Janet B. Foley and Angela Herring. Bennington College, Bennington, VT
Two complexes, cis(1) and trans(2)-(AupNBT)2dppee [pNBT = para-nitrobenzenethiol; dppee = bis(diphenyl)phosphinoethylene] have been synthesized and characterized. X-ray diffraction studies show the cis-(AupNBT)2dppee has a gold-gold distance of 2.9Å and the trans-(AupNBT)2, which luminesces orange under UV light, is a dimer with an intermolecular gold-gold distance of 3.1Å. We have used UV-vis and 1H NMR spectroscopy to investigate the photochemical reactivity of both complexes. In a range of organic solvents, the cis-(AupNBT)2dppee readily isomerizes to the trans isomer. In chlorinated solvents, when photolyzed with wavelengths up to 375 nm., the trans-(AupNBT)2dppee undergoes a photochemical substitution to form trans-(AuCl)2dppee whose crystal structure is an extended chain with intermolecular gold-gold distances of 3.0202 Å plus the 4-nitrobenzenedisulfide, presumably by a radical mechanism.