几种苯并咪唑衍生物缓蚀性能的DFT研究

DFT Study of the Inhibitive Properties of Some Benzimidazole Derivatives

采用量子化学密度泛函理论(DFT)/B3LYP方法在6-311+G(d,p)水平上对2-苯基-苯并咪唑(A)、2-(4-甲基苯基)-苯并咪唑(B)、2-(4-氨基苯基)-苯并咪唑(C)、2-(4-一甲氨基苯基)-苯并咪唑(D)、2-(4-二甲氨基苯基)-苯并咪唑(E)5种苯并咪唑衍生物缓蚀性能与结构之间可能存在的关系进行了研究,用Fukui指数分析了分子中反应活性位点.全局活性参数最高占据轨道能量(EHOMO)、能隙(△E)、电负性(x)及电子转移数(ΔN)表明5种物质的缓蚀性能顺序为E>D>C>B>A.通过缓蚀剂分子质子化能(PA)分析,可以认为苯并咪唑类缓蚀剂在酸性环境中是以其吡啶N发生质子化形式存在,且通过咪唑环上大π键与金属之间发生作用.

In this paper,a theoretical study of five new benzimidazole derivatives,2-phenyl benzimidazole （A）,2-（4-methyl phenyl）benzimidazole （B）,2-（4-amino phenyl）benzimidazole （C）,2-（4-methylamino phenyl）benzimidazole （D）and 2-（4-two methylamino phenyl）benzimidazole （E）,was performed using density functional theory （DFT）at the B3LYP/6-31 1G ＋ （d,p）level in order to evaluate the possible relationship between corrosion inhibition efficiencies and electronic properties of molecules.In addition, the local reactivity was analyzed through the Fukui function.The global chemical reactivity parameters, such as EHOMO ,energy gap （△E）,electronegativity（x）and the fraction of electrons transferred from the＆amp;nbsp;inhibitor molecule to the metallic atom （△N）showed that the efficiency order of the five inhibitors was E〉D〉C〉B〉A.By analyzing the proton affinities it may be considered that these compounds existed as their stable protonated forms when the nitrogen atoms of pyridine were protonated.The results show that transferring electrons through delocalized bond is the primary way between benzimidazole derivatives and metal.