AMT在青铜器文物表面形成缓蚀膜的计算分析

利用密度泛函(DFT)、概念DFT、Electron Localization Function(ELF)和Fukui函数中的亲电反应函数及Multiwfn软件,在B3LYP/6-311+G(d,p)基组水平上研究了5-氨基-2-巯基-1,3,4-噻二唑AMT(a)]及其同分异构体AMT(b)]和四面体型配合物i Thiol-Cu-2AMT的几何构型和反应特性.通过计算研究发现,首先AMT(b)与青铜器表面的Cu2+形成平面型配合物i Thiol-Cu后再与AMT(b)相互作用,并最终形成不规则的四面体型i Thiol-Cu-2AMT.在i Thiol-Cu-2AMT中Cu19能与AMT(b)中的亲核性原子有效地结合,形成四面体结构后将Cu19离子保护起来,达到了保护青铜器不受腐蚀的目的;对i Thiol-Cu-2AMT结构中的活性位置分析及ELF拓扑研究后发现,在i Thiol-Cu-2AMT中N6、N15、S26和S35原子又可以与其它的Cu2+相互作用,逐步形成配位型聚合物保护膜i Thiol-Cu-2AMT]n.

Calculated analysis on inhibition interaction formed film of bronze cultural relics surface by AMT

The 2-aminino-5-mercapto-1,3,4-thiadizole (AMT (a)) and corresponding isomer AMT (b) Were studied by using the density functional theory (DFT), election localization function (ELF), electrophilic reaction functional of Fukui wavefunction analyzer and Multiwfn software methods. The geometries of coordinate protective films unit (iThiol-Cu-2AMT) was also completed optimized by B3LYP/6-311+G (d, p) and above methods. The calculated results indicated that the planar framework complex iThiol-Cu was formed firstly via AMT (b) and Cu2+ of the exterior bronze, and then irregular tetrahedral framework complex iThiol-Cu-2AMT was formed base on iThiol-Cu and Cu2+. It was been found that the Cu19 atom of iThiol-Cu-2AMT unit was enwrapped in tetrahedral framework, and reaction activity was reduced. In addition, the active reaction location of ithiol-Cu-2AMT were analyzed by Multiwfn analyzer and ELF topology methods, the results that the new coordinated bond N-Cu and covalent bond S-Cu were formed by N6, N15, S26 and S35 atoms with other Cu2+ cations respectively. The theoretical study results explained the high polymer film iThiol-Cu-2AMT]n can been formed in the case of situation.