Photochemistry and photophysics of phosphinoyl-containing compounds

Photochemistry and photophysics of various substituted phoshine oxides have been investigated. When the absorbing chromophore have been deliberately changed from n, pi* absorption of an aromatic ketone to pi, pi* absorption of a polycyclic aromatic compound such as naphthalene, different photochemical behavior from analogous phenyl derivatives, which are known to efficiently produce radicals, is observed.; (1-Naphthoyl)diphenylphosphine oxide has high triplet quantum yield but yields few radicals that can be detected by either laser flash photolysis or pulse radiolysis.; Efficient radical generation from substituted benzyldiphenylphosphine oxide takes place upon 254 irradiation. There are total of over 20 photoproducts. Significant reaction selectivity with simplified photoproducts is achieved in a solid matrix as well as in microcapsules.; o-Nitrobenzyldiphenylphosphine oxide undergoes an efficient intramolecular hydrogen abstraction process with photochromic properties. In contrast, substituted o-nitrobenzyldiphenylphosphinates can further proceed rearrangements and decompositions to give products. Photochemical mechanisms are elucidated and elusive photoproducts are isolated and characterized.