Crystal Structure And Optical Properties Of Pyridine-2,6-dimethylacyl Derivatives

Based on the Pyridine-2,6-dicarboxylic acid ligand, through qualitativetransformation on the symmetrical carboxylic acid groups of pyridine ring-nitrogenatom bilaterally, designed to synthesize a special structure on both sides of thenitrogen atom of the pyridine ring which has an asymmetric organic compounds, ascomplexing to with different transition metals, train a serious of transition metalcomplex compound which have different structure. Analysed their single crystalstructure, IR, UV, and TG-DSC, while quantum chemical calculation, to explore theircrystal structure and optical properties. The five crystals to study are as follows:1. Tppahz·5H₂O （1）;2.[Cu（ppahz）（H₂O）]·3H₂O （2）;3.[Ni₃（paota）₂（OH）₂（H₂O）₂]·2H₂O （3）;4.[Zn₂（hpdaota）₂（H₂O）₄]·（H₂O）₄（4）;5.[Cu（pdaota）₂（furan）₂]·H₂O （5）;When we do X-ray diffraction experiments and structure parsing to the fivecrystals, the results show that the crystals1and2are triclinic system, and their spacegroup are P-1; crystal3and4are monoclinic crystal system, and their space group isP21/n; crystal5is cubic crystal system, and its space group is R3c. crystal2and5are complex of single core, complexes3is a coordination polymer, complex4is adual-core metal complexes, crystal1and2form a layered structure by intermolecularhydrogen bonds, and crystal3has one-dimensional chain structure. Metal complexes3and5are all five-ligand complexes, and have water molecule involved in the ligand,metal complexes4and5are hexacoordination complexes, while in the complex5nowater molecules are involved in the ligand, but the two solvent molecules furaninvolved in the ligand with the metal. In the five crystal lattice there are face π-π interaction, crystals1,2,3, and4also exist hydrogen bonding, so that they have astable crystal structure. Where in the unit cell of the complex4, a hole is formed inthe hydrogen bonding interactions, in the unit cell of complexes5, the orderlyarrangement of the sulfonic acid group of the ligand is also formed a hole. Whichmaking complexes4and5has the ability to capture small molecule compounds, andthat may make them become the potential energy storage materials.The crystal peak position of specific functional groups of the crystals areobtained by the analysis of infrared spectral data, and after the ligand coordinatedwith the metal, the peak position of crystals of organic compounds and metalcomplexes changes, and it showed the successful synthesis and cultured of metalcomplexes. We also do the fluorescence spectra and UV spectroscopy to the ligandcomplexes and metal complexes, made a qualitative discussion and analysis of theirfluorescence properties, the results show that the complexes3,4and5, when theirligand coordinate with the metal, its excitation and emission spectra are red shift.With quantum chemistry calculations to five crystal compounds and metalcomplexes show that the metal complexes of the frontier molecular orbital energy gapand pure organic ligand frontier molecular orbital energy level are different, itrelated to the ligand of the metal. Combined with the UV spectrum of the crystallinecompound and the metal complexes of the ligand, the structures coincide with thetheoretical analysis of metal complexes.