Design,Synthesis And Application Of Heterocyclic Organoantimony And Organobismuth Complexes With High Stability

Antimony and bismuth elements are easy to form metal complexes with various structures and specific physical and chemical properties with metal atoms or nonmetal atoms due to their unique outer electronic configuration of ns²np³,which has attracted extensive attention of researchers at home and abroad.In recent years,with the development of organometallic chemistry,some organometallic complexes containing antimony and bismuth have been synthesized one after another,and have shown good application potential in the fields of medicine,materials,organic synthesis,catalysis,etc.However,the organoantimony（organobismuth）complexes disclosed at present have few types,single structure and composition,poor stability and easy denaturation in water or air,which limits the further application research of organoantimony（organobismuth）complexes in various fields.Based on the advantages of heterocyclic structure,a series of heterocyclic organoantimony（organobismuth）complexes with high stability have been designed and synthesized.The composition,structure and physical and chemical properties of the complexes were analyzed by nuclear magnetic resonance,single crystal X-ray diffraction,high resolution mass spectrometry,Fourier infrared spectrum and thermal gravimetric analyzer.Their potential applications in Lewis acid catalysis,anti-tumor and other fields were explored,and the mechanism of action of the complexes was deeply discussed.The main innovative research results and conclusions are as follows:1.An eight-membered heterocyclic organoantimony（III）complex Cy N（C₆H₄CH₂）₂Sb NO₃（Sb2）containing intramolecular N→Sb coordination was designed and synthesized by ion exchange method.Its composition and structure were analyzed and characterized by nuclear magnetic resonance,single crystal X-ray diffraction,Fourier infrared spectrum and o ther technical means.Thermal analysis and Hammett indicator method were used to prove that it has good air stability and strong Lewis acid strength.The catalytic performance of complex Sb2 in the synthesis of benzimidazole derivatives from aromatic aldeh yde and o-phenylenediamine was investigated.The results show that when the amount of catalyst Sb2 is 10 mol%,the catalytic efficiency is the best,and the yield of the target compound1-benzyl-2-phenylbenzimidazole（3a）can reach 90%.In addition,the ca talytic system also has a wide substrate application range and good functional group compatibility,and can still maintain high catalytic efficiency and excellent recycling performance in a 5-fold amplification experiment.2.Two kinds of heterocyclic organobismuth（III）complexes（C₆H₄CH₂OCH₃）₂Bi Cl（Bi1）、（C₆H₄CH₂O^tBu）₂Bi Cl（Bi2）with intramolecular O→Bi coordination were prepared.The structure was characterized by nuclear magnetic resonance,single crystal X-ray diffraction and high resolution mass spectrometry.CCK-8 method was used to evaluate the growth inhibitory effects of the above two complexes on liver SMMC-7721 cancer cells and lung A549 lung cancer cells.Cisplatin,a commonly used clinical anticancer drug,and the corresponding ligand precursors L1 and L2 were selected as controls.The research results show that Bi1 is the most biologically active complex,especially for liver SMMC-7721 cancer cells,the concentration of the semi-lethal rate is as low as 1.05±0.14μM（cisplatin is 25μM）,which is obviously superior to the traditional metal anti-tumor drug cisplatin and has a good medicinal prospect.