Water-controlled reactions selectivity of the ReOCl3(OPPh3)(SMe2) synthon with a hydrophosphorane ligand

The reaction of the hydrospirophosphorane HP(OCMe2CMe2O)2 ligand or the five-membered cyclic hydrogen phosphonate HP(O)(OCMe2CMe2O) ligand with the ReOCl3(OPPh3)(SMe2) precursor under controlled reaction conditions led to the isolation of dimeric oxo-rhenium(V) complexes containing P(O)(OCMe2CMe2O)− moieties, represented by [ReOCl2{μ-OP(OCMe2CMe2O)}3ReOCl(OPPh3)] (1) and [ReOCl2(SMe2){μ-OP(OCMe2CMe2O)}]2 (2). The chemical composition of these complexes was established by means of NMR, IR spectroscopic methods, and based on analytical data. The relative stereochemistry of 1 and 2 was unambiguously determined by single X-ray diffraction studies. The crystal structure of 1 comprises two crystallographically independent molecules in an asymmetric unit and co-crystallised molecules of both dichloromethane and acetonitrile. Two different six-coordinated monomeric subunits, ReOCl2 and ReOCl(OPPh3), connected by three phosphonate bridges, build up the dinuclear complex 1. It exhibits an uncommon feature, a cis disposition of the triphenylphosphine oxide molecule relative to the terminal Redouble bond; length as m-dashO bond. The crystal structure of 2 includes four molecules, in which two equivalent rhenium subunits ReOCl2(SMe2) are linked by two P(O)(OCMe2CMe2O)− bridges.