ON THE HALOAMINATION OF DISELENIDES - SYN THESIS AND STRUCTURE OF THE8-MEMBERED RING CATION [ME(2)SN(2)SEME](++)(2)

N-halogen compounds of benzamidine and S,S-dimethylsulfone diimides re act with diselenides by Se-Se-bond cleavage yielding different types o f selenium-nitrogen compounds. With N-bromo-benzamidine the diazene de rivatives RSeN(Ph)CN=NC(Ph)NSeR 2a, b (a: R = Me; b: R = Ph) are forme d. In the reaction of N,N'-Dichloro-S,S-dimethylsulfone diimide, Me(2) S(NCI)(2), with diselenides cyclic hetero-selenonium salts [(Me(2)SN(2 )SeR)Cl](2) (4a, b) are obtained. The structure of the eight membered ring compound 4a was determined by x-ray crystallography (space group <P(1)over bar>, Z = 1) and compared with that of the isotypic sulfoniu m salt [(Me(2)SN(2)SMe)Br](2) (3a).