Synthesis, Characterization And Properties Of Chiral Coordination Polymers Containing L-Tartaric Acid Derivatives

Chiral coordination polymers are of intense interest in the fields of coordination chemistry, supramolecular chemistry and crystal engineering due to their intrinsic aesthetic topologies and their potentials in enantioselective separation, asymmetric catalysis, ferroelectric materials, nonlinear optical activities, magnetic materials, and so on. Most of chiral coordination polymers are prepared by assembling chiral ligands and metal ions, so the design and synthesis of chiral ligands is key to development of homochiral coordination polymers. It is of great importance for the development of supramolecualr chemistry and material science if chemists can prepare supramolecular complexes possessing expected structures and functions and establish the relationship of their structures and properties. In this thesis, we have prepared a series of chiral ligands from readily availab L-tartaric acid. Assembly of 2,2'-bipyridine or 4,4'-bipyridine and 2,3-O-isopropylidene-L-tartrate sodium with transition metals (Cu, Zn, Mn and Cd) by solvothermal technique has resulted in six novel chiral coordination polymers with unique properties. Their chemical formulas are listed as follows:[Cu(C₄H₆O₆)(2,2'-bipy)]·5H₂O (1)[Zn(C₄H₆O₆)(2,2'-bipy)]·5H₂O (2)[Cd(C₄H₆O₆)(2,2'-bipy)] (3)[Mn₂(C₇H₈O₆)₂(4,4'-bipy)₂(H₂O)₂]·6H₂O (4)[Zn₂(C₇H₈O₆)₂(4,4'-bipy)₂(H₂O)₂]·4H₂O (5)[Cu₂(C₇H₈O₆)₂(4,4'-bipy)₂(H₂O)₂]·4H₂O (6)All of the compounds have been characterized by elemental analyses, IR, and single crystal X-ray diffraction. The thermal stabilities, fluorescent properties and X-ray powder diffraction patterns of a part of the compounds have been studied. These compounds crystallize in chiral space groups. Among them, 3-6 crystallized in C2 polar point group and have possible ferroelectric behavior. Experimental results indicate that 3 indeed displays good ferroelectric behavior while 4 showes relatively lower ferroelectric responses with the character of antiferromagnetic.