Syntheses, structures and properties of three novel coordination polymers with a flexible asymmetrical bridging ligand

Three novel coordination polymers with different structural motifs, [Ag(pmtmb)]n (1), [Cd(pmtmb)2(H2O)]n (2) and [Cu(pmtmb)2]n (3), have been synthesized with a flexible asymmetrical bridging ligand, 4-(2-pyrimidylthiomethyl)benzoic acid (Hpmtmb). X-ray diffraction analyses show that 1 is a 2D layer containing unusual zigzag Ag chains based on mixed ligand-supported and ligand-unsupported Ag–Ag interactions, 2 is a necklace structure that further linked through hydrogen bonding to form a 2D sheet, and 3 is a 3D compact framework full assembled from 1D centipede-like chains via π–π stacking interactions. Interestingly, the ligand pmtmb adopts different configurations and coordination modes in the solid structures of these complexes. Furthermore, three complexes exhibit remarkable thermal stability and the complexes 1 and 2 exhibit intense green and purple luminescence, respectively.