in hexane under Ar; soln. of HGaCl2 in n-hexane treated with soln. of (Me3SiC2)4C6H2 in n-hexane at room temp.; heated under reflux for 14 h; filtered; ppt. washed with n-hexane; treated with Et2O; filtered; filtrate concd.; cooled to -45°C; elem. anal.;

potassium carbonate in tetrahydrofuran; methanol