A disparate 3-D silver(I) coordination polymer of pyridine-3,5-dicarboxylate and pyrimidine with strong intermetallic interactions: X-ray crystallography, photoluminescence and antimicrobial activity

A polymeric silver(I) complex, [Ag4(μ-pydc)2(μ-pm)2]n (1) (pydc = pyridine-3,5-dicarboxylate and pm = pyrimidine), has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. X-ray crystallographic data of 1 revealed that pydc exhibits two different coordinaton modes that play a key role in the construction of the 3-D crystal network including Ag–carboxylate clusters in which close Ag–Ag distances exist. The magnitudes of close Ag–Ag interactions in second-order energy (E2) have been revealed by natural bond orbital analysis performed with single point energy calculation using the experimental geometry of 1. Furthermore, the luminescent properties of 1 show strong fluorescence with two emission maxima in the visible region. Also, 1 has antifungal activity on Candida albicans (MIC value, 4 μg mL−1) and good antibacterial activity on micro-organisms (MIC value, 64–256 μg mL−1). Graphical Abstract A polymeric silver(I) complex [Ag4(μ-pydc)2(μ-pm)2]n (1) consisting four coordinatively different silver(I) centers with excellent complementary assembly of pyridine-3,5-dicarboxylate(pydc) and pyrimidine(pm) ligands. 3D crystal structure of 1 has been determined by X-ray single crystal analysis and it has been identified that existence of intriguing close intermetallic interactions in addition to the presence of differently coordinating two pydc ligands. Strong solid-state fluorescence property and, effective antimicrobial behaviour of 1 has been also demonstrated.