PHOSPHORUS YLIDES AS HARD DONOR LIGANDS - SYNTHESIS AND CHARACTERIZATION OF MCL4(YLIDE-O)(THF) (M = TI, ZR, HF, YLIDE = (ACETYLMETHYLENE)TRIPHENYLPHOSPHORANE, (BENZOYLMETHYLENE)TRIPHENYLPHOSPHORANE) - MOLECULAR-STRUCTURE OF TRANS-((ACETYLMETHYLENE)TRIPHENYLPHOSPHORANE-O)(TETRAHYDROFURAN)TETRACHLOROTITANIUM-(IV)-TETRAHYDROFURAN

The reactions between oxophilic group 4 metal chlorides and the ambidentate α-keto ylides (acetylmethylene)triphenylphosphorane (APPY) and (benzoylmethylene)triphenylphosphorane (BPPY), in THF, lead to the formation of O-bound transition-metal-ylide complexes. The compounds were characterized by proton, carbon-13, and phosphorus-31 NMR spectroscopy and by infrared spectroscopy. Crystallographic characterization of trans-[TiCl4(APPY-O)(THF)]·THF (4) revealed that the ylide adopts the cisoid conformation in the solid state. 4 crystallizes in the monoclinic space group P21/n in a unit cell of dimensions a = 15.735 (5) Å,b = 9.818 (3) Å, c = 19.992 (5) Å, β = 105.17 (2)°, and V= 2981 (1) Å3,with RF = 0.0554 (RwF = 0.0554) for 286 parameters and 2251 observed reflections having Fo > 5σ(Fo). The potential of these complexes for forming O-bound, orthometalated species is discussed. © 1990, American Chemical Society. All rights reserved.