Published in Zeitschrift für Naturforschung C
Monomolecular films of 9-cis, 11-cis, 13-cis and all-trans retinal were formed at an air-water interface. Area/molecule and surface potential were measured before, during and after illumination. The initial quantum yield of the photoisomerization of 9-cis retinal was 0.25. Irradiation of a retinal monolayer resulted in 30 to 60 mVolt changes in sur...
Published in Proceedings of the National Academy of Sciences of the United States of America
Multielectron storage and hydrogen generation by light is achieved in aqueous dispersions of ultrafine TiO(2) particles (120-A diameter) when the amphiphilic viologen derivative N-tetradecyl-N'-methyl-4,4'-dipyridinium dichloride (C(14)MV(2+)) is used as an electron relay. Consecutive reduction of C(14)MV(2+) to the radical ion (C(14)MV(+)) and neu...
A smog chamber arrangement is presented for the study of aerosol forming photoreactions and is tested by first determinations of aerosol residence times. The automatic monitor for sulphuric acid and sulphate of the TU Berlin has been used for sensitive measurements of sulphuric acid and other particulate sulphur aerosols under the condition of a sm...
Published in Theoretical and Experimental Chemistry
The effect of UV or visible light on solutions of 1-benzoyloxy-4-[4-(dimethylamino)styryl]pyridinium salts in acetonitrile solution lead to cleavage of the N—O bond and formation of 4-[4-(dimethylamino)styryl]pyridine.
Published in Bioconjugate Techniques
Published in Chemistry (Weinheim an der Bergstrasse, Germany)
Herein we report on metal-free C-C coupling reactions mediated by the pyridine derivative 2,3,6,7-tetrakis(tetramethylguanidino)pyridine under the action of visible light. The rate-determining step is the homolytic N-C bond cleavage of the initially formed N-alkyl pyridinium ion upon excitation with visible light. The released alkyl radicals subseq...
Published in Chemistry (Weinheim an der Bergstrasse, Germany)
The photobromination of C-H bonds by using molecular bromine was reinvestigated under microfluidic conditions. The continuous-flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated products with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide gr...
Published in Pure and Applied Chemistry
Published in Angewandte Chemie (International ed. in English)
A photo-induced substitutive introduction of an aldoxime functional group to carbon chains was achieved using photo-excited 4-benzoylpyridine as a C(sp(3) )-H bond cleaving agent and arylsulfonyl oxime as an aldoxime precursor. The non-acidic C-H bonds in various substances, including cycloalkanes, ethers, azacycles, and cyclic sulfides, were chemo...
Published in Angewandte Chemie (International ed. in English)
The photoinduced regio- and enantioselective coupling of naphthols and derivatives thereof is achieved in the confined chiral coordination space of a RuII metalloligand based cage. The racemic or enantiopure cages encapsulate naphthol guests, which then undergo a regiospecific 1,4-coupling, rather than the normal 1,1-coupling, to form 4-(2-hydroxy-...
