssigem NH3 wird bei 60° bipy vollständig durch CN⊖ ersetzt. Hierbei werden mit Cr(CO)4bipy K2[Cr0(CO) 4(CN)2], mit Mo(CO)4bipy und W(CO)4bipy unter gleichzeitiger CO-Substitution K3[M0(CO) 3(CN)3] gebildet.
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  • 74
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 472-479 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aryl- und Alkylisocyanate reagieren mit Benzolderivaten unter Friedel-Crafts-Bedingungen zu N-substituierten Benzoesäureamiden. Auch die wenig reaktionsfähigen Halogenbenzole sind der Umsetzung zugänglich.
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 563-565 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das kürzlich als 2-Hydroxy-4.5-epoxy-6-O-methyl-tetrahydro-apogalanthamin beschriebene Abbauprodukt aus Galanthamin wurde als (-)-Epigalanthamin identifiziert.
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  • 76
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 579-587 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wegen der zentralen Stellung der Chinonmethide in der Chemie des Lignins wurden 3 niedermolekulare p-Chinonmethide auf ihre chemischen Reaktionen und ihre Polymerisation untersucht. Die Polymerisate sind zur monomeren Stufe abzubauen und bestehen aus fortlaufend verätherten p-Hydroxy- benzyl-alkoholen (Polybenzylaryläthern) vom Typus XX.
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 602-609 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die cis-Formen geometrischer Isomerenpaare scheinen ganz allgemein energie ärmer zu sein, wenn nicht H-H-Wechselwirkung oder extreme Raumbeanspruchung wie beim 1.2-Dijod-äthylen vorliegen. Die Isolierung der geometrischen Isomeren der im Titel genannten Verbindungen erlaubt deren Strukturzuordnung und die Untersuchung der thermischen Gleichgewichte. Die cis-cis-Isomeren sind in Benzollösung energetisch gegenüber den trans-trans-Isomeren stark bevorzugt, welche bei den Meßtemperaturen von 100° und 150° nur zu 10 bis 15% im Gleichgewicht vertreten sind.
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  • 78
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Messungen der Optischen Rotationsdispersion und des Zirkulardichroismus von N-Phthalyl-aminen beweisen die Existenz von mindestens einer optischaktiven Absorptionsbande im Bereich oberhalb von 300 mμ, die im UV-Spektrum nicht erkennbar ist. Aus dem Vorzeichen der zugehörigen Cotton-Effekt-Kurve kann die absolute Konfiguration bestimmt werden: N-Phthalyl-Derivate optisch-aktiver Amine der (R)-Reihe zeigen einen negativen Cotton-Effekt, solche der (S)-Reihe einen positiven. Entsprechende Messungen an N-Phthalyl-Derivaten von α-Aminosäuren führten zum Nachweis von mindestens zwei optischaktiven Absorptionsbanden, die wiederum im UV-Spektrum nicht erkennbar sind. Die vorliegende Untersuchung stellt ein weiteres Beispiel dar für die Anwendung der Optischen Rotationsdispersion und besonders des Zirkulardichroismus zur Ermittlung verdeckter Absorptionsbanden.
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 566-574 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei Versuchen, Cyanformaldehyd herzustellen, wurden bei Raumtemperatur nur Cyanwasserstoff und Kohlenmonoxyd bzw. Ameisensäure erhalten. Dagegen konnten das Oxim und Phenylhydrazon des Cyanformaldehyds, beide in syn- und anti- Form, dargestellt werden. Das Cyanformaldoxim ist extrem unbeständig gegen Basen, die den exothermen Zerfall in Dicyan und Wasser katalysieren. Das Oxim und Phenylhydrazon sowie geeignete Derivate konnten nicht zu Abkömmlingen des s-Triazin-trialdehyds trimerisiert werden.
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 588-597 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Für die im Teak aufgefundenen Verbindungen Tectol (C30H26O4, I) und Dehydrotectol (C30H24O4, V) konnte die Konstitution durch Abbau, Reaktion mit Acetylendicarbonsäure-dimethylester, Überführung ineinander sowie durch die Synthese des Tetrahydrotectols (IX), Tectols und Dehydrotectols festgelegt werden. V dürfte das erste in der Natur aufgefundene tieffarbige Dehydrodinaphthol sein. Da es in festem Zustande ein schwaches ESR-Signal gibt, liegt es wohl teilweise als Radikal XIII vor. Ein Cyclisierungsprodukt X aus Tectol und andere Verbindungen aus Teak werden beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 709-714 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird über die Spaltung der Schwefel-Stickstoff-Bindung der Verbindungen CH3SNR2 (R = (CH3, C2H5), [(CH3)2N]2SO durch Borchloride berichtet.
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 725-732 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oson-1-hydrazone und Osazone, die nur asymmetrisch disubstituierte Hydrazinreste enthalten, reagieren mit Hydroxylamin unter Bildung von Oson-1-hydrazon-2-oximen. Mit primären Hydrazinen lassen sich daraus Mischosazone herstellen. Vergleichend wird über entsprechende Derivate des Methylglyoxals berichtet.
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  • 83
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Einige aliphatische Diazoverbindungen - hauptsächlich aus der Reihe des Diazocyclopentadiens und der Bis-alkyl- bzw. Bis-arylsulfon-diazomethane - mit zum Teil recht hoher Säurestabilität werden dargestellt. Die der NN-Schwingung zuzuordnende Infrarotabsorption im Wellenzahlenbereich um 21OO/cm verschiebt sich mit zunehmender Säurestabilität nach höheren Frequenzen.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 741-746 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylphosphin sowie Phenyl-biphenylen-phosphin wurden durch Umsetzung mit Phenylazid und anschließend Methylbromid in die zugehörigen Iminiumbromide I und III übergeführt, die sich bei Einwirkung von Lithiumarylen zu pentaarylierten Phosphoranen abwandeln ließen. Nach diesem neuen Verfahren konnten außer Pentaphenylphosphoran die analogen Verbindungen IV, V und XI präpariert werden.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 801-808 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Drei Vertreter der im Tribus Anthemideae L. Weit verbreiteten Enolätherspiroketale werden synthetisiert. Die als Recemate erhaltenen Enoläther stimmen IR-spektroskopische mit den Naturstoffen überein. Eine weitere Verbindung, die erstmals von N. A. SÖRENSEN isoliert worden ist, wird in ihrer Struktur durch Synthese gesichert.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 721-724 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkaliphosphide vom Typ MePHR (R = C6H5, c-C6H11; Me = Na, K) reagieren mit Kohlendioxid bzw. Chlorameisensäure-äthylester unter Metall-Wasserstoff- Austausch über die Zwischenprodukte MeP(R)CO2 Me bzw. MeP(R)CO2C2H5 zu prim. Phosphinen und Organophosphin-P.P-bis-carboxylaten bzw. -[carbonsäure-äthylestern] RP(CO2Me)2 bzw. RP(CO2C bzw. RP(CO2 C2H5)2. - Im Gegensatz zu den nicht existenten Säuren RP(CO2H)2 (Zerfall in CO2 und RPH2) sind die Ester RP(CO2C2H5)2 relativ luftbeständige, destillierbare Flüssigkeiten.
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  • 87
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 842-848 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Umsetzung des Pseudoalkalisilanolats Heptamethylstibinosiloxan mit Tris-trimethylsiloxy-aluminium, -gallium und -eisen entstehen spontan und quantitativ wohlkristallisierte, neuartige Tetramethylstibonium-tetrakis- trimethylsiloxy-metallate des Typs [(CH3)4Sb]⊕{Al, Ga, Fe[OSi(CH3)3]4}⊖. Physikalische und chemische Eigenschaften sowie IR- und NMR-spektroskopische Daten beweisen für diese Verbindungen eine ionische Struktur aus tetraedrischen Tetramethylstibonium-Kationen und Tetrakis-trimethylsiloxy-metallat-Anionen, die inzwischen auch durch Röntgenstrukturanalyse gesichert werden konnte. Die Struktur- und Bindungsverhältnisse werden an Hand der vorliegenden spektroskopischen und kristallographischen Daten diskutiert.
    Additional Material: 6 Tab.
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  • 88
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 863-871 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aliphatische bzw. alicyclische α.β-und β-γ-ungesättigte Carbonsäureester liefern in Gegenwart von Co2(CO)8 als Katalysator mit Synthesegas bei 200-250β gesättigte mono- bzw. bicyclische Lactone. Bei längerkettigen α.β-ungesättigten Estern werden infolge Isomerisierung während der Reaktion neben γ- auch δ-Lactone erhalten.
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  • 89
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 884-890 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Umsetzung von Methylazid mit Antimon(V)-chlorid in Methylenchlorid wurde ein Addukt der Zusammensetzung H3CN3:SbCl5 erhalten, das unter der Einwirkung von trockenem Chlorwasserstoff in Methylenchlorid in ein stabiles Methylenimmonium-hexachloroantimonat(V) (V) überging. Bei Ersatz von Chlorwasserstoff durch Deuteriumchlorid entstand N-monodeuteriertes Methylenimmonium-hexachloroantimonat(V). Die IR-Spektren aller dargestellten Verbindungen wurden aufgenommen und zugeordnet.
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  • 90
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 909-920 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lignin nach Björkman wurde mit Methanol/Chlorwasserstoff und mit wäßrigem Schwefeldioxyd behandelt. Dabei vermehren sich die titrimetrisch ermittelten Phenolgruppen. Entsprechende Versuche wurden ausgeführt mit Modellsubstanzen und den als Zwischenprodukte der Ligninbildung erkannten β-γ-Diaryläthern des Guajacylglycerins. Etwa jede achte bis zehnte Einheit des Coniferenlignins besteht aus Guajacylglycerin, das am γ-Hydroxyl mit Arylgruppen veräthert ist. Die γ-Aryläther entstehen bei der Addition von Phenolen an Chinonmethide und bei der Polymerisation der Chinonmethide.
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  • 91
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 934-945 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Reaktion von Oxalychlorid mit silyliertem 4.5-Diamino-uracil (I) führt unter Ringschluß zu 2.4.6.7-Tetrakis-trimethylsiloxy-pteridin (II); silylierte Aminopyrimidine ergeben unter diesen Bedingungen Purin-Derivate. Die besonders leicht alkylierbare Tetrakis-triäthylsilyl-harnsäure VI liefert bei Einwirkung von Dimethyl-bzw. Diäthylsulfat. oder Methyljodid fast quantitativ z. T. sonst nur schwer zugängliche Derivate wie 1.7.9-Trimethyl- (VIIa), 1.7.9-Triäthyl-(VIIb), 1.3.7.9-Tetramethyl- (VIIc) und 1-Methyl-harnsäure (XIII). Ebenso läßt sich silylierte Harnsäure VI gut in 3-Stellung glykosidieren. So konnten erstmals Harnsäure VI gut in 3-Stellung glykosidieren. So konnten erstmals Harnsäure-3-glucosid (XIXf), -3-ribopyranosid (XIXd) und -3-ribofuranosid (XIXe) erhalten werden. Letzteres ist mit dem in der Natur vorkommenden Ribosid identisch.
    Additional Material: 6 Tab.
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  • 92
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 989-993 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Hydrazinhydrat bzw. Derivaten des Hydrazins und Isothiocyanato-essigsäure-äthylester werden Thiosemicarbazino-(4)-essigester dargestellt. Analog wie bei den Oligo-„[semicarbazino-[4]-essigsäuren]“ wird eine „Di-[thiosemicarbazino-(4)-essigsäure]“-Kette aufgebautExaktere Bezeichnungen wären hier zu unhandlich, vgl. 46. Mitteil., vorstehend. Es wird über einige Eigenschaften und Reaktionen der neuen Verbindungen berichtet. Außerdem werden IR-Spektren wiedergegeben und diskutiert.
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  • 93
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 983-988 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Cbo(Tosyl)-Hydrazinen und verschiedenen α-Isocyanato-fettsäure-äthylester werden α-[1-Acyl-semicarbazino-(4)]-fettsäure-äthylestern dargestellt. [1-Acyl-semicarbazino-(4)]-essigester wird in das Hydrazid übergeführt und erneut mit Isocyanato-essigester umgesetzt, wobei ein Stoff mit zwei aneinandergeknüpften Semicarbazino-(4)-acetyl-Resten erhalten wird. Diese Kettenverlängerung wird bis zum Acyl-„tetra-[semicarbazino-(4)-essigester]“Für die Bezeichnung der neuen Verbindungen werden hier häufig verschiedene Vorschläge gemacht. Exakte Namen werden für die einfacheren Verbindungen oder Verbindungstypen meistens nur einmal wiedergegeben, während bei einer wiederholten Erwähnung Vereinfachungen getroffen werden. Für die höhermolekularen stoffe muß wegen der Kompliziertheit auf eine korrekte Bezeichnung (ähnlich wie bei den Peptiden) ganz verzichtet werden) fortgeführt. Es werden einige Eigenschaften und IR-Spektren der auch als „Azapeptide“ aufzufassenden neuartigen Verbindungen diskutiert.
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  • 94
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Pterine, die bei der Kondensation von 2.4.5.-Triamino-6-hydroxy-pyrimidin (I) mit Glucose bzw. Ribose mit oder ohne Hydrazinzusatz entstehen, wurden papierchromatographisch getrennt und weitgehend identifiziert. Es sind neben den 8/9-isomeren Tetra- und Trihydroxy-butyl-pterinen bzw. den Tri- und Dihydroxy-propyl-pterinen vor allem 8-Polyhydroxyalkyl-9-methyl-pterine und 9-Methyl-pterin.  -  Der komplizierte Reaktionsablauf und die Vielfalt der Reaktionsprodukte wird gedeutet.  -  Unter speziellen Bedingungen lassen sich vier Pterinderivate ohne schwierige Reinigungsoperationen isomerenfrei darstellen: 1. 9-[Tetrahydroxy-butyl]-pterin, 2. 8-[Tetrahydroxy-butyl]-pterin, 3. 8-[1′.2′-Dihydroxy-äthyl]-9-methyl-pterin und 4. 2-Acetamino-4-hydroxy-9-[3′.4′-diacetoxy-buten-(1′)-yl]-pteridin.  -  Bei der katalytischen Hydrierung von 9-Polyhydroxyalkyl-pterinen tritt eine stufenweise Eliminierung der Hydroxylgruppen der Seitenkette ein.
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  • 95
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1057-1068 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das von MALKIN und NIERENSTEIN durch Einwirken von Zink/Acetanhydrid erhaltene vermeintliche Quercetylen ist kein Dimerisierungsprodukt, sondern Pentaacetoxy-flaven-(3). Ausgehend von Flavonolen über die Thioflavonole sind Quercetylen-decamethyläther und andere Biflavenylidene-(4) zugänglich, deren Struktur diskutiert wird.  -  Mit Ausnahme des Quercetylenäthers zeigen die Biflavenylidene Piezochromie und Piezomagnetismus.
    Additional Material: 7 Tab.
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  • 96
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1085-1095 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus den Cycloadditionen der Nitrilimine an 14 Azomethine gehen 4.5-Dihydro-1.2.4-triazole in guter Ausbeute hervor. Diphenylnitrilimin lagert sich an die CN- und die CO-Doppelbindung der Arylisocyanate an, wobei 1.3-Diphenyl-4-aryl-1.2.4-triazolone-(5) und 2.4-Diphenyl-1.3.4-oxadiazolon-(5)-arylimide entstehen.
    Additional Material: 2 Tab.
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  • 97
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1115-1117 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Trichlorsilylgruppen enthaltenden Chlormethanen wurde mit Chlorwasserstoff in Gegenwart geringer Mengen Dimethylanilin eine dieser Gruppen als Siliciumtetrachlorid abgespalten: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Cl}_{\rm n} {\rm C}({\rm SiCl}_3)_{4 - {\rm n}} \, + \,{\rm HCL} \to \,{\rm SiCl}_4 \, + \,{\rm Cl}_{\rm n} {\rm CH}({\rm SiCl}_3)_{3 - {\rm n}} $$\end{document} Von den Entsprechenden methanen ging nur Tris-trichlorsilyl-methan diese Reaktionen ein. Das beschriebene Verfahren kann zur Aufklärung der Struktur dieser und ähnlicher Verbindungen dienen.
    Additional Material: 2 Tab.
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  • 98
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1147-1149 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Natriumcyanid mit 57.3% 13C wird über sechs Stufen in 25.6-proz. Ausbeute 1.4-13C-markiertes p-Benzochinon dargestellt.
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  • 99
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1369-1372 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wurden die kernmagnetischen 19F-Resonanzspektren flüssiger Mischungen aus SSF2 und FSSF untersucht, welche aus Kaliumfluorid und Dischwefel-dichlorid sowie Silberfluorid und Schwefel hergestellt worden waren. Die gefundenen chemischen Verschiebungen betragen, bezogen auf CFCl3, für SSF2 -79.5 ppm und für FSSF +122.5 ppm. Das Verfahren zur Gewinnung reinen Difluordisulfans, FSSF, aus Silberfluorid und Schwefel wird angegeben.
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  • 100
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    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1207-1213 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das partiell durch N-tert.-Butyloxycarbonylgruppen (Abk. BOC) und tert.-Butylreste (Abk. t. Bu) geschützte β 1-23-Corticotropin-tyrosin23-amid wird nach dem Schema 10 + 13 mittels der Nitrophenylester- und der Carbodiimid-methode synthetisiert und durch Chromatographie an Sephadex®-G 25 angereichert. Das durch Abspalten der Schutzgruppen mit Trifluoressigsäure erhaltene Tricosapeptidamid-trifluoracetat wird durch Chromatographie an Carboxy-methylcellulose und durch kontinuierliche Hochspannungselektrophorese gereinigt. Die chromatographisch und elektrophoretisch einheitliche Verbindung zeigt im Sayers-Test an der Ratte bei intravenöser Applikation volle ACTH- Aktivität.
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