n-butyllithium in diethyl ether; hexane 2 M C4H9Li in hexane added dropwise at -78°C to soln. of (C13H9)C(C6H5)2(C5H5) (2.2 mmol) in ether, stirred overnight, ZrCl4 (2.2 mmol) added, stirred for 8 h at room temp.; evapd. to dryness, recrystd. (toluene);