Synthesis And Properties Of Metal Complexes Based On Nitrogen-containing Heterocyclic Ligands

In recent years,coordination metal complexes with N-heterocyclic ligand have been the subject of intensive investigation not only due to theirintriguing structural diversity,but also because of their potential biological and magnetic properties.（1）The complex [Zn（2,3-PDC）（DMIM）·H₂O]_n（1）（2,3-P D C = 2,3-Pyridinedicarboxylic acid,DMIM=2-Methylimidazole）was prepared under the condition of 150°C reflux heating.The five coordination mode of central Zn（Ⅱ）atom make it to form a square pyramidal structure.The Zn（Ⅱ）ions in complex 1are bridged by the 2,3-pyridinedicarboxylic acid ligands to form a one-dimensional chain.There is an interaction between the ligands,so that 2-methylimidazole as a terminal group is suspended on the five membered chelate ring formed by the 2,3-pyridinedicarboxylic acid ligand and the metal center.（2）The complex [Co（2,3-PDC）（H₂O）₂]n（2）was prepared under hydrothermal conditionsand heated at 150°C for 4d.The coordination motif of the Co（Ⅱ）atom is a distorted octahedron.Two parallel ligands in complex2 are connected with a pair of adjacent Co（Ⅱ）atoms in the form of a head to tail connection to form an edge fused ring chain.For both complexes 1 and 2,their chains can be connected into a three-dimensional frame structure through hydrogen bonds.Bothcomplexes have been characterized by elemental analysis,IR spectra and thermogravimetric analysis（TGA）.The results are consistent with the results of crystal analysis.（3）The biological activity test of complex 1 and 2 showed that both of them had some inhibitory effects on some plants.（4）We have investigated the magnetic properties of the complex[Co（2,3-PDC）（H₂O）₂]_n（2）by means of broken symmetry（BS）with density functional theory（DFT）.The results show that there is a strong ferromagnetic interaction between dinuclear Co（Ⅱ）.