Synthesis and Characterization of the New Cluster Complex {Mo₃S₄} with the Hemilabile Phosphine-Selenoether Ligand

The reaction of [Mo₃S₄(Tu)₈(H₂O)]Cl₄·4H₂O (Tu is thiourea) with (PhCH₂CH₂)₂-PCH₂CH₂SeC₅H₁₁) (PSe) followed by purification on a chromatographic column packed with silica gel using a saturated solution of KPF₆ in acetone as an eluent results in the formation of [Mo₃S₄Cl₃(PSe)₃]PF₆ (I) in a yield of 44%. Compound I is characterized by X-ray diffraction analysis, ¹H, ³¹P{¹H}, and ⁷⁷Se NMR spectroscopy, IR spectroscopy, UV-Vis spectroscopy, cyclic voltammetry, and electrospray ionization mass spectrometry. Several species differed in the coordination mode of three PSe ligands, which can bind to molybdenum via one (phosphorus) or two (phosphorus and selenium) donor atoms, are formed in a solution of compound I at room temperature. This behavior is not observed for the compounds similar in structure with PS ligands of an analogous type. Complex I demonstrates a higher catalytic activity than its analogue with the PS ligand in the reduction of nitrobenzene to aniline under the action of diphenylsilane.