Study of the Isomeric Positional Effect of N-Mptc Ligands on the Structural Diversity of Zn(Ii) Semi-Rigid Coordination Polymers, Containing H-Bond Induced 2d Supramolecular Aggregates: Synthesis, Crystal Structure, Thermal Analysis, and Luminescence Properties

Two new Zn(II)-Coordination Polymers (CPs) based on the use of a new type of n-methyl pyridyl triazole carboxylate semi-rigid organic ligands (n-MPTC), L1 and L2 (where n = 3 and 4, respectively) have been prepared to systematically investigate the influence of the isomeric positional effect on their structures.The organic ligands were obtained by saponification from its respective ester precursor ethyl-5-methyl-1-(pyridin-3-ylmethyl)-1H-1,2,3-triazole -4-carboxylate (P1) and ethyl-5-methyl-1-(pyridin-4-ylmethyl)-1H-1,2,3-triazole-4-carboxylate (P2), resulting in its respective sodium salt, 3-MPTC, and 4-MPTC. The structure's CPs were determined by single-crystal X-ray diffraction. Structural analysis reveals that both CPs have 2D supramolecular structures induced by hydrogen bonds. In compound [Zn(L1)]n (1), the 2D supramolecular aggregate is built by hydrogen bond interactions between oxygen and hydrogen atoms from organic molecules neighbor, whereas in the compound [Zn(L2)×4H2O]n (2) the water molecules link 1D polymeric chain forming a 2D supramolecular aggregate. This work indicates that the isomeric effect in the semi-rigid ligands plays a vital role in constructing the Zn(II) coordination polymers, helped by the presence of methylene spacer group, in the final structural conformation. The thermal, luminescent, also studied and reported in detail.