Synthesis and long wavelength hyper-Rayleigh scattering measurements of extended mu-vinylidene di-iron donor based organometallic merocyanines

The synthesis is reported of a series of extended pi -bridged organometalli c merocyanines linking the dicyanovinyl electron accepting group with the e lectron donating [(CpFeCO)(2)(mu -CO)(mu -C=CH-)] fragment. The chromophore s exhibited inverse solvatochromic shifts with increased medium polarity, w hich is because of interactions between dipolar or protic solvents and the dicyanovinyl unit. The nonlinear optical (NLO) properties of the chromophor es have been investigated using long wavelength (1500 nm) hyper-Rayleigh sc attering techniques to avoid both resonance and two-photon absorption enhan cement of the first hyperpolarisabilities. (C) 2001 Elsevier Science B.V. A ll rights reserved.