in deuterated toluene using Schlenk techniques; mixing of solns. of B(C6F5)3 and Al2Me6 in toluene-d8 in NMR tube for 10 min, addn. of soln. of ZrMe2(C5Me5)2 in toluene-d8 at 20°C with ratio B(C6F5)3, Al2Me6 and (C5Me5)2ZrMe2 1:2:1; monitoring by NMR;
