Triorganoantimony(V) diorganophosphinates. Crystal and molecular structure of (diphenylphosphinato)(hydroxo)trimethylantimony(V), exhibiting a polymeric chain supramolecular self-assembly through hydrogen bonds

Abstract

The reaction between R 3SbCl 2 (R = Me, Ph) and R′ 2PO 2Na (R′ = Me, Ph) afforded R 3Sb(O 2PR′ 2) 2 derivatives, which were investigated by IR and multinuclear ( 1H, 13C, 31P) NMR spectroscopy. Attempts to grow crystals of Me 3Sb(O 2PPh 2) 2 led to colorless needles identified by X-ray diffractometry as Me 3Sb(OH) [O(O)PPh 2], produced by partial hydrolysis. Coordination around the central metal atom is distorted trigonal bipyramidal with carbon atoms of the SbMe 3 unit in equatorial positions and two oxygen atoms occupying the axial positions [OSbO 175.7(1)°]. The two antimony-oxygen distances are significantly different [SbO(H) 1.967(3) Å, SbO(P) 2.235(2) Å], as are the phosphorus-oxygen bond lengths in the basically monodentate diphenylphosphinato ligand [PO 1.528(3) Å, PO 1.490(3) Å]. The molecules are associated into polymeric chains through intermolecular hydrogen bonds between hydrogen of the hydroxo group and oxygen double bonded to phosphorus.