| Recently, metal carboxylates have exhibited intriguing applications in a number of fields such as non-linear optical materials, magnetism, conductivity, sorption, luminescence and catalysis due to their unique properties, various coordination modes. Until now, thousands of metal carboxylates have been synthesized and characterized. In particular, supramolecular compounds have been a focus of inorganic synthesis and progressed at a rapid rate.Three new coordination compounds have been designed and synthesized by CoII, NiII, ZnII ions and 1, 4-Cyclohexanedicarboxylic acid , 2,2'-bipyridine ligands on the basis of hydrothermal technique and/or water solution synthesis methods. They have been characterized by elemental analyses, IR, XRPD, TG and single crystal X-ray diffractions. The thermal stabilities, fluorescent activity and isomer separation of 1,4-cyclohexanedicarboxylic acid of these compounds have been studied.1. Two supramolecular compounds, [M(2,2'-bipy)(H2O)4][1,4-chdc] (M=Co, Ni; 2,2'-bipy = 2,2'-bipyridine, 1,4-chdcH2=1,4-cyclohexanedicarboxylic acid ), were synthesized. Single crystal X-ray diffraction analysis revealed that [Co(2,2'-bipy)(H2O)4]2+ units and adjacent 1,4-chdc2– form a single layer by hydrogen bonding and electrostatic interactions along the ac-plane, and then two symmetry-related single layers interact with each other by hydrogen bonding, resulting in a double layer, which further forms a 3D structure byπ-πstacking. [Co(2,2'-bipy)(H2O)4][trans-1,4-chdc] (1) [Ni(2,2'-bipy)(H2O)4] [cis -1,4-chdc] (2)The most attractive structural feature of the two compounds is that 1,4-chdc2– possesses only trans- or cis- conformation although there are both cis and trans conformations in the raw material. It means that the control of the cis/trans conformation of 1,4-cyclohexanedicar- boxylic acid by changing the reaction conditions is possible.2. A 3D polymer has been synthesized by a d10 transition metal Zn and 1,4-chdcH2 in hydrothermal condition. Zn5(μ3-OH)2(trans-chdc)4 (3)Compound 3 is constructed from a infinite rod-shaped Zn-O-C secondary building unit interconnected by -C6H12- cyclohexane rings of the ligands. The topology of the framework can be regarded as hex type. The fluorescent activity is studied at room temperature. |
