Nonconventional behavior of NCN-chelated organoantimony(III) sulfide and isolation of cyclic organoantimony(III) bis(pentasulfide).

Organoantimony(III) sulfide (1) containing the NCN chelating ligand L [L = 2,6-(CH(2)NMe(2))(2)C(6)H(3)] displays unusual dual behavior, being dimeric (LSbS)(2), with the central Sb(2)S(2) core, in the solid state but monomeric in solution. Sulfide 1 reacts with elemental S to give the unprecedented cyclic bis(pentasulfide) LSb(mu-S(5))(2)SbL (2) with the central 12-membered ring Sb(2)S(10).