PHOTOCHEMICAL-REACTION OF W(CO)(6) WITH SNCL4 .2. SYNTHESIS AND X-RAYSTRUCTURE OF TETRACHLOROBIS(TRIPHENYLPHOSPHINE OXIDE)TUNGSTEN(IV), [WCL4(OPPH(3))(2)]

The crystal structure of [WCl4(OPPh(3))(2)] (1), formed in the photoch emical reaction of W(CO)(6) with SnCl4 in the presence of triphenylpho sphine, has been determined by the single-crystal X-ray diffraction me thod. The compound crystallizes in the monoclinic space group C2/c, wi th a = 14.027(3), b = 13.163(3), c = 19.621(4) Angstrom beta = 96.36(3 )degrees, Z = 4. The structure solved by heavy-atom methods has been r efined to R = 0.0466, for 3489 observed reflections. The [WCl4(OPPh(3) )(2)] molecule possesses a crystallographically imposed C-2 axis passi ng through the tungsten atom. Despite steric demands, a mutually cis a rrangement of triphenylphosphine oxide oxygens is found for [WCl4(OPPh (3))(2)], while there is a slight lengthening of the W-Cl bonds trans to the oxygen atoms.