Solid state reaction of [NH4]2[MoS2O2], CuI and Et4NBr with 2-) diphenylphosphino) pyridine (PyPPh2) results in trinuclear cluster MoOS3Cu2(PyPPh2)3]. Its crystal structure has been determined on a Simens Smart 1-K CCD area-detector diffractometer. The crystal is triclinic, space group P1 with a=1.16736(4)nm, b=1.42254(5)nm, c=1. 68034(6)nm, α=100.07°, β=103.2450(10)°, γ=105.0650(10)°, V=2. 53991(15) nm^3, Z=2 , Dc=1.504g·cm^-3, F(000)=1166, μ=13.57cm^-1. The final R1=0.0590, wR2=0.1238. The cluster is highly bent with a butterfly-shaped core in which the MoOS3^2- unit acts as a tridentate ligand to coordinate with two Cu atoms of different configurations and the O atom serves as a terminal group. Investigation of third- order optical nonlinearity shows that it exhibits considerable nonlinear absorptive and self-defocusing effect with α2=4.4×10^-11m ·W^-1 and n2=-8.225×10^-18m^2·W^-1,respectively. The peripheral ligands also play an important role in the NLO properties of clusters.

Key words: PYRIDINE P, MOLYBDENUM COMPLEX, COPPER COMPLEX, CRYSTAL STRUCTURE, NON LINEAR OPTICS, OPTICAL PROPERTIES