Synthesis and structural characterization of metal complexes of some double-betaine and N,N'-dioxide ligands

Coordination polymers often possess the most desirable properties of both their organic and inorganic components, and thus metal complexes with organic bridging ligands have long been investigated as organic-inorganic hybrid materials with potential applications. A systematic investigation on the generation of coordination polymeric structures based on dicarboxylate-like ligands and N,N′-dioxide ligands are reported and discussed in the thesis.; Our research program on the generation of coordination polymeric structures based on dicarboxylate-like ligands involves the use of three isomeric double betaines, 1,4-bis(2-picolyloxyl)benzene-N,N ′-diacetate (L1), 1,4-bis(3-picolyloxyl) benzene- N,N′-diacetate (L2) and 1,4-bis(4-picolyloxyl)benzene-N,N ′-diacetate (L3) to bridge various metal atoms, primarily divalent transition metal ions, Ag(I) and La(III), together with the use of different counter anions. Seven double betaine derivatives and fourteen metal double betaine complexes have been synthesized and structurally characterized by single-crystal X-ray analysis. The results demonstrate that the double betaine ligands are versatile bridging ligands, which can easily generate one- and two-dimensional networks with metal ions. With the contribution of hydrogen bonding and π-π interactions, more complicated and interesting three-dimensional frameworks can be obtained.; Direct reaction of 1,4-bis(2-picolyloxyl)benzene-N, N′-diacetate (L1) with divalent transition metal chlorides in aqueous solution leads to the formation of two isomorphous hydrogen-bonded three-dimensional networks {lcub}[M(H₂O) ₆] Cl₂·L1·2H₂O (M = Mn 8, Co 9){rcub} and three different types of one-dimensional polymeric structures {lcub}[Cu(μ-L1)Cl₂]_∞ 10, {lcub}[Zn(μ-L1)Cl₂]·2H ₂O{rcub}_∞ 11 and {lcub}[Cd₂(μ-Cl) ₂(μ-L1)Cl₂(H₂O)₂]·2H ₂O{rcub}_∞{rcub} 12.; The three isomeric double betaine ligands react with AgNO₃ in aqueous solution to afford one-dimensional double chains {lcub}[Ag₂L 1](NO₃)₂·3.5H₂O{rcub}_∞ 13, three-dimensional {lcub}[Ag₂L2](NO ₃)₂·6H₂O{rcub}_∞ 14, and three-dimensional trinuclear {lcub}[Ag₃L3](NO ₃)₃·3H₂O{rcub}_∞ 15, which are inter-connected by hydrogen bonding with additional stabilization through π-π stacking and Ag···Ag interactions.; Six La(III) coordination polymers have been obtained by the reaction between two isomeric double betaine ligands L1 and L 2 with three La(III) salts. The complexes obtained from the reaction of La(III) salts and L1 ligand are all mononuclear, while those from L2 are all binuclear polymers. (Abstract shortened by UMI.)...