Synthesis of 2-(diphenylphosphino)phenolato and 2-(diphenylphosphinomethyl)-4-methylphenolato complexes of titanium and zirconium. X-ray characterization of [( η5-C 5H5) 2ZrCl(OC 6H4PPh2] and [( η5-C 5H 5) 2 Zr(OC 6H 4PPh 2) 2

Abstract

Complexes [(C 5H 5) 2MCl 2] (MTi, Zr) react with the 2-(diphenyl-phosphino)phenol HO(C 6H 4)PPh 2 in the presence of imidazole to give the corresponding complexes [Cp 2ZrCl(OC 6H 4PPh 2)], 1 and [Cp 2M(OC 6H 4PPh 2) 2] ( 2: MTi; 3: MZr). Under the same experimental conditions, the bulkier ligand 2-(diphenylphosphinomethyl)-4-methylphenol HO(C 6H 3-(CH 3)CH 2PPh 2 failed to react with [Cp 2MCl 2] (Ti or Zr) but with Cp 2Zr(CH 3) 2 gives the methyl complex [Cp 2Zr(CH 3){O(C 6H 3)(CH 3)CH 2PPh 2}], 4 and [Cp 2Zr[O(C 6H 3)(CH 3)CH 2PPh 2] 2], 5. Compounds 1 and 3 crystallize from CH 2Cl 2 solution, and their structures have been determined. The relatively short ZrO bond distance of 1.979(7) Å, and the ZrOC bond angle of 160.2(5)°, 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( 31 P) = 14.6 G ). Preliminary data indicate that 3 acts as a diphosphine ligand upon reaction with [{Rh(CO) 2Cl} 2].