in toluene a soln. of trimethylphosphane is dropped to a suspension of (C8H14B)2Se2 in toluene, stirring at room temp. for 2 h, removing of the solvent, sublimation of SePMe3 at 60-80°C/0.001 Torr and of (C8H14B)2Se(PMe3) at 110-120°C/0.001 Torr;