Synthesis of a New Tetrakis(hydrosulfido) Diiridium Complex and Its Conversion into Homo- and Heterometallic Sulfido−Hydrosulfido Clusters

The diiridium tris(hydrosulfido) complex [Cp*Ir(μ2-SH)3IrCp*]Cl (2; Cp* = η5-C5Me5) reacted with [NEt4][SH] at room temperature for 3 h to afford the tetrakis(hydrosulfido) complex [Cp*Ir(SH)(μ2-SH)2IrCp*(SH)] (3). Complex 3 dissolved in benzene is thermally unstable and was converted into the triiridium sulfido−hydrosulfido cluster [(Cp*Ir)3(μ3-S)(μ2-S)(μ2-SH)2] (4) at 50 °C. The related triiridium cluster [(Cp*Ir)3(μ3-S)(μ2-SH)3]Cl (6) was obtained from either the reaction of 3 with 0.5 equiv of [(Cp*IrCl)2(μ2-H)2] or treatment of 2 with an equimolar amount of NEt3. Furthermore, reaction of 3 with 2 equiv of [Pd(PPh3)4] or a [Pd(dba)2]−PPh3 (dba = dibenzalacetone) mixture gave the Ir2Pd2 mixed-metal sulfido−hydrosulfido cluster [(Cp*Ir)2(SH)(μ3-S)2{Pd(PPh3)}2(μ2-SH)] (8). X-ray analyses were undertaken to determine the detailed structures of 3, 4, 6, and 8.