Bis-dithiobenzilnickel complexes for usae in near-infrared absorbing materials and benzoin derivatives as intermediates therefor

摘要

A benzoin compound is synthesized from phenylglyoxal and a substituted benzene, and the resulting benzoin compound is converted to a bis-thiobenzilnickel complex using phosphorus pentasulfide/nickel chloride. The resulting bis-thiobenzilnickel complex of Formula [1] and/or [2]: (wherein R₁ to R₅ are the same or different, and denote substituted or unsubstituted alkyl, cycloalkyl, alkoxy, aryl, aryloxy, halogen atom, or hydrogen atom, except for substituted or unsubstituted amino group and alkoxyalkoxy group. However, a case where all of R₁ to R₅ are hydrogen atoms is excepted.) contains two phenyl groups and two substituted phenyl groups and is useful as a near-infrared absorbing material in, for example, optical recording materials and molding compositions containing transparent resins.