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  • 1
    Electronic Resource
    Electronic Resource
    Type B Semiconductor Photocatalysis: The Synthesis of Homoallyl Amines by Cadmium Sulfide-Catalyzed Linear Photoaddition of Olefins and Enol/allyl Ethers to N-Phenylbenzophenone ImineHeterogeneous Photocatalysis, part XVI. Part XV: W. Schindler, H. Kisch, J. Photochem. Photobiol. A: Chem., 1997, 103, 257. (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1638-1645 
    Details
    ISSN: 0947-6539
    Keywords: cadmium sulfide ; catalysis ; photochemistry ; semiconductors ; unsaturated amines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homoallyl amines were synthesized by visible-light irradiation of CdS powder in the presence of N-phenylbenzophenone imine and cyclohexene, 2,3-dihydrofuran, 2,5-dihydrofuran, 3,4-dihydropyran, 2-pentene, cyclopentene, 1-methylcyclohexene, or α-pinene. The structures of the products from the last three olefins were determined by single-crystal X-ray analysis to prove that C-alkylation of the imine had occurred. Thus, the reaction is formally an insertion of the imine into an allylic C-H bond of the olefin. It is proposed that a photogenerated electron-hole pair reduces the imine to an α-aminodiphenylmethyl radical and oxidizes the olefin with concomitant deprotonation to the corresponding allyl radical. Heterocoupling of these intermediates affords the final addition product. The overall reaction is therefore classified as type B semiconductor photocatalysis. The presence of acetic acid accelerates the reaction by rendering the reduction potential of the imine more positive. In the series 2,5-dihydrofuran/cyclopentene/3,4-dihydropyran, the decrease in apparent quantum yield with increasing driving force of olefin oxidation points to a significant contribution of secondary back electron transfer.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970031013
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  • 2
    Electronic Resource
    Electronic Resource
    Semiconductor-Catalysed Photoaddition of Olefins and Enol Ethers to 1,2-Diazenes: A New Route to AllylhydrazinesHeterogeneous Photocatalysis XIII. Part XII: H. Kisch. J. Prakt. Chem. 1994, 336, 635Dedicated to Professor Hans-Dieter Scharf on the occasion of his 65th birthday (1995)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 1 (1995), S. 441-448 
    Details
    ISSN: 0947-6539
    Keywords: allylhydrazines ; cadmium compounds ; catalysis ; photochemistry ; zinc compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Suspensions of zinc or cadmium sulfide powders in a protic solvent catalyse the linear addition of enol ethers and olefins to 1,2-diaryl- and 1-aryl-2-alkyl-1,2-diazenes, producing allylhydrazine derivatives. Relative quantum yields decrease sharply when the 1,2-diazene is more difficult to reduce, while their relationship to the oxidation potential of the enol ether/olefin is complicated. Reduction to 1,2-diarylhydrazine and concomitant dehydrodimerization of the enol ether occurs as a side reaction. It is favoured by increasing light intensity and becomes the major reaction path when platinized (5 mol%) photocatalysts are employed. It is proposed that the photogenerated electron-hole pair in a proton-coupled electron transfer reduces the diazene to a hydrazyl radical and oxidizes the olefin/enol ether to a radical cation. The allylic radical obtained from the latter by deprotonation then undergoes C—N coupling with the hydrazyl radical to afford the allylhydrazine. Diarylhydrazine formation occurs by disproportionation of the hydrazyl radical or by a successive proton-coupled reduction. Thus photoaddition can be classified as a 1 e-/1 h+ process while 2e-/2h+ are necessary for the reduction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19950010709
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  • 3
    Electronic Resource
    Electronic Resource
    Charge-Transfer-Komplexe von Metalldithiolenen, IV. Viologene als redoxaktive Akzeptoren - Synthese und elektrische Leitfähigkeit (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 1023-1030 
    Details
    ISSN: 0009-2940
    Keywords: Metal dithiolenes ; Viologens ; Charge-transfer complexes ; Electrical conductivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Charge-Transfer Complexes of Metal Dithiolenes, IV. - Viologens as Redoxactive Acceptors - Synthesis and Electrical ConductivityTitle compounds of the type [G]n+m [ML2]m-n are prepared from viologens or related bipyridylium halides GXn and mono- or dianionic metal dithiolenes [ML2]m- (M = Ni, Pd, Pt; L = a substituted or unsubstituted 1,2-ethenedithiolate; m = 1,2). IR and UV-VIS spectra essentially exhibit absorption bands of the components whereas all dianionic complexes additionally show ion pair charge-transfer bands in the long wavelength region (850-1250 nm). All complexes show semiconducting behaviour with electrical conductivities ranging from 7.5 · 10-3 〈 1 · 10-10 S/cm (measured as compacted pellets at 293 K) depending on the nature of the ligand, metal, anion charge, and the cation size. The conductivity of monoanionic dithiolene complexes is influenced by the steric properties of the viologen cations while charge-transfer interaction seems to be more important in the case of dianionic dithiolenes.
    Notes: Die Titelverbindungen vom Typ [G]n+m [ML2]m-n werden aus Viologenen oder verwandten Bipyridyliumhalogeniden GXn und mono- oder dianionischen Metalldithiolenen [ML2]m- (M = Ni, Pd, Pt; L = ein substituiertes oder unsubstituiertes 1,2-Ethendithiolat; m = 1,2) synthetisiert. IR- und UV-VIS-Spektren spiegeln im wesentlichen das Absorptionsverhalten der Komponenten wider, darüber hinaus zeigen alle dianionischen Komplexe Ionenpaar-Charge-Transfer-Banden im langwelligen Spektralbereich (800-1250 nm). Alle Verbindungen besitzen Halbleiter-eigenschaften. Die bei 293 K an Pulverpreßlingen gemessenen elektrischen Leitfähigkeiten variieren in Abhängigkeit von Ligand, Zentralmetall, Anionenladung und Kationengröße von 7.5 · 10-3 bis 〈 1 · 10-10 S/cm. Während die Leitfähigkeitseigenschaften der monoanionischen Dithiolenkomplexe weitgehend durch den sterischen Einfluß der Viologen-Kationen bestimmt werden, scheint im Falle der dianionischen Dithiolenkomplexe die Charge-Transfer-Wechselwirkung ausschlaggebend zu sein.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220602
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  • 4
    Electronic Resource
    Electronic Resource
    Charge-Transfer Complexes of Metal Dithiolenes, XXIIPart XXI: Ref.. Bis(maleonitriledithiolato)oxomolybdate(IV) - Bipyridinium Ion PairsDedicated to Professor Herrmann Rau on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 33-37 
    Details
    ISSN: 0009-2940
    Keywords: Oxomolybdenum dithiolenes ; Viologens ; Ion pair charge-transfer ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxomolybdenum complex (NBu4)2[MoO(mnt)2] (mnt2- = maleonitriledithiolate) 2 was characterized by X-ray structural analysis. By metathetic reaction with bipyridinium salts AX2 ion pair charge-transfer complexes of composition {A2+[MoO(mnt)2]2-} were isolated. Although a plot of the energy of the ion pair charge-transfer band vs. the driving force of electron transfer from the dianion to the dication afforded a straight line, the slope of 0.45 suggests significant deviations from the Hush-Marcus model. When bis(2-hy-droxyethyl)viologen is the acceptor, in addition to the supra-molecular charge-transfer interaction, hydrogen bridges are introduced between the two components as indicated by IR and X-ray diffraction analysis.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290109
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