PREPARATION OF DICYCLOPENTADIENYLDIPHENYLPHOSPHINE-HYDRIDOMOLYBDENIUM(IV) CHLORIDE AND ITS REACTIONS WITH ELECTRON POOR ALKYNES RCCR' (R=R'=CF3, CO2Me; R=H, R'=CN). FORMARION OF MOLYBDAPHOSPHACYCLOBUTANES AND X-RAY STRUCTURE OF 5-C5H5)2MoCH(CF3)PPh2>Cl*H2O

Article abstract of DOI:10.1016/S0022-328X(00)99363-X

Reactions of PPh2Cl with (η⁵-C5H5)2MH2 (M=Mo, W) in toluene give the ionic complexes <(η⁵-C5H5)2MH(PPh2H)>Cl.The reactions of the molibdenum derivative with electron poor alkynes RC<*>CR' (R=R'=CF3 (hfb), CO2Me (dmad); R=H, R'=CN (mca)) were studied, and insertions of the alkynes into the Mo-H bond, leading to either the ionic complexes <(η⁵-C5H5)2Mo(PPh2H)(?-CR=CHR')>⁺ (hfb, dmad, mca) or the molecular species <(η⁵-C5H5)2MoCl(?-CR'=CHR)> (dmad, mca), were observed.In the case of hfb and dmad the cationic metallaphosphacyclobutanes <(η⁵-C5H5)2MoCHRCHRPPh2>⁺ were formed.An X-ray diffraction study of the latter complex, derived from hfb, revealed an ionic structure with the presence of water of hydration in the centrosymmetric triclinic cell (P1, a 7.919(8), b 9.689(7), c 16.613(11) Angstroem, α 81.52(5), β 80.82(5), γ 82.44(5) deg).The water molecules and the chloride ligands are involved in hydrogen bonding.The Mo-P bond length is 2.487(1) Angstroem, that of Mo-C(sp³) is 2.299(3) Angstroem, and the C-Mo-P angle is 63.8(1) deg.