Nonlinear optical properties of mixed Mo/Fe, mixed chalcogen clusters Cp2Mo2Fe2STe(CO)(7) and Cp2Mo2Fe2(mu 3-S)(mu 3-Te)(mu 2-SPh)(mu 3-H)(CO)(5)

Studies of the third order optical nonlinearity of the mixed-metal, mixed c halcogen clusters Cp2Mo2Fe2STe(CO)(7) and Cp2Mo2Fe2(mu 3-s)(mu 3-Te)(mu 2-S Ph)(mu 3-H)(CO)(5) using 532 nm, 6 ns laser pulses are reported. The second compound is the first example in literature of a mixed Fe/Mo mixed chalcog en complex containing a bridging thiolate group. The effective nonlinear ab sorption coefficient and nonlinear index intensity coefficient of these com pounds are measured by the Z-scan technique, from which the corresponding c ubic hyperpolarizabilities are evaluated. The obtained values indicate a hi gh nonlinearity comparable to some of the best values reported previously f or cluster compounds. Both compounds show strong optical limiting. In addit ion, their photostability is found to be much superior to many of the previ ously reported highly nonlinear clusters. (C) 2000 Published by Elsevier Sc ience B.V. All rights reserved.