((Diaryl- and dialkylphosphino)alkyl)cyclopentadienyl ligands and their use in the preparation of heterobinuclear Ti/Mo and Zr/Mo complexes

The syntheses of a series of bifunctional ligands, in which a cyclopentadie nyl and a phosphine group are linked by either a CH2 or a C2H4 fragment ((- CH4)-H-5(CH2)(n)PR2; n =1, 2; R = Me, Ph), are reported, as is that of the related ligand, Li-2[Me2C(C5H3CMe2PPh2)(2)], in which both substituted cycl opentadienyl rings are linked by the CMe2 group. The metallocene dichloride complexes Cp(2)(')Mcl(2) (M = Ti, Zr; Cp-2' = 2C(5)H(4)(CB2)(n)PPh2 (n = 1 , 2), Me2C((C5H3)C(Me)(2)PPh2)(2)) have also been prepared, and the X-ray s tructure of (eta(5)-C5H4(CH2)(2)PPh2)(2)ZrCl2 (7) has been determined. This complex has the pendent phosphinoalkyl arms close to eclipsed on the two C 5H4 groups and bisecting the ZrCl2 angle, but bent in opposite directions a way from the ZrCl2 plane. Reaction of 7 and its Ti analogue with (COD)Mo(CO )(4) yields the heterobinuclear complexes [(mu-eta(5):eta(1)-C5H4(CH2)(2)PP h2)(2)MCl2Mo(CO)(4)] (M = Ti, Zr). Structure determinations of these bimeta llic complexes show the expected cis arrangement of phosphine moieties at M o, M-Mo separations of 6.895 Angstrom (M = Ti) and 6.945 Angstrom (M = Zr), and MCl2 moieties aimed at right angles to the M-Mo vectors.