Synthesis, crystal structure and non-linear optical properties of two new cluster compounds, [MoCu3OS3(PPh3)3{S2P(OBu)2}] and [MoAg3S4(PPh3)3{S2P(OBui)2}]

Abstract

Two novel O,O′-dialkyl dithiophosphate-containing Group 11–Group 16 sulfido clusters, [MoCu₃OS₃(PPh₃)₃{S₂P(OBu)₂}]1 and [MoAg₃S₄(PPh₃)₃{S₂P(OBuⁱ)₂}]2, have been synthesised through reactions of [NEt₄]₂[MoOS₃] with Cu[S₂P(OBu)₂] and [NEt₄]₂[MoS₄] with Ag[S₂P(OBuⁱ)₂] respectively in dichloromethane and in the presence of PPh₃. The clusters crystallise in orthorhombic and triclinic forms respectively. The X-ray crystallographic structure determinations show that both clusters have a partial open cubane-like structure. The dithiophosphate ligands adopt a triply bridging role, employing two sulfur atoms to co-ordinate to the three Group 11 metal (M) atoms: one sulfur atom binds to one M atom, the other to two other M atoms. The clusters are soluble in common organic solvents and exhibit both non-linear absorption and non-linear refraction (self defocusing). Cluster 2 also exhibits a sizeable optical limiting effect.