in toluene under inert atmosphere; toluene added to mixt. of NH4(P(O-n-Pr)2Se2) andFe complex; refluxed in oil bath for 4 h with stirring; filtered hot; filtrate evapd. to dryness; purified by column chromy. (silica gel, hexane-ethyl acetate 10:1); second band collected; solvent evapd.; elem. anal.;