Tris-mercaptophenylphosphine complexes of rhenium: Synthesis, reactivity and structural characterization

Abstract

The reactions of various rhenium(III) precursers with the tetradentate umbrella ligand tris-( ortho-mercaptophenyl)phosphine (PS 3 for the tri-anionic form) followed by various neutral donor ligands is the focus of this work. The addition of a solution of P(SLi) 3 in THF to [ReBr 3(THT) 3] in THF followed by the addition of excess isonitrile gives the octahedral complex [PS 3Re(CN iPr) 2]. This reaction also allows isolation of [PS 3Re(CN iPr)] which is separated from the bis-isonitrile complex via column chromatography. Both of these complexes were structurally characterized with the five-coordinate species displaying trigonal bipyramidal geometry and the six-coordinate species displaying a distorted octahedral geometry. The decomposition product [(S 2PS-SPS 2)Re] is also isolated from the chromatographic separation of the two isonitrile complexes. This neutral octahedral complex displays coordination through two phosphine and four thiolate moieties, with a non-coordinated disulfide bridge that links the remaining sulfurs. The addition of a solution of H 3PS 3 and iPr 2NEt in THF to [ReBr 3(THT) 3] followed by the addition of dimethylphenylphosphine yields [PS 3Re(PMe 2Ph) 2]. This complex, similar to the bis-isonitrile species, displays a distorted octahedral geometry. These complexes and others in the series have been fully characterized with NMR spectroscopy, infrared and mass spectrometry and elemental analyses.