in 1,4-dioxane; diethyl ether soln. of Me2Mg in Et2O/dioxane was added to soln. of Zr complex in Et2O;mixt. was stirred overnight; solvent removed (vac.); dissolved in C6H6; filtered; washed (C6H6); filtrate evapd. (vac.); washed (hexanes); dried (vac.);