following test methods astm d 1238 condition e measured at 190 u00b0 c and reported as grams per 10 minutes activity values are normalized values based upon the grams of polymer produced per mmol of hafnium or zirconium in the catalyst per hour per 100 psi of ethylene polymerization pressure method a cross linked polystyrene column pore size sequence 1 column less than 1000 u00e5 3 columns of mixed 500 to 5 u00d7 10 7 u00e5 1 2 4 trichlorobenzene solvent at 140 u00b0 c with refractive index detection preparation c 5 ch 3 5 c 2 b 9 h 11 zr ch 3 a solution of 3 50 g 12 9 mmol of c 5 ch 3 5 zr ch 3 3 in 50 ml of toluene was prepared and cooled to 78 u00b0 c under a nitrogen atmosphere a solution of 1 75 g 13 0 mmol of c 2 b 9 h 13 in 40 ml of toluene was added to the precooled solution by cannula and the reaction mixture was warmed to ambient temperature gas evolution ch 4 was observed an an orange yellow solid precipitated from solution the reaction mixture was stirred for two hours at 23 u00b0 c the solid precipitate was collected by filtration washed three times with 30 ml of hexane and dried under high vacuum for 12 hours the product weighed 4 51 g representing a 94 0 yield analysis calculated for c 13 h 29 b 9 zr c 41 76 h 7 82 zr 24 40 found c 42 06 h 7 62 zr 24 74 preparation c 5 ch 3 5 c 2 b 9 h 11 hf ch 3 a solution of 3 2 g 8 93 mmol of c 5 ch 3.