Synthesis of 2-(diphenylphosphino)phenolato- and 2-(diphenylphosphinomethyl)4-methylphenolato complexes of titanium and zirconium. X-ray characterization of 5-C5H5)2ZrCl(OC6H4PPh2)> and 5-C5H5)2Zr(OC6H4PPh2)2>

Article abstract of DOI:10.1016/0022-328X(94)05197-J

Complexes <(C5H5)2MCl2> (M = Ti, Zr) react with the 2-(diphenyl-phosphino)phenol HO(C6H4)PPh2 in the presence of imidazole to give the corresponding complexes , 1 and (2: M = Ti; 3: M = Zr).Under the same experimental conditions, the bulkier ligand 2-(diphenylphosphinomethyl)-4-methylphenol HO(C6H3)(CH3)CH2PPh2 failed to react with (Ti or Zr) but with Cp2Zr(CH3)2 gives the methyl complex >, 4 and 2>, 5.Compounds 1 and 3 crystallize from CH2Cl2 solution, and their structures have been determined.The relatively short Zr-O bond distance of 1.979(7) Angstroem, and the Zr-O-C bond angle of 160.2(5) deg, in one phenoxy ligand of 3 suggest significant double bonding between Zr and O atoms.Chemical reduction of 1 with Na/Hg gives the expected cyclic P-metallated Zr^III species characterized by EPR (g = 1.976; a(31P) = 14.6 G.).Preliminary data indicate that 3 acts as a diphosphine ligand upon reaction with<2>. Keywords: Titanium; Zirconium; X-ray structure; Phenolato complexes; Phosphinophenolato complexes