THE LINEAR AND NONLINEAR-OPTICAL PROPERTIES OF SOME CONJUGATED FERROCENE COMPOUNDS WITH POTENT HETEROCYCLIC ACCEPTORS

We have synthesized donor-acceptor chromophores containing ferrocene a s the donor and several different heterocyclic accepters. In each case the chromophores have an intense band at low energy which is ascribed to a metal to ligand charge-transfer band. Neutral compounds containi ng the 1,3-diethyl-2-thiobarbituric acid and dicyanomethylene-2, 3-dih ydrobenzothiophene-1, 1-dioxide accepters have large first molecular h yperpolarizabilities (beta) in comparison to a previously examined com pound 1-ferrocenyl-2-E-(4-nitrophenyl)ethylene, as measured by electri c field induced second harmonic generation (EFISH), in chloroform, wit h 1.907 mu m fundamental radiation. Incorporation of 1-ferrocenyl-4-E, E(4-nitrophenyl)butadiene into polymethylmethacrylate at 2% molar load ing, yielded after poling at 100 V mu m(-1), a polymer film with an r( 33) = 0.8 pm V-1 measured at 820 nm.