Me3SiSiMe3; MeLi in tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide -78°C; elem. anal.;

hexamethyl-silane; methyllithium in tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide; diethyl ether N2-atmosphere; addn. of MeLi (ether) to soln. of disilane (HMPA) at 0°C, stirring for 15 min, addn. of THF, cooling (-78°C), addn.of soln. of Co-complex (THF), warming to 0°C for 1 h; pouring into pentane, washing (H2O), drying (MgSO4), evapn., chromy. (SiO2, CH2Cl2, 5percent MeOH in CH2Cl2), evapn., recrystn. (CH2Cl2:hexane); elem.anal.;