-DIPHENYLPHOSPHINOYL-2'-HYDROXY-1,1'-BINAPHTHALENE AND -DIPHENYLPHOSPHINOYL-2'-HYDROXY-1,1'-BINAPHTHALENE - VERSATILE CHIRAL BIDENTATE LIGANDS

The homochiral compounds (R)- and diphenylphosphinoyl-2'-hydroxy-1,1'- binaphthalene, (R)- and (S)-Hbinappo, react with TiCl4 or ZrCl4 to pro duce complexes of bidentate binappo(-), [MCl(2)(binappo)(2)] (M = Ti-I V or Zr-IV). VCl3, FeCl3 and MoO2Cl2 also react with Hbinappo, but req uire the presence of a base to produce [M(binappo)(3)] (M = V-III or F e-III) or [MoO2(binappo)(2)]. The complex [MoO2(acac)(2)] (acac = acet ylacetonate) reacts with Hbinappo to produce [MoO2(acac)(binappo)]. Th e vanadium(III) tris(chelate) complexes are readily oxidised in air to [VO(binappo)(2)]. All of these complexes have been characterised by m icroanalytical, infrared, and, where appropriate, NMR, electronic and CD spectroscopic techniques. (S)-Hbinappo, [ZrCl2{(S)-binappo}(2)], [V {(S)-binappo}(3)] and [VO{(S)-binappo}(2)] have also been characterise d by single-crystal X-ray techniques. In all of the complexes the liga nds are co-ordinated through their phenolate and phosphinoyl oxygen at oms forming eight-membered chelate rings. The tris-chelate complexes f orm stereospecifically, (S)-binappo giving the Lambda isomer exclusive ly, and the (R)-form producing Delta-[M(binappo)(3)]. Although each of the [M(binappo)(3)] species are necessarily sterically crowded, littl e M-O bond elongation is observed in the single-crystal X-ray structur e of [V{(S)binappo}(3)]. Initial attempts at achieving asymmetric indu ction in Ti-IV- and VOIV-based oxidations of prochiral sulfides in the presence of these ligands are also presented, but observed enantiomer ic excesses are generally <10%.