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)5MC(OCH3)(−CHCH−)n(C5H4)Fe(C5H5), 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.