Rational synthesis, structural characterization and the third-order nonlinear optical properties of two new M-Cu-S (M = Mo or W) clusters

By the additional reaction of binuclear compounds (Me4N)(2)M2S4 (TDT)(2) (M = Mo, W; H2TDT = H2CH3C6H3S2) with mononuclear cuprous complex, two new M- Cu-S clusters Mo2Cu2S4 (TDT)(2)-(PPh3)(2) . CH3CH2OH (1) and W2Cu2S4 (TDT)( 2) (PPh3)(2) . 0. 5CH(3)CH(2)OH . 0. 5H(2)O (2) have been prepared and char acterized by IR, UV-Vis, P-31 MMR spectroscopy, cyclic voltammetry and sing le crystal X-ray structure analysis. Both compounds crystallize in space gr oup P 2(1) / n with lattice parameters a = 1.0956(3), b = 2.2072(3), c = 2. 4340(3) nm, beta = 100.36(2)degrees, V = 5.790(3) nm(3) and Z = 4 for 1 and a = 1.0965(9), b = 2.2135(3), c = 2.4317(4) nm, beta = 99.63(8)degrees, V = 5.819(8) nm(3) and Z = 4 for 2. Both molecular structures contain a cuban e-like cluster core [M2Cu2S4] (M = Mo, W) and their skeletons are almost th e same except for M atoms. The syntheses, structures and spectrum character izations of these two clusters are discussed. The third-order nonlinear opt ical (NLO) property of the two clusters was studied by the technique of for ward degenerate four-save mixing (DFWM) for the first time and these cluste rs exhibited relatively large nonlinear optical coefficients.