in acetone under Ar atm. to soln. 1,3-bis(((dimethylsilyl)methyl)diphenylstannyl)propane in acetone at 0°C was added dropwise soln. HgCl2 in acetoneand stirred overnight at room temp.; soln. was filtered, solvent was removed in vacuo, residue was suspended in CH2Cl2 and filtered, filtrate was allowed to stand overnight at 5°C; elem. anal.;