in tetrahydrofuran Li salt and Hf complex placed in Schlenk flask under Ar, cooled to -78°C, THF slowly introduced with stirring, suspn. gradually warmed toroom temp. for 30 min, stirred for 16 h, heated at 60°C for 18 h; crystals of (C5H5)2HfCl2 isolated by crystn. from dichloromethane;

in tetrahydrofuran T=60°C; 24 h; Inert atmosphereSchlenk technique;