Heterobimetallic Cluster-Based Coordination Polymers: Assembly, Structures and Third-Order Nonlinear Optical Properties.

Reactions of (NH4 )2 WS4 with CuCN, CuCN/1,2-bis(4-pyridyl)propane (bppa) or [Cu(MeCN)4 ]PF6 /bppa under different reaction conditions afforded a set of two- or three-dimensional W/Cu/S cluster-based coordination polymers including {[Et4 N]2 [WS4 Cu4 (μ-CN)2 (μ-I)2 ]}n (1), [WS4 Cu4 (μ-CN)2 (bppa)2 ]n (2) and {[WS4 Cu4 (bppa)4 ](PF6 )2 }n (3), respectively. Compound 2 can be readily formed from reaction of 1 with bppa under solvothermal conditions. Compounds 1 and 2 feature two-dimensional networks with a "sql" topology, while 3 possesses a two-fold interpenetrated three-dimensional net with a rare "reo" topology. Compounds 1-3 in DMF exhibited different third-order nonlinear optical responses, and they all showed a reverse saturable absorption while 2 held a strong self-focusing effect.