lithium in tetrahydrofuran under Ar; Li wire, Me3SiCl and THF cooled to -78°C, slow addn. GeCl4/THF over 1.5h, suspn. turned dark red-brown immediately and Li wire clean, mixt. slowly warmed to room temp., stirred overnight, mixt. turned brown with black ppt., kept 25h; Li turned black after all Me3SiCl consumed (NMR-spect.), filtered, addn. 10percent HCl giving a voluminous brown ppt. (removed by filtration), extn. (ether), dried, evapn., crystn. (acetonitrile);

in hexane Ar-atmosphere; stirring at -78°C for 9 h, warming to room temp., stirring for 15 h; solvent removal (vac.), stirring with pentane for 1 h, filtration, evapn., repeated recrystn.;

HCl in diethyl ether Ar-atmosphere; room temp., 5 days; addn. of 10percent HCl, extn. (ether); product mixt. not sepd., detd. by (1)H-NMR spectroscopy;

in diethyl ether under Ar; Et2O soln. of Ge deriv., excess of chlorosilane and nonadecan (internal standard) stirred at room temp. for 4 d; gas chromy.;

in hexane Ar-atmosphere; 2 equiv. of Li-compd., -78°C; mixt. with tetragermane educt not sepd., detd. by (1)H-NMR spectroscopy;

in hexane Ar-atmosphere; stirring stoich. amts. at -78°C for 9 h, warming to room temp., stirring for 15 h; solvent removal (vac.), stirring with pentane for 1 h, filtration, concn. of filtrate, crystn. (-78°C, 6 h); further crop on concn. of filtrate; elem. anal.;

1: diethyl ether 2: diethyl ether View Scheme

in hexane Ar-atmosphere; dropwise addn. of GeCl4 to 2 equiv. of Li-compd. (-78°C, stirring (-78°C, 12 h), slow warming to ambient temp., stirring (36 h); product mixt. not sepd., detd. by (1)H-NMR spectroscopy;

in hexane Ar-atmosphere; stirring stoich. amts. at -78°C for 9 h, warming to room temp., stirring for 15 h; solvent removal (vac.), stirring with pentane for 1 h, filtration, concn. of filtrate, crystn. (-78°C, 6 h); further crop on concn. of filtrate; elem. anal.;

1: toluene 2: H2SO4 / water; tetrahydrofuran; diethyl ether View Scheme