Photochemistry of charge transfer complexes of styrene derivatives with tetranitromethane. X-ray crystal structure of a novel dimeric adduct from p-methylstyrene

Styrene and its derivatives form coloured charge transfer complexes with tetranitromethane as the acceptor. These complexes are stable in acetonitrile under neutral conditions in the dark for several days. Photochemistry of these complexes was found to be highly dependent on the structure and substituent effects on the styrene. The structure of the dimeric adduct 2b from p-methylstyrene is determined by X-ray crystallography and it clearly establishes the ambident reactivity of the trinitromethide anion to act as an oxygen nucleophile in the present case, which is in contrast to its well known reactivity as a carbon nucleophile in the previously reported adducts from other aromatic substrates.