Studies About Complexes Based On Pyridine-2,4,6-tricarboxylic Acid

Complexes constructed by pyridinecarboxlic acids have received enormous attention due to their uniqe supramolecular device, magnetism and luminescence applications, which have been the very significative research orientation in the material science and supramolecular chemistry. This thesis reviewed the representative pyridine-2,4,6-tricarboxylate complexes which have been reported so far according to their structure types from zero-dimensional to three-dimensianal, and discussed the studies about their relevant characters. The applications of pyridinecarboxylate complexes in magnetism, luminescence and biological activities and the synthesis strategies of them have also been reviewed. Then 14 complexes based on pyridine-2,4,6-tricarboxylate and transition metals or lanthanides, [Mn3(ptc)2(H2O)9]n (1), [Co3(ptc)2(H2O)2]n (2), [(Zn3O)Na0.5(H2O)(ptc)1.5] (3), [Co(bpy)(H2O)4]n{[Co(ptc)(H2O)]2}n (4), (Hbpy)2[Fe(Hptc)(ptc)]·3H2O (5), [Cu2(bpy)(ptc)]n·nH2O (6),{[La(ptc)(H2O)2]·1.5H2O}n (7), {[Ln2(H2O)5(ptc)2]·H2O}n (Ln=Sm (8), Tb (9), Dy (10)), [Dy(H2O)3(ptc)]·H2O (11), {[NdK(H2O)(ox)0.5(ptc)]·3H20}n (12),{[Ln2(H2O)4(ox)1.5(ptc)]·3.5H2O}n(Ln=Nd (13), Gd (14)) (H3ptc=pyridine-2,4,6-tricarboxylic acid; bpy=4,4'-bipyridine; ox=oxalic acid), which synthesized under different hydrothermal reaction parameters, such as molar ratio, temperature, duration and pH value of the solutions, were presented and their X-ray single crystal diffraction, X-ray powder diffraction, IR spectra, TG-DTA analyses, magnetic analyses and ferroelectric behavior were also demonstrated.1-3 were assembled by H3ptc and transition metal and exhibited various structure styles under different reaction temperature and pH values.1 contains noncentrosymmetric 1D chains which connected by extensive H-bonding interactions into 3D supramolecular frameworks. Magnetic analyses indicated antiferromagnetic coupling interactions between the Mn(II) ions within 1D chains. The electric hysteresis loop of 1 shows a typical ferroelectric feature. Complex 2 and 3 are both 3D metal-organic strutures. In 2, ptc ligands and metal ions act as 5-,6-connected nodes, respectively, to form a complicated topology net. The magnetic analyses indicated that the Co(Ⅱ) ions within the 2D layers show antiferromagnetic coupling interactions. Complex 3 displays the olivary cage unit which linked each other end to end to generate 1D chains. The resulting chains are futher bridged into 3D frameworks. The hydrothermal reactions of H3ptc, bpy and trasition metal result in the formation of complexes 4-6. The Fe(II) ions in reacton materials of 4 were oxidized into Fe(III) ions which chelated by Hptc2- and ptc3- to form [Fe(Hptc)(ptc)]n2n- coordination anion, while the lattice Hbpy+ ions are coordination cation. Interactionic H-bonding interactions between anions and cations contribute to the stabolization and the formation of the 3D supramolecular net. For 5, connection between ptc3- and Co(Ⅱ) within [Co(ptc)(H2O)]2n2n- result in the formation of 1D twin-chain which is found to be engaged in intrachainπ-πstacking interactions. The bpy ligands in [Co(bpy)(H2O)4]n2n+cations are bridged Co(Ⅱ) into 1D chains. The two kinds of 1D chains are interlinked each other through H-bonding interactions into sandwich-liked 3D stucture. Magnetic analyses indicated antiferromagnatic coupling interactions between Co(Ⅱ) ions within 1D anion chains. Complex 6 contains two kinds of copper ions Cu(I) and Cu(II), which locate in rarely dicoordinated linear and distorted pentacoordinated square pyramidal environments, respectively. The are bridged by ptc3- and bpy to generated (8·122)(8) topological 2D compound.The self-assembly of H3ptc and lanthanides afforded a series of multi-dimensional complexes 7-11. The complex 7 exhibits (4,6)-net 3D metal-organic frameworks (MOFs), which constructed by La(Ⅲ) ions and ptc3- ligands with the channel possessing approximate dimensionalities of 8.3 A×6.1 A. Complex 8-10 are isosturctures characteristic of novel herringbone-liked (4·63·82)(63) topological MOFs which constructed by ID twin-chains. Complex 11 contains the double layers with the topology of (4-82) which is very closely related to rutile subnet. At the excitation wavelength of 300 nm, two characteristic peaks at 482nm(4F9/2-6H15/2) and 573 nm(4F9/2-6H13/2) of Dy(Ⅲ) ion in 11 was observed.Complexes of 12-14 were obtained from hydrothermal reactions of H3ptc, oxalic acid and lanthanides uner different reaction parameters. The (42·6·84·102·12)(42·6)(8) topology of complex 12 is builded by 3-connected nodes Nd(Ⅲ) and 5-connected nodes ptc3-, in which the layer is very similar to the layer of graphite crystal lattice.13 and 14 are isosturctures obtained under same reaction method. The Ln2 dimer units and ptc3- ligands in them are defined as 6-connected and 3-connected node, respectively, to generate a 3D (42·6-810·10·12)2(42·6)2(8)3 topology which is recognized as r-Nb2O5 net.