Neutral '3+1' mixed-ligand oxorhenium(V) complexes with tridentate [S,N,S] chelates and aminoalkanethiols: synthesis, characterization and structure determination

'3+1' Oxorhenium(v) complexes [ReO(SN(R')S)(SR)] (R' = Me, Et, Pr or Bu; SR = aminoalkane thiolate) have been synthesized by ligand exchange at trans-trichloromonooxo-bis(triphenylphosphine)rhenium(v) with a mixture of HSN(R')SH and RSH in alkaline methanolic solution. The complexes were purified by column chromatography and characterized by elemental analysis, mass and IR spectroscopy and for selected compounds by 1H NMR spectroscopy. The structures of those complexes have been determined by X-ray diffraction analysis and revealed a change in the co-ordination geometry from square pyramidal to trigonal bipyramidal, depending on the chelating (SN(R')S) moiety. The alkyl group (R') was found to be arranged "syn" to the oxorhenium group.