31P NMR and X-ray crystallographic study of atropisomerism in cis-tetracarbonylmolybdenum(0) and cis-dichloroplatinum(II) complexes of (±)-6,6′-[[1,1′-Biphenyl]-2,2′-diylbis(oxy)] bis(dibenzo[d,f]-[1,3,2]dioxaphosphepin) and (±)-6,6′-[[1,1′-Binaphthyl]-2,2′-diylbis(oxy)] bis(dibenzo[d,f][1,3,2]dioxaphosphepin) ligands

Academic Article

Abstract

  • Both cis-tetracarbonylmolybdenum(0) and cis-dichloroplatinum(II) complexes of {(±)-6,6′-[[1,1′-biphenyl]-2,2′-diylbis(oxy)] bis(dibenzo [d,f][1,3,2]dioxaphosphepin)}, 1, and {(±)-6,6′-[[1,1′-binaphthyl]-2,2′-diylbis(oxy)] bis(dibenzo[d,f][1,3,2]dioxaphosphepin)}, 2, have been prepared. Atropisomerism of the ligands in these complexes has been investigated by variable-temperature 31P{1H} NMR spectroscopy. These studies demonstrate that all three diastereomers are present in solutions of the cis-tetracarbonylmolybdenum(0) complexes of both ligands in the slow exchange region, although the distribution of the diastereomers is strongly dependent on the nature of the ligand. The conformations proposed for the major complexes in solution are consistent with the solid-state conformations of the complexes, as determined by X-ray crystallography. Only two species are present in solutions of the cis-dichloroplatinum(II) complexes, and surprisingly, both appear to have the R*R*S*(S*S*R*) configuration. The different conformations of the R*R*S*(S*S*R*) disatereomers may arise from different interplanar angles of the biaryl group in the nine-membered chelate ring. © 1999 American Chemical Society.
  • Published In

  • Organometallics  Journal
  • Author List

  • Hariharasarma M; Lake CH; Watkins CL; Gray GM
  • Start Page

  • 2593
  • End Page

  • 2600
  • Volume

  • 18
  • Issue

  • 14