Synthesis And Structural Characterization Of Cobaltphosphate/Zincphosphate Framework Materials In Protic Deep Eutecitc Mixture

Metal phosphate framework materials with distinct crystal structures and abundant elemental components have potential performance in the field of catalysis, adsorption and emerging photoelectromagnetic. At present, most of the metal phosphate materials were synthesized by hydrothermal or solvothermal route in the presence of organic amines. Solvents and organic amines are crucial factors to synthesis phosphate materials, so it is one of the most important approaches to design and choose new reaction mediums with novel phosphate compunds.Ionic deep eutectic mixture composed of hydrogen donors with quaternary ammonium are used as both solvent and template agent in ionothermal synthesis of phasphates. However, tetraalkyl ammonium salts used in present have not rich structure types and their large space volume weaken the template role of themself. Compared with traditional quaternary ammoniums, protonated organic amines with more aboundant species and structures can form much richer ionic liquid system and hydrogen donors, which provides a wide range of choices to synthesis inorganic microporous materials.Herein, in order to reveal the template role either competition or synergy to synthesis new crystal materials as the starting point, the synthesis of MePO(Me=Co, Zn) was explored systematically in eutectic mixtures composed of protonated organic amines and urea derivatives(urea, 1,3-dimethyl urea and imidazolone) as both the solvent and template. Meanwhile, the structure directing effect of adding a small amount of inorganic alkali metal ions(Li+) on the final phase was also studied. The crystal structures were analyzed by single crystal diffraction data, combining PXRD, FT-IR, SEM, TG, and CHN elemental analysis to characterize the typical samples systematically. The main contents and results are listed as follows:1、In the case of urea/protonated organic amines deep eutectic system, NH4CoPO4-HEX and NH4 Zn PO4-ABW were achieved, which have three-dimensional 6-membered rings and 8-membered rings channel structure respectively. The result shows that the inorganic amine derived from urea as the template was occluded in the framework, which has a stronger template role than protonated organic amine cations: methylamine 、 dimethylamine 、trimethylamine、ethylamine、diethylamine、triethylamine.2、In the system of P2O5-ZnO(or CoO)-Li2O-1,3-dimethyl urea/protonated organic amine, five different products have been respectively synthesized by optimizing the synthetic conditions. In the absent of LiOH,(Co PO4)(CH3NH3) and(Zn PO4)(CH3NH3) with THO topology structure were isomorphous, which were obtained by using methyl amine cation as the template. Meanwhile, raising reaction temperature(220℃), a new layered compound Co3(PO4)4(NH4)2 was obtained and inorganic amine derived from excessive thermal decomposition as the template was occluded in the interlayer. In the presence of a small amount of LiOH, LiCo2PO4(CH3NH3) and LiZn2PO4(CH3NH3) with the novel 3D structure of 8-membered ring channel were isomorphous. As a component of inorganic framework elements, Li+ participated coordination as Li O4. This is the first reported that double metal phosphate porous materials were synthesized using methylamine as the template and Li+ took part in the framework coordination. Crystallographic structure analysis and element analysis show that thermal decomposition products(methylamine or inorganic amine) derived from 1,3-dimethyl urea have a stronger template role than protonated organic amine cations in the final framework.3、From the deep eutectic mixture composed of imidazolone and protonated organic amines, CoPO-PEU5 and ZnPO-PEU4 with DFT topology structure were synthesized. Protonated ethylenediamine from imidazolone was occluded in the framework of phosphates and had a stronger template role than protonated organic amine cations in the final framework.