Homochiral Coordination Polymers With The Semi-rigid Chiral Carboxylic Acid Ligands

In the current, chiral coordination polymers have became one of the main research fields of chemistry because of their wide applications in adsorption, separation, asymmetric catalysis, light, electricity, magnetism, and so on. During the complex coordination ability and flexible manner, carboxylic ligands assembled with the metal ions can generate rigid structure comprising a larger aperture. In this paper, we synthesized two chiral ligands as the primary ligand. Under the guidance of coordination polymer crystal engineering, ten new coordination polymers have been prepared, including 2D and 3D structure. Single-crystal structure analysis, IR and PXRD of all the above complexes have been carried out. Some complexes also have been characterized by Fluorescent, Magnetic properties and Thermal stability.This work is mainly divided into the following sections:1. Synthesis and Characterization of transition metal coordination polymers with chiral dicarboxylatesHydro(solvo)thermal reactions of L-TMA and transition metal ions(Zn(Ⅱ)、 Cd(Ⅱ)、Cu(Ⅱ)、Co(Ⅱ)) or in the presence of a series of systematically varied bridging and terminal ligands (L’=4,4’-bipyridine, bpe, bpea, phen) afford five coordination compounds. Single-crystal X-ray diffraction reveal that compound w-1 and w-2 are doubly interspersed 2D structure, w-5 is a 2D structure, w-3 and w-4 are 3D structures. We have researched the fluorescence properties of complexes w-1 and w-2. Compared with the free ligand, the emission peak of complex w-1 shows significant redshift, while complex w-2 basically shows agreement with the free ligand. With a porosity of 36.35%, the stability of the skeleton and the exchange of guest molecules were carried out for complex w-3. Complex w-4 is a new 3D topology with the topological symbol {6·104·12}{63}2{64·102}. What’s interesting, the oxygen atom of amide group in complex w-4 is also involved in the coordination. Because of the existence of a 1D chain of dinuclear Co units in complex w-5, we characterize the magnetic of complex w-5.The results show a weak antiferromagnetic interactions exist in complex w-5.2. Synthesis and characterization of transition metal coordination polymers with chiral tricarboxylatesTwo coordination polymers have been prepared by hydrothermal reactions of L-TMTA and transition metal ions Ni(Ⅱ). Complex w-6 is a 3D structure and Complex w-7 is a 2D structure. In both complexes, three carboxyl groups of L-TMTA ligand are protoned completely. The ligand with two carboxyl groups involved in the coordination builds a 3D skeleton complex 6 having a 1D pore structure, while the ligand with one carboxyl group involved in the coordination of the ligand resulting in a 2D layered compound 7. Similar to complex w-4, the oxygen atom of amide group in complex w-7 is also involved in the coordination.3. Synthesis and characterization of Rare-earth metal coordination polymersUsing the hydrothermal reactions of L-TMA ligand and Rare-earth metal ions Eu(Ⅲ), Gd(Ⅲ), Tb(Ⅲ), we synthesized three isomorphous coordination polymers. Single-crystal X-ray diffraction reveal that three complexes are twofold interspersed 3D structure. Each metal ion surrounded by four L-TMA ligands and one L-TMA ligand connected to two metal ions to form a 3D skeleton. Sodium acetate was added to adjust the pH of the system during the synthesis of these three complexes. Due to restrictive of chelating ligand 1,10-phen, it only playes a role in coordinating and regulating the direction of the L-TMA ligand.