Synthesis, Crystal Structure and Third‐order Nonlinear Optical Properties of Nest‐shaped Cluster [CuBr(bpy) 2 ] [MoOS 3 Cu 3 ‐Br 2 (bpy)]

Nest‐shaped cluster [CuBr(bpy) 2 ][MoOS 3 Cu3Br 2 (bpy)] was synthesized by the treatment of (NH 4 ) 2 MOO 2 S 2 , CuBr and Et 4 NBr with bpy (2,2′‐bipyridyl) in CH 3 CN. Its structure has been characterized by X‐ray diffraction; monoclinic, space group P 2 1 / n ‐ with a = l.0092(4), b = 2.6347(7), c = 1.4087(3) nm, β = 91.744(9)°, V = 3.7438 nm 3 , Z=4, and final R = 0.051, R w = 0.053. It consists of two parts: nest‐shaped structural unit [MoOS 3 Cu 3 Br 2 (bpy)] and complex ion [CuBr(bpy) 2 ] + . We determined its third‐order nonlinear optical (NLO) properties with a 7‐ns pulsed laser at 532 nm. The duster exhibits strong NLO refractive behavior, its third‐order susceptibility χ (3) was calculated to be 2.7 · 10 −11 esu in a 7.8 · 10 −4 g/cm 3 DMF solution. The value is comparable to those of inorganic dusters.