C5H4Me2; BuLi; HCl in hexane; water; toluene stirring (room temp., 1 h, vac.), ZrCl4 addn., refluxing (Ar-atmosphere), HCl (aq) addn.; filtering, recrystn. (toluene);

methylaluminoxane in benzene-d6 under Ar, standard Schlenk techniques; solid dichloride Zr complex mixedwith 1 equiv. of Cp2ZrClMe; dissolved in benzene-d6; a minute amt. of s olid methylaluminoxane added; equil. reached within several min; not isolated; monitored by (1)H NMR spectra;