n-butyllithium in tetrahydrofuran; hexane; benzene n-BuLi in hexane was added to a stirred soln. of Cp2SiMe2 in THF at 0°C, stirred at 25°C for 2 h, a suspn. of ZrCl4 in THF-benzene was added dropwise at 0°C, stirred at 25°C for 2 h (Ar atm.);; evapd., extd. with CHCl3, cooled to -20°C; elem. anal.;;

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