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-(CH2NMe2)2C6H3] displays unusual dual behavior, being dimeric (LSbS)2, with the central Sb2S2 core, in the solid state but monomeric in solution. Sulfide 1 reacts with elemental S to give the unprecedented cyclic bis(pentasulfide) LSb(μ-S5)2SbL (2) with the central 12-membered ring Sb2S10.