Sulfur–carbon bond cleavage in reactions of rhenium(V) complexes of NS3 ligands with tertiary phosphines: crystal and molecular structures of [ReO(SCH2CH2NCOCH2S)(PMe2Ph)] and [ReO(SCMe2CH2NCOCH2SCH2CH2S)(PMePh2)]

Abstract

The neutral rhenium(V) oxo complex [ReO{S(CH₂)₂SCH₂CONCH₂S}] reacted with tertiary phosphines PMe₂Ph or PMePh₂ to give the rhenium(V) species [ReO(NS₂)(PR′₃)] (PR′₃ = PMe₂Ph 1, or PMePh₂ 2), with loss of a SCH₂CH₂ group. The introduction of dimethyl substituents at C(6) of the tetradentate ligand prevents C–S bond cleavage and [ReO(NS₂)(PR′₃)] type complexes were formed (PR′₃ = PMe₂Ph 3, or PMePh₂ 4). The crystal and molecular structures of complexes 1 and 4 have been determined. Complex 1 is essentially square pyramidal with an apical oxo group and a PNS₂ donor set in the basal sites. The geometry of 4 is essentially octahedral with a thiolate sulfur of the NS₃ ligand trans to the oxo group.