SYNTHESIS AND CHARACTERIZATION OF SOME UNSYMMETRIC SUBSTITUTED BIS(DITHIOBENZIL)NICKEL COMPLEX DYES

A new unsymmetric substituted bis(dithiobenzil) nickel complex contain ing two phenyl groups and two substituted phenyl groups was synthesize d from a benzoin compound using phosphorus pentasulfide chloride. The benzoin compounds were prepared from phenylglyoxyal and substituted be nzenes. The nickel complexes were characterized by elemental analysis, MS, (HNMR)-H-1 and IR, The influence of substitutuents on the long wa velength absorption maxima of the nickel complexes was evaluated using the Hammett equation, they gave a pronounced effect relative to the c orresponding symmetric nickel complexes, some of them having maximum a bsorption around 830 nm, and are thus very promising for use as near-i nfrared absorbing dyes for optical data storage using a Ga-As semicond uctor laser diode. (C) 1997 Elsevier Science Ltd.