Preparation of Thiophene-Coordinated Ruthenium Complexes for Nonlinear Optics

The new organometallic compounds [{(E)-2-SC4H3CHCHC6H4-X-p}Ru(C6Me6)][CF3SO3]2 (X = MeO (1), Me (2), H (3), Br (4), NO2 (5)), bearing a (thiophene)Ru(C6Me6)2+ fragment in the end group, have been prepared for nonlinear optical chromophores, and their hyperpolarizabilities have been measured by the HRS method. The static hyperpolarizability (β0) values of the complexes increase as the electron-acceptor power of the substituent X increases (MeO < Me < H < Br < NO2). Replacement of hexamethylbenzene with pentamethylcyclopentadienyl resulted in [{(E)-2-SC4H3CHCHC6H4-NO2-p}]Ru(C5Me5)]CF3SO3 (7), showing a significant increase in the hyperpolarizability. The substituent effects on β0 were studied by time-dependent DFT calculations.