Coordination Polymers and Networks Constructed from Bidentate Ligands Linked with Sulfonamide and Silver(I) Ions

Abstract

Ligands that consist of pyridine rings linked by sulfonamide are simple and unique building blocks which form infinite polymers and networks via metal-coordination and hydrogen bonds (H-bonds). Single crystal X-ray analysis revealed that the complexation of bidentate ligands 1 and 2 bearing secondary sulfonamide with silver(I) ion results in the formation of [AgL2(OTf)] (1a), [Ag2(μ-L)2(OTf)2] (2a), and [AgL(OTf)]n (2b) complexes. The complex 1a assembled into extended one-dimensional (1D) chains through H-bonds between the N−H moieties of sulfonamide and nitrogen atom of pyridyl groups. These individual chains associated into a three-dimensional (3D) network structure via C−H···O interactions between pyridyl protons and the oxygen atom of sulfonamides. The complex 2a assembled into two-dimensional (2D) sheets through H-bonds between the N−H moieties of sulfonamide and H2O molecules. In the complex 2b, enantiopure continuous 1D chain [AgL(OTf)]n was formed. In these structures, the silver(I) centers have a T-shaped stereochemistry in which each ion is coordinated by two pyridyl groups of the ligand and a trifluoromethane sulfonate anion. In the complex of ligands 3 and 4 with an ethyl group on the nitrogen atom of sulfonamide and silver(I) ions, continuous 1D homochiral chains [AgL(OTf)]n (3a) and helical polymers [AgL]n(OTf)n (4a) were formed. Both 1D homochiral polymers contained a racemic mixture of right- and left-handed coordination polymers, which assemble into 2D sheets and 3D networks via Ag···Ag, Ag···O, and C−H···O interactions.