Syntheses, Structures and Optical Nonlinearities of Heteroselenometallic W–Se–Cu Cluster Compounds Containing Bridging Phosphane Ligands

Treatment of [Et4N](2)[WSe4] with the trinuclear trigonal-bipyramidal copper(I) complexes [CU3(mu(3)-X)(2)(mu-L)(3)]X [X = I, L'= bis(diphenylphosphanylimethane (dppm) (1a); X = Cl, L = bis(diphenylphosphanyl)amine (dppa) (1b)] affords the tetranuclear cluster compounds [(mu(3)-WSe4)CU3(mu-X)(mu-L)(2)] [X = I, L = dppm (2a); X = Cl, L = dppa (2b)], which exhibit an open butterfly configuration. Interaction of [Et4N]2[WSe4] with [Cu(MeCN)(4)][PF6] and L gives the pentanuclear cluster compounds [(mu 4 center dot WSe4)CU4(P-L)(4)][PF6](2) [L = dppm (3a), dppa (3b)] which contain an open co-planar WCU4 core. The solid-state structures of cluster compounds 2a, 2b, and 3a have been established by X-ray crystallography. The nonlinear optical properties of 2a and 3a have been examined by z-scan techniques with 7-ns pulses at 532 nm. The pentanuclear coplanar cluster 3a exhibits a large optical limiting effect (the limiting threshold is about 0.40 Jcm(-2)). ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)