Non-linear optical properties of the mixed-metal mixed-chalcogen clusters [Fe2(CO)6?μ-SeC(Ph)=C(Se)??(OEt)C=Cr(CO)5?] and [Fe2(CO)6Se2?μ-(CO)3Cr(η5-C5H(CH2Ph)(Ph)(OEt)?]

Abstract

We report studies of the third-order optical non-linearity of the newly synthesized butterfly-shaped mixed-metal mixed-chalcogen clusters wFe2_CO.6_m-SeC_Ph.5C_Se.4__OEt.C5Cr_CO.54x and wFe2_CO.6Se2_m-_CO.3Cr_h5- C5H_CH2Ph._Ph._OEt.4x using 532 nm, 6 ns laser pulses. Their effective non-linear absorption coefficient and non-linear index intensity coefficient are measured by the z-scan technique from which the corresponding cubic hyperpolarizabilities are evaluated. The obtained values indicate a high non-linearity comparable to some of the best values reported previously for cluster compounds. Both compounds show strong optical limiting, and the second compound exhibits non-linear scattering. Their photostability is superior to many of the previously reported highly non-linear clusters. q1999 Elsevier Science B.V. All rights reserved.