Linear and Nonlinear Optical Properties of Diiron μ-Vinylcarbyne Acceptor and Stilbenyl Donor Based Chromophores

Abstract

Ionic [(CpFeCO)2(μ-CO)(μ-CCHCH−)]+ fragments were used as electron acceptors in combination with para-substituted stilbenyl donors to form push−pull chromophores. These μ-vinylcarbyne salts were prepared by two complementary procedures: (a) the direct condensation of the μ-ethylidyne complex [(CpFeCO)2(μ-CO)(μ-CCH3)][BF4] with various stilbenyl aldehydes and (b) the preparation and reaction of the neutral aldehyde [(CpFeCO)2(μ-CO)(μ-CCHCH2C6H4CHO)] with Wittig reagents followed by hydride abstraction using [Ph3C][BF4]. While the series did exhibit high nonlinear activity (measured by hyper-Rayleigh scattering techniques), fluorescence checks revealed emission bands in the proximity of the second harmonic signal due to two-photon absorption.