A new route to polyselenoether macrocycles. Catalytic macrocyclization of 3,3-dimethylselenetane by Re-2(CO)(9)SeCH2CMe2CH2

3,3-Dimethylselenetane (SeCH2CMe2CH2, DMSe) was cyclooligomerized catalytically at 115 degrees C by the complex Re-2(CO)(9)(SeCH2CMe2CH2) (1). Three new polyselenoether macrocycles, 3,3,7,7-tetramethyl-1,5-diselenaeyclooctane (2; Me(4)8Se2), 3,3,7,7,11,11-hexamethyl-1,5,9-triselenacyclododecane (3; Me(6)12Se(3)), and 3,3,7,7,11,11,15, 15-octamethyl-1,5,9,13-tetraselenacyclohexadecane (4; Me(8)16Se4), along with a polymer were obtained. Two complexes of 3, Re-2(CO)(9)(Me(6)12Se3) (5) and Cu4I4(mu-Me(2)12Se3)(2) (6),were obtained from the reactions with Re-2(CO)(9)(NCMe) and CuI, respectively. All three macrocycles and the complexes 1, 5, and 6 were characterized crystallographically. In all cases the gem-dimethyl groups of the macrocycles are directed toward the exterior of the rings. Interestingly, some methylene groups are directed toward the interior of the ring. Compound 5 contains an eta(1)-Me(6)12Se3 ligand, while compound 6 contains bridging eta(2)-Me(6)12Se3 ligands that link Cu4I4, clusters into a three-dimensional network in the solid state.