Preparation of a bis(hydrosulfido) complex of Mo having a tetraphosphine co-ligand and its transformation into MoRh2 and MoIr2 mixed-metal sulfido clusters

Abstract

The treatment of a Mo(0) complex with a tetraphosphine co-ligand [Mo(κ⁴-P4)(Ph₂PCH₂CH₂PPh₂)] (P4 = meso-o-C₆H₄(PPhCH₂CH₂PPh₂)₂) with H₂S gas in toluene at room temperature afforded [Mo(SH)₂(κ⁴-P4)] (1), which demonstrates the first Mo(II) bis(hydrosulfido) complex. Its trigonal-prismatic structure rarely observed for Mo(II) complexes has been determined by X-ray analysis. The reactions of 1 with [RhCl(CO)₂]₂ and [IrCl(CO)₂(p-toluidine)] in the presence of NEt₃ resulted in the formation of the sulfido-bridged trinuclear clusters [Mo(κ⁴-P4)(μ₃-S)₂{Rh(CO)₂}₂] (4) and [Mo(κ⁴-P4)(μ₃-S)₂{Ir(CO)₂}₂] (5), respectively. The X-ray diffraction study has disclosed that the MoRh₂ cluster 4 in the solid state exists in two isomeric forms arising from the different orientation of P4 to the trigonal-prismatic Mo center, whereas the crystals of the Ir analogue 5 contains the molecules corresponding to only one of the two isomers observed for 4. The fluxional features of 1, 4, and 5 in solution have been confirmed by VT NMR studies.