Synthesis, Structure And Properties Of 1,2,3 - Triazole 4,5 - Dicarboxylic Acid And Transition Metal Complexes

Metal-Organic Frameworks not only have charming topological structures but also have widely promising applications in the fields of catalysis, luminescent, high-energy-density materials, molecular magnet and so on. It is indicated that organic ligands play a crucial role on the structure and function of coordination polymers. In this paper, eight compounds were prepared by reactions of 1,2,3-triazole-4,5-dicarboxylic acid (H3tda) with Cu(Ⅱ)/Zn(Ⅱ)/Cd(Ⅱ) transition metal ions in the presence of strong chelating coligands. The crystal structures and the physical and chemical properties of compounds 1-8 were discussed. The research contents in detail are summarized as follows:1. Under solution method and hydrothermal method conditions, seven novel compounds are synthesized by using 1,2,3-triazole-4,5-dicarboxylic acid as the first ligand and using the neutral containing nitrogen organic molecular such as 2,2’-bpy、phen as the second ligand with transition metal ions such as Cu(Ⅱ)/Zn(Ⅱ)/Cd(Ⅱ). The composition and structures of compounds 1-7 are determined by elemental analysis and single-crystal X-ray diffraction technique. Structural analyses reveal that H3tda adopts N,O-bidentate-chelating fashion connecting Cd(Ⅱ)/Zn(Ⅱ)/Cu(Ⅱ) ions generating four double nuclear structures [Cd2(Htda)2(phen)4](H2O) (1)、[Zn2(Htda)2(phen)4](H2O) (2)、Cu2(Htda)(bpy)Cl (4)、 [Cu2(tda)(phen)2(H2O)Cl](H2O)3 (5) and a one-dimensional chain-like structure [Cu(H2tda)(H2O)]n (7). Adopting N,O-and O,O-bidentate-chelating fashion combining Cd(Ⅱ) generating a 2D structure{[Cd3(tda)2(phen)3](CH3CH2OH)}n(3). Applying single and N,O-bidentate-fashion of H3tda coordinate to Cu(II) metal ion forming double nuclear structure [Cu2(Htda)2(H2O)6](H2O)2 (6).2. Thermoanalysis shows that the main frameworks of all compounds possess a higher stability under 300 ℃ by TG-DSC technique. At the same time, the abrupt collapse of the main frameworks indates the characteristic of energetic materials sharply releasing energy. Optical performance analysis presents that compound 1-3 present strong luminescent strength. Their emission spectra blue-shift compared with the free H3tda which may be assigned π*→π or π*→n charge transition of ligand.3. Under hydrothermal method conditions, a reticular 3D heterometallic metal-organic framework (MOF) [Cu4Na(Mtta)5(CH3CN)n (8) (N%=40.08%), has been synthesized, through in situ synthesis and structurally characterized by X-ray single crystal diffraction. There are two methods for the synthesis of compand 8, one is using 1,2,3-triazole-4,5-dicarboxylic acid as the main ligand, the other is using NaN3 instead of 1,2,3-triazole-4,5-dicarboxylic acid. The fluorescence spectra demonstrates that 8 undergoes an interesting structural transformation in aqueous solution, yielding the compound [Cu4Na(Mtta)5H2O]n (8a) as confirmed by 1H NMR, IR and PXRD. Thermoanalysis shows that compound 8 possesses excellent thermostability up to 335 ℃. The calculated detonation properties and the sensitivity test illustrates that compound 8 could be used as a potential explosive. The energetic compound 8 is explored as an additive to promote the thermal decomposition of the main component of propellants (AP、RDX and HMX) by DSC technique. It reveals that compound 8 could catalyze the decomposition of AP.