| | 2 | Author
| Jürgen Keim | Requires cookie* | | | Title
| Ein Beitrag zur Photochemie aromatischer Nitroverbindungen, III* A Contribution to the Photochemistry of Aromatic Nitro Compounds  | | | | Abstract
| During UV irradiation of nitrobenzene and some derivatives in benzene solution biphenyls are formed as in the case of the corresponding iodobenzenes. Using fluorobenzene as a solvent, isomeric fluorobiphenyls (o, TO, p) will be found as reaction products having a definite distribution (o >m > p), which is characteristic for substitution by radicals. Therefore, we conclude that the CN-bond is split homolytically. Besides the biphenyls, other important reaction products of the aromatic nitro compounds -phenols and nitro-phenols -are identified. | | | |
Reference
| Z. Naturforsch. 34b, 995—998 (1979); eingegangen am 28. Februar 1979 | | | |
Published
| 1979 | | | |
Keywords
| Photochemistry, Aromatic Nitro Compounds, UV | | | |
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| | | | | TEI-XML for
| default:Reihe_B/34/ZNB-1979-34b-0995.pdf | | | | Identifier
| ZNB-1979-34b-0995 | | | | Volume
| 34 | |
| 3 | Author
| H. Parlar+, Y. Inanici++ | Requires cookie* | | | Title
| Eine nicht erwartete intramolekulare Photoreaktion eines Hexachloroctahydrodimethanonaphthalins | | | | Abstract
| Photoreactions of 1,2,3,4,10,10-hexachloro-6,7-epoxy-l,4,4a,5,6,7,8,8a-octahydro-l,4-endo, endo-5,8-dimethano-naphthaline (1) were stud-ied in acetone with wavelengths above 290 nm. With the help of column chromatography an unusual isomerisation product (4) could be isolated, whose structure was established by spectral data obtained by mass spectrometry infrared spectroscopy, X H and 13 C nuclear magnetic resonance measurements. Hexachloroctahydrodimethanonaphthaline gehö-ren zu den bekanntesten Cyclodieninsektiziden, | | | |
Reference
| (Z. Naturforsch. 36b, 125—126 [1981]; eingegangen am 12. August 1980) | | | |
Published
| 1981 | | | |
Keywords
| Photochemistry, Isomerisation Reactions, Hexachlorooctahydrodimethanonaphthalines | | | |
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| default:Reihe_B/36/ZNB-1981-36b-0125_n.pdf | | | | Identifier
| ZNB-1981-36b-0125_n | | | | Volume
| 36 | |
| 4 | Author
| Arnd Vogler, Josef Kisslinger, WarrenR. Roper | Requires cookie* | | | Title
| Photochemistry of Osmium-Carbyne Complexes | | | | Abstract
| Upon charge transfer (Os to carbyne) excitation the carbyne complexes Os(CPh)(CO)(PPh3)2Cl and [Os(CPh)(CO)2(PPh3)2] + with Ph = C6H5 are converted to the carbene complex Os(CHPh)(CO)(PPh3)2Cl2 in solutions containing HCl. It is suggested that the relaxed CT state can be described as square-pyramidal Os(II) complex containing a bent carbyne ligand which carries a lone pair at the coordinating carbon atom. Product formation occurs by the addition of a proton to the carbyne ligand and by attaching a chloride to the osmium completing an octahedral coordination. The cationic carbene complex thus formed is apparently not stable but undergoes a substitut ion of a CO ligand by chloride. | | | |
Reference
| Z. Naturforsch. 38b, 1506—1509 (1983); received July 5 1983 | | | |
Published
| 1983 | | | |
Keywords
| Photochemistry, Carbyne Complexes, Osmium Complexes | | | |
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| default:Reihe_B/38/ZNB-1983-38b-1506.pdf | | | | Identifier
| ZNB-1983-38b-1506 | | | | Volume
| 38 | |
| 6 | Author
| Arnd Vogler, Alfred Kern | Requires cookie* | | | Title
| Photoredox Reaction of Jrans-4-Stilbenecarboxylatopentaamminecobalt(III) | | | | Abstract
| The irradiation (A = 313nm) of aqueous [Co(III)(NH3)5TSC] 2 + (TSC -= transA-stilbenecarboxylate) leads to a redox reaction with formation of Co 2+ as has been shown previously. The TSC -ligand is oxidized to the radical in the primary photoreaction. At higher complex concentrations IO -2 M) this TSC radical is oxidized to stable products (0 = 0.09 ± 0.02) by [Co(NH3)5TSC] 2 +, which is reduced to Co 2 + leading to release of the TSC" ligand (0 = 0.07 ± 0.02). Co 2 + is thus formed by both the secondary and the primary photochemical reaction (ÖWraii = 0.16). At low complex concentrations (< 10 -4 M) in the presence of air, the primary TSC radical is scavenged by O2. Benz-aldehyde is an oxidation product. This reduces the formation of Co 2 + to 0 = 0.09 ± 0.02, which is taken to be the efficiency of the primary photochemical step. It is suggested that the photoredox reaction is initiated by an electron transfer from the first excited singlet of the TSC -ligand. As shown by sensitization experiments, the population of the lowest TSC -triplet leads to the usual trans/cis isomerization of the TSC -ligand, but not to the redox reaction. | | | |
Reference
| Z. Naturforsch. 34b, 271—274 (1979); received November 13 1978 | | | |
Published
| 1979 | | | |
Keywords
| Redox Reaction, Photochemistry, Cobalt(III) Complex, Stilbenecarboxylate | | | |
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| default:Reihe_B/34/ZNB-1979-34b-0271.pdf | | | | Identifier
| ZNB-1979-34b-0271 | | | | Volume
| 34 | |
| 8 | Author
| Wolfgang Gerhartz, Friedrich-Wilhelm Grevels, WernerE. Klotzbücher, ErnstA. Koerner Von Gustorf, RobinN. Perutz | Requires cookie* | | | Title
| Low-Temperature Matrix Photochemistry of (f/ 4 -Diene)tetracarbonylchromium Complexes | | | | Abstract
| Photolysis of (^ 4 -diene)Cr(CO) 4 complexes (diene = butadiene, trans,trans-2,4-hexadiene, 2,3-dimethylbutadiene) in Ar, N 2 , and CO matrices at 10-12 K was monitored by infrared and UV-Vis spectroscopy. In argon and dinitrogen matrices loss of CO ist the predominant photoreaction. The resulting fac-(rf-diene)Cr(CO) 3 can take up N 2 from the matrix to form (?7 4 -diene)Cr(CO) 3 (N 2). In the case of the hexadiene complex this process requires matrix an-nealing subsequent to photolytic loss of CO. Photolysis in CO matrices, by contrast, results in stepwise displacement of the diene ligand, yielding (/7 2 -diene)Cr(CO) 5 and ultimately Cr(CO) 6 . | | | |
Reference
| Z. Naturforsch. 40b, 518—523 (1985); received November 13 1984 | | | |
Published
| 1985 | | | |
Keywords
| Matrix Isolation, Photochemistry, Carbonylchromium Diene Complexes, IR Spectra | | | |
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| default:Reihe_B/40/ZNB-1985-40b-0518.pdf | | | | Identifier
| ZNB-1985-40b-0518 | | | | Volume
| 40 | |
| 9 | Author
| Karin Oldenburg, Arnd Vogler | Requires cookie* | | | Title
| Electronic Spectra and Photochemistry of Tin(II), Lead(II), Antimony(III), and Bismuth(III) Bromide Complexes in Solution | | | | Abstract
| The electronic spectra o f brom o complexes o f main group metal ions with an s2 electronic configuration (SnBr3~, PbBr3~, PbBr42_, SbBr4~, SbBr63~, BiBr4~, BiBr63~) in acetonitrile show long-wavelength absorption bands which are assigned to metal-centered sp transitions. C om pared to the corresponding chloro complexes the sp bands o f the bromo complexes appear at longer wavelength due to sp/LM C T mixing (LM CT = ligand-to-metal charge transfer). As a result o f this mixing the luminescence which originates from low-energy sp excited states is much weaker than that o f the chloro complexes. M oreover, some o f the bromo complexes (e.g. BiBr4~) undergo a photochemical redox decom position induced by LMCT excitation. | | | |
Reference
| Z. Naturforsch. 48b, 1519—1523 (1993); received July 1 1993 | | | |
Published
| 1993 | | | |
Keywords
| Electronic Spectra, Bromo Complexes, Main Group M etals, Photochemistry | | | |
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| default:Reihe_B/48/ZNB-1993-48b-1519.pdf | | | | Identifier
| ZNB-1993-48b-1519 | | | | Volume
| 48 | |
| 10 | Author
| Horst Kunkely, AmD. Vogler | Requires cookie* | | | Title
| Photoreactivity of Titanocene Pentasulfide | | | | Abstract
| The electronic spectrum o f Cp2TiSs shows a long-wavelength absorption at Am ax = 492 nm which is assigned to the lowest-energy S52~ ^ T i IV ligand-to-metal charge transfer (L M C T) transition. The photolysis o f the complex in C H 2CI2 leads to the formation o f Cp2T iC l2 and elemental sulfur. It is suggested that L M C T excitation initiates a reductive elimination with the extrusion o f S5 while the reduced titanocene is reoxidized by the solvent. | | | |
Reference
| Z. Naturforsch. 53b, 224—226 (1998); received December 12 1997 | | | |
Published
| 1998 | | | |
Keywords
| Charge Transfer, Titanium Complexes, Sulfide Complexes, Photochemistry | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0224.pdf | | | | Identifier
| ZNB-1998-53b-0224 | | | | Volume
| 53 | |
| 16 | Author
| Friedrich-Wilhelm Grevels, Konrad Schneider, Carl Krüger, Richard Goddard | Requires cookie* | | | Title
| Tricarbonyl(^ 4 -1.5-cümethylen-2.6-cümethylcyclooctan)eisen: photochemische Synthese und Struktur Tricarbonyl(^ 4 -l,5-dimethylene-2,6-dimethylcyclooctane)iron: Photochemical Synthesis and Structure | | | | Abstract
| Extended photolysis of pentacarbonyliron in neat 2,3-dimethylbutadiene results in dimerization of the diene and formation of tricarbonyl(?y 4 -l,5-dimethylene-2,6-dimethyl-cyclooctane)iron (1). The structure of complex 1 is characterized by a trigonal-bipyramidal geometry whereby the exocyclic double bonds of the diene ligand and one of the carbonyl groups lie exactly in the equatorial coordination plane. | | | |
Reference
| Z. Naturforsch. 35b, 360—365 (1980); eingegangen am 5. November 1979 | | | |
Published
| 1980 | | | |
Keywords
| Carbonyliron Olefin Complexes, Dimerization of Dimethylbutadiene, Photochemistry, NMR, X-ray | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0360.pdf | | | | Identifier
| ZNB-1980-35b-0360 | | | | Volume
| 35 | |
| 17 | Author
| HeinzG 0 Becker, Dietmar Pfeifer, Reiner Radeglia | Requires cookie* | | | Title
| Democratic Republic | | | | Abstract
| 13 C and 15 N photo-CIDNP effects were determined for the reversible electron transfer from pyrene to arene diazonium salts on excitation of the charge transfer band at 360 nm. The diazonium salts being the products of back electron transfer ("cage products") show enhanced absorption for 13 C(1) and the 15 N-enriched diazonium group, whereas the escape products, ArH or lö N2, respectively, yield emission signals. It was shown that the inten-sities of the CIDNP effects depend on the rates of intersystem crossing kjSC within the geminate radical pair, i.e. on the magnetic nucleus used as a probe of the CIDNP effect. Using iH, 13 C or 15 N the time domain of observation can be manipulated in the ranges of 90-100 ns, 15-20 ns and 3-5 ns, respectively. Furthermore, the CIDNP intensities depend on the proper balance of the rate of electron back transfer, k_e, and the rate kp of formation of the escape product. Since k_e increases with increasing energy of the geminate radical pair, this balance and therefore the CIDNP intensities vary according to the substituent present and the electron donor used. | | | |
Reference
| Z. Naturforsch. 38b, 1591—1597 (1983); received April 6 1983 | | | |
Published
| 1983 | | | |
Keywords
| Photochemistry, Dediazoniation, Electron Transfer, Chemical Induced Nuclear Polarization (CIDNP), Arene Diazonium Salts | | | |
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| default:Reihe_B/38/ZNB-1983-38b-1591.pdf | | | | Identifier
| ZNB-1983-38b-1591 | | | | Volume
| 38 | |
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