Two Ag(I) coordination polymers derived from melamine and dicarboxylates: Syntheses, crystal structures and thermal stabilities

Two mixed-ligand Ag(I) coordination polymers (CPs), [(NH4)Ag3(MA)2(suc)2]n (1), [Ag2(MA)2(adip)·CH3OH·H2O]n (2), (where MA = melamine, H2suc = succinic acid, H2adip = adipic acid) have been synthesized and structurally characterized by element analysis, IR and X-ray single-crystal diffraction. The CP 1 is a three-dimensional (3D) framework in which the MA acts as a tridentate ligand and suc2− anion shows three types of coordination modes. Each Ag(I) ion acts as a 4-connected node to generate three- and six-membered cycles, as a result, the network can be simplified to be an overall multi-layered Kagomé topology. The CP 2 is a 2D single-layer structure constructed by tridentate MA ligands and adip2− anions. The adjacent single-layers are inter-linked to form a double-layer 2D structure through the Ag⋯Ag interactions. Two CPs structurally vary from 2D sheet to 3D framework, which indicates that the different dicarboxylates and coordination modes of MA ligand have significant influence on the final structures. Moreover, the thermal stabilities of them were also discussed.