Organometallic dyes: Part 1. Synthesis of orange to cyan dyes based on donor–conjugated–acceptor chromogenes using ferrocene as the donor group

Abstract A novel series of organometallic donor–conjugated–acceptor dyes derived from ferrocene as the donor group have been synthesized via the Knoevenagel reaction of ferrocene carboxaldehyde and various active methylene compounds to give a range of dyes ranging from orange to blue–green in color. The most bathochromic dye is that derived from dialkyl thiobarbituric acid and the least is that derived from the tetralone. The dyes showed an unusual negative solvatochromism as the solvent polarity increased. All dyes synthesized are expected to have some non‐linear optical properties, as evidenced from the pronounced solvatochromism. Copyright © 2001 John Wiley & Sons, Ltd.