Chiral organometallic chromophores for nonlinear optics derived from [Fe2(η5-C5H5)2(CO)2(μ-CO)(μ-CCH3)]+ [BF4]−

Two series of chiral organometallic Donor-π-Acceptor chromophores derived from [Fe2(η5-C5H5)2(CO)2(μ-CO)(μ-CCH3)]+ [BF4]− have been synthesised. In the first series (S)-(−)-2-methoxymethyl pyrrolidine acts as the chiral donor end group and in the second series 1,1′-binaphthyl acts as the chiral π-bridging unit. The nonlinear optical properties of these compounds were measured by the Kurtz powder technique and by hyper-Raleigh scattering. β-values of up to 964×10−30 esu were obtained for a member of the first series. Single crystal X-ray studies of [Fe2(η5-C5H5)2(CO)2(μ-CO)(μ-CCH3)]+ [BF4]−, [Fe2(η5-C5H4CH3)2(CO)2(μ-CO)(μ-(E)-CCHCH-2-(5-piperidin-1-yl-thiophene))]+ [BF4]− and [Fe2(η5-C5H4CH3)2(CO)2(μ-CO)(μ-(E)-CCHCH-2-(naphthalene))]+ [BF4]− are reported.