NEW PIANO STOOL CIS-BIS(ORGANOHYDRAZIDO) COMPLEXES OF MOLYBDENUM - X-RAY STRUCTURE OF [(ETA(5)-C5H5)MO(NNPH2)(2)(PPH3)]-(CF3SO3)

A two-step procedure for the synthesis of cationic organometallic comp lexes containing the robust cis-{Ma(NNRPh)(2)}(2+) core (R = Me, Ph) i s reported. The reaction of silver triflate, AgOTf (OTf-= CF3SO3-), wi th an equimolar amount of [Mo(NNMePh)(2)Cl-2(PPh3)(2)] (1) or [Mo(NNPh 2)(2)Cl-2(PPh3)] (2) (in the presence of 1 equiv of PPh3) in CH2Cl2/CH 3CN yields ionic intermediates formulated as [Mo(NNRPh)(2)Cl(PPh3)(2)] +OTf-; (R = Me, [3]+OTf-; R = Ph, [4]+OTf-), which give ionic pro duct s formulated as [(eta(5)-C5H5)Mo(NNRPh)(2)(PPh3)]+OTf- (R = Me, [5]+OT f-; R = Ph, [6]+OTf-) upon reaction with excess NaCp in THF. These com pounds have been characterized by IR, UV-visible, and NMR spectroscopy and cyclic voltammetry. The molecular structure of [6]+OTf- has also been determined by X-ray diffraction.