Todd Graham - ((Diaryl- and Dialkylphosphino)alkyl)cyclopentadienyl Ligands and Their Use in the Preparation of Heterobinuclear Ti/Mo and Zr/Mo Complexes

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  Publication Details (including relevant citation   information):

  Todd W. Graham, Angela Llamazares, Robert McDonald,  and Martin Cowie

  Organometallics, 1999, 18 (17), 3490


  The syntheses of a series of bifunctional ligands, in which a   cyclopentadienyl and a phosphine group are linked by either a   CH2 or a C2H4 fragment   (-C5H4(CH2)nPR2;   n = 1, 2; R = Me, Ph), are reported, as is that of the   related ligand,   Li2[Me2C(C5H3CMe2PPh2)2],   in which both substituted cyclopentadienyl rings are linked by   the CMe2 group. The metallocene dichloride complexes   Cp‘2MCl2 (M = Ti, Zr; Cp‘2 =   2C5H4(CH2)nPPh2  (n = 1, 2),   Me2C((C5H3)C(Me)2PPh2)2)   have also been prepared, and the X-ray structure of   (η5-C5H4(CH2)2PPh2)2ZrCl2  (7) has been determined. This complex has the   pendent phosphinoalkyl arms close to eclipsed on the two   C5H4 groups and bisecting the   ZrCl2 angle, but bent in opposite directions away from   the ZrCl2 plane. Reaction of 7 and   its Ti analogue with (COD)Mo(CO)4 yields the   heterobinuclear complexes   [(μ-η51-C5H4(CH2)2PPh2)2MCl2Mo(CO)4]    (M = Ti, Zr). Structure determinations of these bimetallic   complexes  show the expected cis arrangement of phosphine   moieties at Mo, M−Mo  separations of 6.895 Å (M = Ti) and   6.945 Å (M = Zr), and MCl2 moieties aimed at right   angles to the M−Mo vectors.

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