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  • Articles  (41)
  • Inorganic Chemistry  (33)
  • Physical Chemistry
  • 1975-1979  (41)
  • 1979  (41)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 11 (1979), S. 175-185 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relaxation rates for O2(1Σg+) by nonradiative pathways have been determined using the fast-flow technique. O2(1Σg+) is formed from O2(1Δg) by an energy pooling process. O2(1Δg) is generated by passing purified oxygen through a microwave discharge. Oxygen atoms are removed by distilling mercury vapor through the discharge zone. It has been observed that the wall loss rate for O2(1Σg+) decreases with increasing pressure of oxygen and thus appears to be diffusion controlled. Quenching rate constants for O2, N2, and He have been determined and found to be (1.5 ± 0.1) × 104, (1.0 ± 0.05) × 106 and (1.2 ± 0.1) × 105 l./mol·sec, respectively.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 11 (1979), S. 357-374 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rate, equilibrium, and thermodynamic data for reaction (1) of 2,6-diphenyl-4R-phenoxyl radicals, where R==OCH3 (I), Ph (II), OC2H5 (III), O-n-C18H37 (IV), and 2,6-dicyclohexyl-4-phenylphenoxyl radical (V), in various solvents are obtained. The k1 values of radicals I to V are within (5.5 ± 1.0) × 107-(1.4 ± 0.3) × 109M-1·sec-1 in propanol. The solvent effect on k1 for radicals I and II was studied. The dimerization of radical I is diffusion-controlled in all solvent studies. The dimerization of radical II is viscosity-dependent but not diffusion-controlled. Plots of k1 against ET have a V shape. Specific solvent-solute interactions are seeming to be responsible for numerical k1 values of radicals I and II. The solvent effect is more pronounced for “slow” dimerization of radicals II than for “fast” dimerization of radicals I. The minimum k1 values correspond to pyridine and chloroform. The reaction (1) rate strongly depends upon the composition of a chloroform (S)-cosolvent binary mixture. Besides reaction (1) the following reactions proceed in binary mixture: \documentclass{article}\pagestyle{empty}\begin{document}$$ K_{14} = 0.18 \pm 0.05M^{ - 1},k_{15} = (2.0 \pm 1.0) \times 10^8 M^{ - 1} \cdot \sec ^{ - 1} $$\end{document} (radical I, S-CCL4 mixture) \documentclass{article}\pagestyle{empty}\begin{document}$$ K_{14} = 0.9 \pm 0.2M^{ - 1},k_{15} = (1.2 \pm 0.5) \times 10^7 M^{ - 1} \cdot \sec ^{ - 1} $$\end{document}(radical II, S-C6H14 mixture) \documentclass{article}\pagestyle{empty}\begin{document}$$ K_{14} = 0.45 \pm 0.10M^{ - 1},k_{15} = (9.0 \pm 2.0) \times 10^6 M^{ - 1} \cdot \sec ^{ - 1} $$\end{document}(radical II, S-CCL4 mixture)In all cases k16 ≪ k15. Factors influencing dimerization rates in strongly nonideal mixtures CH3OH-CCL4 and CH3OH-CHCl3 are discussed.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 449 (1979), S. 25-40 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vanadiumoxid Monoschichtkatalysatoren. I. Darstellung, Charakterisierung und thermische StabilitätDurch Chemisorption von Vanadat(V)-Anionen aus wäßrigen Lösungen, bzw. Chemisorption von gasförmigem V2O3(OH)4 wurden Vanadinoxidkatalysatoren des Monoschichttyps dargestellt. Mit Al2O3, Cr2O3, TiO2, CeO2, und ZrO2 als Trägeroxiden, können Katalysatoren mit einer ungefähr vollständigen monomolekularen Schicht von Vanadin(V)-Oxid auf den Trägeroxiden dargestellt werden, falls die Temperatur nicht zu hoch ist. Zweiwertige Metalloxide wie z. B. CdO und ZnO können schon bei niedriger Temperatur dreidimensionale Oberflächenvanadate bilden.Die thermische Stabilität eines Monoschichtkatalysators ist verbunden mit dem Parameter z/a: dem Quotient der Ladung des Trägerkations und der Summe der Ionenradien von Trägerkation und Oxidanion. Monoschichten werden thermisch nur stabil sein, falls z/a nicht zu groß (aggregierter Katalysator) und nicht zu klein (Bildung einer ternären Verbindung) ist.
    Notes: Vanadium oxide catalysts of the monolayer type have been prepared by means of chemisorption of vanadate(V)-anions from aqueous solutions and by chemisorption of gaseous V2O3(OH)4. Using Al2O3, Cr2O3, TiO2, CeO2 and ZrO2, catalysts with an approximately complete monomolecular layer of vanadium(V) oxide on the carrier oxides can be prepared, if temperature is not too high. Divalent metal oxides like CdO and ZnO may already form threedimensional surface vanadates at moderate temperature.The thermal stability of a monolayer catalyst is related to the parameter z/a, i. e. the ratio of the carrier cation charge to the sum of ionic radii of carrier cation and oxide anion. Thus, monolayer catalysts will be thermally stable only under the condition that z/a is not too high (aggregated catalyst) nor too small (ternary compound formation).
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 457 (1979), S. 238-240 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung und Eigenschaften von Hg5TeCl8In schwefelsaurer Lösung reagiert HgTe mit überschüssigen Quecksilber(II)-Ionen unter Bildung löslicher kationischer mehrkerniger Komplexe. Die Verbindungen Hg5TeCl8 und Hg4Te(SO4)3 werden dargestellt und beschrieben.
    Notes: Telluride ion forms polynuclear soluble cationic complexes with excess Hg(II) in sulphuric acid media. Compounds Hg5TeCl8 and Hg4Te(SO4)3 were prepared and characterised.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 456 (1979), S. 16-28 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About the Reactivity of Na [Mn2(CO)9CN]The reactions of Na[Mn2(CO)9CN] with Et3OBF4, Me3SiCl, Me3GeCl, Me3SnCl, PPh2Cl, or MeCOCl lead to the dinuclear monoisonitrile complexes Mn2(CO)9CNR (R = Et, SiMe3, GeMe3, SnMe3, PPh2, COMe) which are characterized by their mass, vibrational, and n.m.r. spectra. However the solvates Na[Mn2(CO)9CN] · CH3COCH2Cl and Na[Mn2(CO)9CN] · NCCH2Cl are formed with CH3COCH2Cl and NCCH2Cl. Similar adducts are obtained with the Lewis bases CH3COCH3, NCCH3, and O(C2H5)2.
    Notes: Bei den Reaktionen von Na[Mn2(CO)9CN] mit Et3OBF4, Me3SiCl, Me3GeCl, Me3SnCl, PPh2Cl bzw. MeCOCl, werden die zweikernigen Monoisonitril-Komplexe Mn2(CO)9CNR (R = Et, SiMe3, GeMe3, SnMe3, PPh2, COMe) gebildet, die anhand ihrer Massen-, Schwingungs- und NMR-Spektren charakterisiert werden. Dagegen führen die entsprechenden Umsetzungen mit CH3COCH2Cl bzw. NCCH2Cl zu den Solvaten Na[Mn2(CO)9CN] · CH3COCH2Cl und Na[Mn2(CO)9CN] · NCCH2Cl. Eine ähnliche Adduktbildung erfolgt auch mit den Lewisbasen CH3COCH3, NCCH3 und O(C2H5)2.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 936-949 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Silyl and N-Germylpyridinyl Radicals, and Their Stabilization ReactionsPyridines, functionally substituted in 2-, 3-, or 4-position, give N-silylpyridinyls (3, 7, 11, 16, 19, 23) upon reaction with (Me3Si)2Hg, and further on mostly N,ω-bis(silyl) derivatives (5), tetrahydro-4,4′-or -2,2′-bipyridines (9, 17, 20, 21, 24, 25), depending on mesomeric and steric conditions. 2- and 3-acylpyridines yield O-silylated hydropyridoins (27, 30), 2-cyanopyridine forms a persistent pyridinyl (29). N-Germylpyridinyls (32-34) are generated for the first time. With (Me3Ge)2Hg, they are formed, however, only in the case of substituted pyridines of low electron density or strong mesomeric stabilization of the radicals. Several N ω-bis(germyl)-dihydropyridines (36, 37) rearrange, in part even at -30°C, with a surprising N, C-migration of a germyl residue, restoring the aromatic system, giving 35, 39. ESR data are given for most of the generated radicals.
    Notes: In 2-, 3- oder 4-Stellung funktionell substituierte Pyridine geben mit (Me3Si)2Hg N-Silylpyridinyle (3, 7, 11, 16, 19, 23), die je nach Mesomeriestabilisierung und sterischer Hinderung meistens zu N,ω-Bis(silyl)-Derivaten (5) oder zu Tetrahydro-4,4′- bzw. -2,2′-bipyridinen (9, 17, 20, 21, 24, 25) weiterreagieren. 2- und 3-Acylpyridine ergeben O-silylierte Hydropyridoine (27, 30), 2-Cyanpyridin ein kinetisch stabiles Pyridinyl (29). N-Germylpyridinyle (32-34) werden erstmals erhalten. Sie entstehen mit (Me3Ge)2Hg nur im Falle elektronenarmer substituierter Pyridine bzw. starker Mesomeriestabilisierung der Radikale. Bei N,ω-Bis(germyl)dihydropyridinen (36, 37) wurde, z. T. schon bei -30°C, eine überraschende N,C-Wanderung eines Germylrestes unter Rückbildung des aromatischen Systems zu 35, 39 gefunden. Für die meisten der erhaltenen Radikale werden die ESR-Daten angegeben.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 950-956 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Mechanism of the Photolytic Reaction of Pyridine with Bis(trimethylsilyl)mercury, a Contribution to the Photochemistry with Metal AlkylsThe photolytic generation of N-(trimethylsilyl)pyridinyls 2 or. resp., their 4,4′-dimers from pyridine or its alkyl derivatives and bis(trimethylsilyl)mercury (1) involves surprisingly no free silyl radicals, but passes a long-lived, photoexcited, polar state 1a of the molecule 1. The latter is described more closely. It is complexed stepwise by two molecules of pyridine, and only in the last step free radicals are formed. The possibly more general importance of these findings for photolytic reactions with metal alkyls is pointed out.
    Notes: Die photolytische Bildung von W-(Trimethylsilyl)pyridinylen 2 bzw. ihren 4.4′-Dimeren. aus Pyridin bzw. seinen Alkylverbindungen und Bis(trimethylsilyl)quecksilber (1) verläuft überraschenderweise nicht über freie Silyl-Radikale, sondern über einen längerlebigen, photoangeregten, polaren Zustand la des Moleküls 1, über den nähere Aussagen gemacht werden. Er wird schrittweise durch zwei Moleküle Pyridin komplexiert, worauf erst im letzten Schritt freie Radikale entstehen. Auf die mögliche Bedeutung der Befunde für andere photolytische Reaktionen mit Metallalkylen wird hingewiesen.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1348-1358 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electrophilic Aromatic Substitution Reactions with Protonated 1,3-Diazines, II. Preparation and Properties of 4-Aryl-substituted 3,4-Dihydroquinazoline DerivativesIn the presence of trifluoroacetic acid, quinazoline and 2-methylquinazoline react with a great variety of aromatic compounds to form 4-aryl-substituted 3,4-dihydroquinazolinium salts, e. g. 2, 3. From those, the dihydro bases 4 can be obtained which are readily oxidized to 4-aryl-substituted quinazolines 5, 6. Highly reactive compounds like indole are treated in formic acid or acetic acid, for better results. Also, some CH-acidic compounds react with quinazoline in trifluoroacetic acid.
    Notes: Bei Gegenwart von Trifluoressigsäure (TFE) reagieren Chinazolin und 2-Methylchinazolin mit einem weiten Spektrum aromatischer Verbindungen zu stabilen 4-arylsubstituierten 3,4-Dihydro-chinazoliniumsalzen, z. B. 2, 3, aus denen sich die zugrunde liegende Dihydrobase 4 erhalten läßt, die ihrerseits zu 4-arylsubstituierten Chinazolinen 5, 6 oxidiert werden kann. Im Fall besonders reaktiver Aromaten (z. B. Indol) läßt sich TFE vorteilhaft durch Eisessig oder Ameisensäure ersetzen. Auch eine Reihe CH-acider Verbindungen reagiert in TFE mit Chinazolin.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1-15 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electrophilic Aromatic Substitution Reactions with Protonated 1,3-Diazines, I. Preparation and Properties of 4-Aryl-substituted 3,4-Dihydropyrimidine DerivativesIn the presence of trifluoroacetic acid, pyrimidine and 5-methylpyrimidine react with active aromatic compounds to form stable 4-aryl-substituted 3,4-dihydropyrimidinium salts, e.g. 1, 2, 6. From these, the dihydro bases 7 or 8 can be obtained which are readily oxidized to 4-aryl-substituted pyrimidines 9. 2- and/or 4-substituted pyrimidines as well as 2-amino- and 2-mercaptopyrimidines react with phenols to form benz[g][1,3,5]oxadiazocines 3 and 10. The mechanism of this novel reaction is apparently best described as an aromatic electrophilic substitution by the protonated pyrimidine derivative. The observed reactivity of different diazines is in accordance with frontier orbital arguments, using HMO-coefficients.
    Notes: Bei Gegenwart von Trifluoressigsäure reagieren Pyrimidin und 5-Methylpyrimidin mit aktiven aromatischen Verbindungen zu stabilen 4-arylsubstituierten 3,4-Dihydropyrimidinium-Salzen, z. B. 1, 2, 6, aus denen sich die zugrunde liegende Dihydrobase 7 bzw. 8 erhalten läßt, die ihrerseits leicht zu 4-arylsubstituierten Pyrimidinen 9 oxidiert werden kann. 2- und/oder 4-substituierte Pyrimidine sowie 2-Amino- und 2-Mercaptopyrimidine bilden mit Phenolen Benz[g][1,3,5]oxadiazocine der (Konstitution 3a - f und 10. Als Reaktionsmechanismus wird eine elektrophile Substitutionsreaktion durch das protonierte Pyrimidinderivat vorgeschlagen. Die beobachtete Reaktivität der verschiedenen Diazine steht im Einklang mit dem Grenzorbital-Modell auf der Basis der HMO-Koeffizienten.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 11 (1979), S. 1055-1069 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Methylallyl, 1,1-dimethylallyl, 1,2-dimethylallyl, 1,3-dimethylallyl, 1,1,2-trimethylallyl, and 1-ethylallyl radicals have been generated in the gas phase at 20 ± 1°C by addition of H atoms, formed by Hg(63P1) photosensitization of H2, to appropriate dienes. Their combination reactions with ethyl radicals have been studied and the relative reactivities of the reaction centers in each allylic radical determined. Similar measurements have been made for some combination reactions of n-propyl, i-propyl, and t-butyl with 1-methylallyl and 1,1,2-trimethylallyl radicals. The more substituted reaction centers are found to be the less reactive. In addition the self-combination and disproportionation of 1-methylallyl radicals has been investigated, as has cross disproportionation of each allylic radical with ethyl. The results establish a general pattern of reactivity for these radicals, which is interpreted primarily in terms of the effects of steric interaction during reaction.
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