in toluene byproducts: LiCl; HfCl4 and LiC5(CH3)5 in toluene is refluxed for 2 d under Ar; solvent is removed in vac.;; sublimation at 105°C, 0.0001 torr; elem. anal.;

H2 in not given byproducts: HP(C(CH3)3)2; High Pressure; react. of Hf complex with H2 (3 atm) for several weeks;

in n-heptane Addn. of C5(CH3)5Si(CH3)3 to suspension of HfCl4 in heptane (N2), slowly warming (60 °C), stirring (4 h), cooling.; Filtration, washed (hexane), dried (vacuum), elem. anal.;

in o-xylene=o-xylol stirring at room temp. for 12 h; after filtration the solid was washed with n-pentane, sublimation, elem. anal.;

in n-heptane by a react. of Si-contg. compd. (18.2 mmol) and HfCl4 (17.4 mmol) in heptane; stirring at 80°C for 6 h; according to G. H. Linnas et al. J. Organomet. Chem., 1988, 340, 37;

HCl in benzene An excess of HCl reacts with a suspension of tetramer Hf-complex in benzene at room temp. under N2.; The bright yellow suspension turnes off-white, after 0.5 h the gases are collected and passed through a liquid-N2-cooled trap, removal of the volatiles, residue is investigated by IR.;

in xylene byproducts: LiCl;