Synthesis and structure of tetrachloro[4-tert-butyl-2-(diphenylphosphanyl-kappa P-methyl)phenolato-kappa O]tantalum(V), a novel Ta-V complex with a chelating aryloxy phosphane ligand

4-tert-Butyl-2-(diphenylphosphanylmethyl)anisol (1) is prepared from 2-chlo rmethyl-4-tert-butylanisol and potassium diphenylphosphide in very good yie lds as a novel oxygen-phosphorus compound with potentially hemilabile ligan d properties. Compound 1 reacts with tantalum pentachloride under cleavage of methylchloride revealing the complex tetrachloro[4-tert-butyl-2-(dipheny lphosphanyl-kappa P-methyl)phenolato-kappa O]tantalum (V) (2) with a distor ted octahedrally coordinated tantalum atom and a chelating aryloxy phosphan e ligand. Complex 2 crystallizes in the tetragonal, chiral space group P4(1 )2(1)2 with a = 11.719(5), c = 37.95(5) Angstrom, V = 5171(7) Angstrom(3), Z = 8. P-31. NMR spectroscopic studies of 2 establish the coordination of t he phosphane unit to the Ta-V center in solution.