A facile organolithium route to ferrocene-based triarylmethyl dyes with substantial near IR and NLO properties

A series of triarylmethanol derivatives containing combinations of phenyl, 1-naphthyl, 4-dimethylamino-4′-stilbenyl, ferrocenyl or 4-[2-ferrocenylethenyl]phenyl groups have been prepared by reaction of 4-[4-Me₂NC₆H₄CC]C₆H₄Li or 4-[FcCC]C₆H₄Li (Fc = ferrocenyl) with ferrocenecarboxaldehyde, ferrocenyl phenyl ketone, methyl ferrocenecarboxylate, 1-naphthyl phenyl ketone, ethyl benzoate or diethyl carbonate. The carbinols readily form the corresponding intensely coloured carbenium ions in acid solution which have significant electronic absorption in the near infrared. Initial studies indicate that they also possess substantial first hyperpolarisabilities.