SYNTHESIS AND CHARACTERIZATION OF 2 NEW MOLYBDENUM(0) SIGMA-ARYL COMPLEXES OF THE TYPE [N(PPH(3))(2)][MO(C6F5)L(CO)(2)(P(OME)(3))(2)] - X-RAY CRYSTAL-STRUCTURE OF BIS(TRIPHENYLPHOSPHINE)IMINIUM PENTAFLUOROPHENYL(MER-TRICARBONYL) TRANS-BIS(TRIMETHYLPHOSPHITE)MOLYBDATE(0)

The complex [cis-mer-Mo(C6F5)(CO)(2){P(OMe)(3)}(3)](-) reacts with the pi-acid ligands CO and (t)BuNC to yield the substitution products [Mo (C6F5)L(CO)(2){P(OMe)(3)}(2)](-), both isolated as the N(PPh(3))(2)(+) salts. Both new complexes have been fully characterized by IR, H-1 an d P-31 NMR, and elemental analysis. The electrochemistry of all three complexes has also been examined. The structure of [N(PPh(3))(2)][mer- trans-Mo(C6F5)(CO)(3) {P(OMe)(3)}(2)] has been determined by X-ray cry stallography. The compound displays essentially octahedral geometry ab out the molybdenum atom. Averaged important bond distances and angles are: Mo-C(O) = 1.99(3); C=O = 1.18(1); Mo-P = 2.418(1); P-O(C) = 1.614 (9); O-C = 1.440(11); N-P = 1.578(9); P-C(ring) = 1.805(4) Angstrom; a nd Mo-P-O = 119(4)degrees; P-O-C = 120.9(7)degrees; N-P-C(ring) = 111( 2)degrees.