Study On The Synthesis And Luminescent Properties Of The Benzimidazoles Zinc Complexes

Owing to the excellent optical performance and biological activity of the benzimidazoles derivatives zinc coordination compounds,they can be widely used as optoelectronic materials,biological simulation materials and catalytic materials in chemical industry.In this paper,from the perspective of the luminescent property of the benzimidazoles zinc complexes,a seies of benzimidazoles derivatives and its zinc complexes were synthesized and all of them were characterized.The results were as follows:?1?Benzimidazole?BIM?and four other benzimidazoles derivatives:2-methylbenzimidazole?MBIM?,2-phenylbenzimidazole?PBIM?,2-?2-hydroxyphenyl?benzimidazole?HPBIM?and 2-styrylbenzimidazole?SEPBIM?were prepared successfully.The synthesized compounds were characterized by elemental analysis,FTIR,UV-vis and ¹HNMR.The optimal conditions of synthesizing of2-styrylbenzimidazole were obtained first time.The optimal reaction conditions were as follows:the liquid-solid ratio?mL/g?of catalyst was 0.75,the mole ratio of raw materials was 1:1,the reaction temperature was 180?and the reaction time was 4h.The highest yield of SEBIM reached to 67.8%.Moreover,under the optimum synthetic conditions,the yield of BIM,MBIM,PBIM,and HPBIM reached to 90.3%,85.1%,60.4%,51.1%,respectively.?2?Nine zinc coordination compounds were prepared by cooperating five benzimidazoles derivatives with two different kinds of zinc compounds?zinc acetate and zinc chloride?,respectively.The complexes are ZnBIM₂?OAc?₂,ZnMBIM₂?OAc?₂,ZnPBIM₂?OAc?₂,ZnHPBIM₂,ZnSEBIM₂?OAc?₂,ZnBIM₂Cl₂,ZnMBIM₂Cl₂,ZnPBIM₂Cl₂,ZnSEBIM₂Cl₂.All above products were characterized by elemental analysis,FTIR,UV-vis,conductivity and DSC.?3?The photoliuminescent properties of the ligands and the zinc complexes were investigated.The fluorescence of the ligands should be attributed to?-?^*transition.And the emission of the zinc complexes due to ligand-to-metal charge transfer.It can be obviously found that the intensity of emission became stronger as increasing the conjugation degree of ligands.Additionally,the luminescent properties of zinc complexes were also affected by the zinc ions from different compounds.