in dimethyl sulfoxide byproducts: Hg; Irradiation (UV/VIS); nitrogen atmosphere; mercurial in deoxygenated solvent irradiated (at 350 nm in Rayonet Photoreactor, 40 °C, 3.5 h or 275-W sunlamp, 40 °C, 5 h);; mixt. poured into water; extn. with benzene; ext. washed (water) and dried (Na2SO4); concd.; PhCH2CH2Ph and PhCH2SePh analysed by (1)H NMR, GLC and GCMS;;