in Petroleum ether dropwise addn. of soln. of TiCl4 in petroleum ether (40-60°C) to soln. of 1-trialkoxysilyl 2-phenylhydrazine (equimolar amts., 0 to -10°C, under dry nitrogen), ppt. filtered in a cold atm. of dry N2; washed, dried under reduced pressure; elem. anal.;

in Petroleum ether dropwise addn. of soln. of SnCl4 in petroleum ether (40-60°C) to soln. of 1-trialkoxysilyl 2-phenylhydrazine (equimolar amts., 0 to -10°C, under dry nitrogen), ppt. filtered in a cold atm. of dry N2; washed, dried under reduced pressure; elem. anal.;