Synthesis of .MU.-Oxo Complexes of Group 4 Bridged-Metallocenes: A Convenient Separation of meso and racemo Isomers.

Treatment of a 1:1 mixture of meso and racemo isomers of the group 4 bridged-metallocene dichlorides, R(2)A(R'nC5H4-n)(2)MCl2 (R-2 = Me-2, (CH2)(4); A= Si, Ge; R'= Me, t-Bu; M = Zr, Hf; n = 1-3) with 0.5 equivalent of amine afforded an mu-oxo complex arising from the meso isomer and left the racemo isomer intact, providing a convenient method of separation of the isomeric mixture.