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1Author    Grazyna Wenska, Stefan PaszycRequires cookie*
 Title    Photolysis of Thiopurines in the Presence of Oxygen +  
 Abstract    Irradiation (A > 290 nm) of 6-thiopurine and some 9-substituted 6-thiopurines in oxygen saturated iertf-butanol leads to hypoxanthine, purine and purine-6-sulfonic acid or their substituted derivatives. Purine and hypoxanthine formation can be sensitized with dyes. The reaction of 6-thiopurine with singlet oxygen has also been performed with purine and hypoxanthine among other products. It seems however that x 02 is not an important intermediate in the photooxygenation. The photoreaction may have some synthetic value. Hypoxanthines (~50%) or purines (35-45%) were obtained depending on the solvent used. 
  Reference    Z. Naturforsch. 36b, 1628—1631 (1981); received June 9 1981 
  Published    1981 
  Keywords    Thiopurines, Photolysis, Photooxygenation, Purine Derivatives 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1628.pdf 
 Identifier    ZNB-1981-36b-1628 
 Volume    36 
2Author    Heinz-Peter Schuchmann, Peter Naderwitz, Clemens Von SonntagRequires cookie*
 Title    Photolysis (A 185 nm) of Liquid Tetrahydropyran  
 Abstract    The main products of the 185 nm photolysis of neat liquid tetrahydropyran are pent-4-en-l-ol (7) (0 = 0.40), 2-(5'-hydroxypentyl)tetrahydropyran (10) (0.21), valeraldehyde (6) (0.13), and pentan-l-ol (8) (0.08). These products are thought to be formed via the bi-radical '0(0112)40112, and/or through intramolecular (6, 7, 8) and intermolecular (10) photoreactions. In the case of 10, the probability of a specific intermolecular photoreaction involving two tetrahydropyran molecules is suggested by the fact that in the photolysis of solutions of tetrahydropyran in cyclohexane and formaldehyde dimethyl acetal products analogous to 10 made up of a tetrahydropyran and a solvent molecule moiety, are not formed. 
  Reference    Z. Naturforsch. 33b, 942—945 (1978); received April 28 1978 
  Published    1978 
  Keywords    Photolysis, Tetrahydropyran, Quantum Yields, Biradical Intermediates, Photodimer 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0942.pdf 
 Identifier    ZNB-1978-33b-0942 
 Volume    33 
3Author    Eva-Maria Strauss, Ralf SteudelRequires cookie*
 Title    Photolyse von elementarem Schwefel (S 6 , S 7 , S 8 , S 10 , S 12 ) in Kohlenstoffdisulfidlösung [1]  
 Abstract    The photochemical decomposition of pure carbondisulfide as well as of solutions of pure S 6 , S 7 , S 8 , S I0 and S 12 , respectively, in CS 2 at 15 °C on irradiation by a high-pressure mercury lamp (200-600 nm) has been studied by quantitative HPLC analysis of the soluble products. In all cases mixtures of sulfur homocycles S" (n = 5,6, ...) are formed with S 8 , S 7 and S 6 being the dominating species, but traces of S 5 , S 9 , S 10 and S 12 have also been observed in most cases. S 5 has been identified for the first time; it is formed in particular in the photolysis of S 7 in CS 2 . All irradiated sulfur solutions reach more or less the same photostationary equilibrium, but the decomposition of CS 2 increases linearly with time and its effects are superimposed on the S" interconversion reactions. 
  Reference    Z. Naturforsch. 42b, 682—690 (1987); eingegangen am 20. Februar 1987 
  Published    1987 
  Keywords    Elemental Sulfur, Photolysis, HPLC, Carbondisulfide, Sulfur Homocycles 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-0682.pdf 
 Identifier    ZNB-1987-42b-0682 
 Volume    42 
4Author    Hansjörg GrützmRequires cookie*
 Title    Spaltung der Ylid-Bindung in Phosphor-Yliden: Photolyse von thiophosphoranylsubstituierten (Triphenylphosphoranyliden)methanen Cleavage of Ylidic Bonds in Phosphorus Ylides: Photolysis of Thiophosphoranyl-Substituted (Triphenylphosphoranylidene)methanes  
 Abstract    The thiophosphoranyl-substituted (triphenylphosphoranylidene)methanes 1, 6 a, b are cleaved photolytically (/ > 300 nm, 3 d, 0 °C) to yield triphenylphosphane and the thio-aza-phosphetanes 3 and 8 a, b, b', respectively. The formation of these heterocycles is explained in­ voking insertion o f the carbenes 2 and 7 a, b into the methine CH bond of one of the isopropyl groups. If 6a is irradiated for 16 h in the presence of the phosphanes P(NM e2)3, P(OMe)3 or P("Bu)3, the new ylides 9 a, b, c are obtained along with small quantities of 8 a. These results indicate a cleavage of the ylidic bond in 1 and 6a, b. The failure of attempted cyclopropana-tion reactions of olefins as well as the absence of the expected product o f a 1,2-H shift, 10, in the case of the photolysis of 6b leave doubts as to the occurrence of free carbenes. 
  Reference    Z. Naturforsch. 45b, 170—174 (1990); eingegangen am 26. Mai/23. August 1989 
  Published    1990 
  Keywords    Phosphorus Ylides, Photolysis, N M R Spectra, MS Spectra 
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 TEI-XML for    default:Reihe_B/45/ZNB-1990-45b-0170.pdf 
 Identifier    ZNB-1990-45b-0170 
 Volume    45 
5Author    G. Ourkrishna, D. Asm Ohapatraa, ThomasW. Olffb, G. Ünther, Von BünauRequires cookie*
 Title    Photochemistry in Porous Materials, II [1] Photolysis of Benzoin Ethers in Silicalite  
 Abstract    Four benzoin ethers 1 (a: methyl-, b: ethyl-, c: isopropyl-, d: phenylether) were photolyzed inside the channel system o f silicalite S -115, a novel type o f zeolite. Products which could be separated from the zeolite framework in various relative yields were pinacol ethers (from a, b, c), benzil (a-d), benzaldehyde (a-d), benzoates (a-d), and phenol (d). W hile the former three types o f products clearly arise from Norrish type I cleavage o f the parent molecules, a mecha­ nism involving the enolic form o f the benzoin ethers is proposed in order to explain the forma­ tion o f benzoates and phenol. 
  Reference    Z. Naturforsch. 47b, 1541 (1992); received May 18 1992 
  Published    1992 
  Keywords    Porous M aterials, Photolysis, Benzoin Ethers, Silicalite, Trapping 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-1541.pdf 
 Identifier    ZNB-1992-47b-1541 
 Volume    47 
6Author    Heinz-Peter Schuchmann, Heinz Bandmann, Clemens Von SonntagRequires cookie*
 Title    The 185 nm Photolysis of 1,4-Dioxane in the Liquid Phase  
 Abstract    The main products in the 185 nm photolysis of neat 1,4-dioxane are formaldehyde (0 = 0.25), glycol monovinyl ether (0.17), and ethylene (0.15). Some hydrogen (0.04), carbon monoxide (0.01), acetaldehyde (0.03), oxetane (0.04), and bidioxanyl (0.01) are also formed. On N20-saturation, the quantum yields of these products are diminished by about 30%, and N2 (0.59) and hydroxydioxane (0.4) become the main products. They are thought to be formed in the reaction sequence hv dioxane > • dioxane* dioxane* + N20 > • dioxane + N2 + O O + dioxane > • hydroxydioxane In aqueous dioxane, photoionisation is possible due to a greater lowering of the ionisa-tion threshold. In dioxane/water 20:80 the main products are H2 (0.50) and bidioxanyl (0.45), most likely formed in consequence of (dioxane)aq (dioxane)aq + eäq (dioxane)Jq • (dioxane-H)-+ H+ eäq + H+ > H-H-+ dioxane >-H2 + (dioxane-H)-2 (dioxane-H)- • bidioxanyl 
  Reference    Z. Naturforsch. 34b, 327—332 (1979); received October 6 1978 
  Published    1979 
  Keywords    Photolysis, 1, 4-Dioxane, Photoionisation, Energy Transfer, Quantum Yields 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0327.pdf 
 Identifier    ZNB-1979-34b-0327 
 Volume    34 
7Author    H. Kunkely, A. VoglerRequires cookie*
 Title    Photoredox Decomposition of [Cobalamin-^-NC-Fen(CN)5]3* Induced by Metal-to-Metal Charge Transfer Excitation  
 Abstract    In the presence of oxygen aqueous solutions of the binuclear complex [cobalamin-^-NC-Fe(C N)5]3' undergo a redox photolysis (0 ~ 2 x 10'3 at Airr = 405 nm) which yields aquocoba-lamin and [Fe(C N)6]3\ It is suggested that this photoreaction is induced by direct metal-to-metal charge transfer (M M CT) excitation. On the contrary, [cobalamin-fx-NC-Ru(CN)5]3' is photo-inert because a reactive MMCT state is not accessible. 
  Reference    Z. Naturforsch. 51b, 245 (1996); received July 7 1995 
  Published    1996 
  Keywords    Vitamin B I2, Photolysis, Electron Transfer, Cyano Complexes, Iron 
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 TEI-XML for    default:Reihe_B/51/ZNB-1996-51b-0245.pdf 
 Identifier    ZNB-1996-51b-0245 
 Volume    51