Synthesis, crystal structures and third-order nonlinear optical properties of a new family of double incomplete cubane-like clusters [(η5-C5Me5)2Mo2(μ3-S)3SCu2X(μ-X)]2 (X = Cl-, Br-, SCN-) and cubane-like clusters [(η5-C5Me5)2Mo2(μ3-S)4(CuX)2] (X = Br-, SCN-, CN-)

Reactions of trans-[(eta(5)-C5Me5)(2)Mo-2(mu-S)(2)S-2] (1) with 2 equiv. of CuX (X = Cl-, Br-, SCN-, CN-) in refluxing acetonitrile resulted in a new set of Mo/Cu/S cluster compounds [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(3)SCu2Cl(mu-Cl)](2) (2), [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(4)(CuBr)(2)] (3) and [(eta(5)- C5Me5)(2)Mo-2(mu(3)-S)(3)SCu2Br(mu-Br)](2) (4), [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(4)(CuSCN)(2)] (5) and [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(3)SCu2(SCN)(mu-SCN)](2) (6) and [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(4)(CuCN)(2)] (7). Compounds 2-7 were fully characterized by elemental analysis, IR, UV-Vis, H-1 NMR and single-crystal X-ray crystallography. Compounds 2, 4 and 6 consist of two incomplete cubane-like [(eta(5)-C5Me5)(2)Mo-2(mu(3)-s)(3)SCu2X] species bridged by a pair of mu-X- anions while 3, 5 and 7 contain a cubane-like [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(4)Cu-2] core with each of two terminal X- coordinated at each copper(I) center. The third-order nonlinear optical (NLO) properties of 2-5 and 7 along with [(eta(5)-C5Me5)(2)Mo-2(mu(3)-S)(4)(CuCl)(2)] in CH2Cl2 were investigated by using Z-scan technique at 532 nm. All these clusters showed strong third-order NLO absorption effects and self-defocusing properties. (c) 2007 Elsevier B.V. All rights reserved.