Complexes of osmium with polytertiary phosphines

Abstract

Complexes of Osmium(II) and Osmium(III) with the polytertiary phosphines, C₆H₅P[CH₂CH₂P(C₆H₅)₂]₂; (triphos), (C₆H₅)₂PCH₂CH₂P(C₆H₅)CH₂CH₂P(C₆H₅)CH₂CH₂P(C₆H₅)₂ (tetraphos-1), P[CH₂CH₂P(C₆H₅)₂]₃; (tetraphos-2) and C₆H₅{CH₂P[CH₂CH₂P(C₆H₅)₂]₂}₂; (TDDX) are described. Osmium trichloride reacts with triphos, tetraphos-1, and tetraphos-2 in benzene methanol mixture at reflux temperature to give the complexes OsCl₃ (triphos), [OsCl₃(S)]₂ (tetraphos-1) and OsCl₃(tetraphos-2) respectively. The hexatertiary phosphine TDDX, formed only polynuclear complexes with osmium and attempts to prepare mononuclear complexes failed. The ligand TDDX reacted with either osmium trichloride or ammonium hexachloro osmate(IV) in boiling ethanol to give the diamagnetic trinuclear complex Os₃Cl₆(TDDX) and paramagnetic complexes of the type Os₂X₆(TDDX) where X=Cl or Br). The proton NMR spectra of the complexes are discussed and used along with the IR data to assign configurations.