Synthesis and structure of ReO(PMe3)(CH2SiMe3)3 and reaction with carbon monoxide

Article abstract of DOI:10.1021/om00154a001

The reactive d² square-pyramidal complex ReO(PMe₃) (CH₂SiMe₃)₃ has been prepared by the addition of 3 equiv of Me₃SiCH₂MgCl to ReO(OEt)Cl₂(py)₂ in the presence of PMe₃ (63% yield) and by the reaction of an excess of PMe₃ with Re₂O₃(CH₂SiMe₃)₆ (86% yield). The complex ReO(PMe₃)(CH₂SiMe₃)₃ reacts rapidly in pentane with CO to give purple ReO(PMe₃)(η²-C(O)CH₂SiMe ₃)(CH₂SiMe₃)₂ in 86% yield. An analogous pyridine complex, ReO(py)(η²-C(O)CH₂SiMe₃)(CH ₂SiMe₃)₂, is prepared by adding CO to an equilibrium mixture of Re₂O₃(CH₂SiMe₃)₆ + py = ReO(py)(CH₂SiMe₃)₃ + ReO₂(CH₂SiMe₃)₃. The complex Re₂O₃(CH₂SiMe₃)₆ also reacts with O₂, DMSO, or pyridine N-oxide to yield the yellow oil ReO₂(CH₂SiMe₃)₃, which is proposed to have a trigonal-bipyramidal geometry with the oxo ligands in the equatorial plane. Photolysis of ReO₂(CH₂SiMe₃)₃ in hydrocarbon solvents gives the d¹-d¹ dimer Re₂O₄(CH₂SiMe₃)₄ as a dark yellow oil. Crystal data for ReO(PMe₃)(CH₂SiMe₃)₃ at -161°C: a = 12.090 (3) A?, b = 20.288 (7) A?, c = 19.950 (6) A?, Z = 8, d_calcd = 1.466 g cm^-3, and space group Pbca.