Novel unsaturated N-phenyl-alpha-amino esters were synthesized in isolated yields of 50 to 10% by visible light irradiation of methanolic suspensions of silica-supported cadmium sulfide in the presence of methyl (2Z)-phenyl(phenylimino)acetate and various cyclic olefins. A semiconductor photocatalysis mechanism is proposed for this linear addition reaction. The light-generated electron-hole pair in the oxidative step induces a dissociative electron transfer from the olefin to CdS affording a proton and an allylic radical, whereas in the reductive step an alpha-aminobenzyl radical is formed in a proton coupled reaction.
View Article and Find Full Text PDFClinical chemistry and laboratory medicine developed rapidly in the industrialised world after the Second World War, as evidenced by the recruitment of physicians and natural scientists, the intensive development of methods and technologies, the founding of societies such as the IFCC, and the organisation of scientific life. In East Germany a working group of clinical pathologists and chemists came together in 1960, out of which grew the Gesellschaft für Klinische Chemie und Laboratoriumsdiagnostik (Society for Clinical Chemistry and Laboratory Diagnostics) in 1968. Within the socialist health care system laboratory services were structured in a pyramid form based on the country's governmental districts.
View Article and Find Full Text PDFAmorphous, microporous TiO hybrid semiconductors modified with transition metals induce generation of a photocurrent and photocatalytic degradation of the water contaminant 4-chlorophenol through photoinduced charge separation (the postulated mechanism is shown in the picture, Ar=4-ClC H ). In contrast to the previously known crystalline titania photocatalysts, which are active only when excited with UV light, the amorphous semiconductors modified with platinum, rhodium, and gold chloride enable both processes also with visible light.
View Article and Find Full Text PDF