Ferrocene in Conjugation with a Fischer Carbene: Synthesis, NLO, and Electrochemical Behavior of a Novel Organometallic Push−Pull System

Using an iterative sequence of Wittig olefination, reduction, oxidation, and condensation of an active methylene group to carbonyl, it was possible to prepare a series of organometallic push−pull molecules [(CO) 5 M C(OCH 3 )(−CH CH−) n (C 5 H 4 )Fe(C 5 H 5 ), M = W, Cr, n = 1−4] in which ferrocene is the donor element and a Fisher carbene moeity is the acceptor group. The molecular first hyperpolarizability β was determined by hyper-Rayleigh scattering experiments. The β values ranged from 110 × 10 - 30 to 2420 × 10 - 30 esu in acetonitrile, and they are among the highest reported for organometallic molecules so far. Electrochemical measurements are consistent with the push−pull nature of these compounds.