Study On Preparation And Properties Of Metal Complexs Based On Aza Organic Ligands

Coordination compounds have attracted extensive attention from researchers due to their diverse structures and excellent properties.They show potential application prospects in the fields of gas storage and separation,drug carriers,photoelectric catalysis,molecular recognition and other fields.In this paper,two supermolecular materials were prepared by solvothermal that2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthrene(BCP)and pyrazine as organic ligands,Cu(I),metal Co(II)as metal node.We have studied their performance in gas adsorption,iodine adsorption,dye molecule adsorption,and carbon dioxide reduction,based on the characterization of two supermolecular materials.The main content of the paper is summarized as follows:(1)Complex 1 was constructed from metal Cu(I)and BCP ligand by solvothermal method,which completely relied on?-?stacking to form an octahedral supramolecular cage.It belongs to the cubic system and crystallizes in the Fd-3 space group.The independent unit of complex 1contains one Cu(I)ion,two BCP ligands,as well as a formate ion and several guest molecules.Cu(I)is four-coordinated with four nitrogen atoms form two BCP ligands.Complex 1 was characterized by single crystal/powder X-ray diffraction,FT-IR spectroscopy,thermogravimetric analysis,and X-ray photoelectron spectroscopy.All the tests show that it has good thermal stability.Moreover,it has good stability in water and polar solvents.Gas adsorption test showed that complex 1 has good adsorption behavior for CO₂,and the adsorption capacity reached 79.02cm³/g at 195K.It also exhibits excellent iodine adsorption performance,with a loading of 1.5 g/g in KI₃ solution.In addition,complex 1 exhibits good semiconductor properties.The band gap structure of complex 1 was obtained by UV-Visible diffuse reflection and the Mot-Schottky curve from electrochemical workstation.On the basis of the UV-vis diffuse reflectance data,the optical bandgap of complex 1 was calculated to be 1.86e V.According to this,the conduction band of complex 1 could be estimated to be-1.09 V vs NHE.The valence band of Complex 1 was also estimated to be 0.77 V vs NHE.Complex 1 for photo-induced CO₂ reduction to make sense in theory,which gives good reasons to our further study.(2)The cobalt-based three-dimensional metal-organic framework material was assembled using Co(II)and pyrazine ligands.Further,two-dimensional ultra-thin MOF nanosheets were successfully obtained from the bulk MOF by liquid exfoliated method.Single-layer nanosheets were characterized by powder-X-ray diffraction,transmission electron microscopy,and atomic force microscopy.We have studied the photocatalytic performance of 2 D[Co(NCS)₂(pyz)₂]_nnanosheets for the photocatalytic reduction of CO₂ to CO,the CO production of 8662?mol/g and a CO selectivity of 80.69%,the H₂ production of 2073?mol/g in a mixed solvent CH₃CN/H₂O(v/v=4:1)under visible light irradiation for 8 hours.