3-氨基-5-巯基-1,2,4-三唑与Ag(I)配位作用的密度泛函理论研究

Density functional theory study for the coordination behavior between 3-Amino-5-mercapto-1,2,4-triazole and Ag(I)

采用密度泛函理论B3LYP方法研究3-氨基-5-巯基-1,2,4-三唑与Ag(I)的配位特点.计算结果显示,ad-L配体配位能力显著高于中性配体L,其中SN配位模式稳定化能高于中性配体约443.8kJ/mol,且N2模式稳定化能高于中性配体约336.8 kJ/mol;而p-L配体相互作用能和稳定化能均为负值.自然键轨道(NBO)分析显示配体与Ag(I)间存在较强轨道作用.静电势分析发现,L配体最负静电势出现在N1、N2原子周围,因此N1、N2位点更易与Ag(I)配位; ad-L配体静电势为负,因此与Ag(I)作用增强,而质子化的配体p-L静电势为正,因此不易与Ag(I)配位.

The coordination between3-amino-5-mercapto-1,2,4-triazole and Ag(I)was theoretically studied using density functional theory(DFT)B3LYP method.The results showed significantly stronger coordination ability for the ad-L ligand in comparison to the neutral ligand L,apparently highest stabilization energy by about443.8kJ/mol has been found for the SN coordination model compared with the neutral ligand,in addition,moderately higher value by about336.8kJ/mol occurs to the N2coordinated complex.While negative interaction energy and stabilization energy have been found for the complex with protonation of amino group.Later the natural bond orbital(NBO)analysis suggested strong orbital overlap occurred to the Ag(I)and the ligand.The electrostatic potential analysis indicated that the silver Ag(I)prefers to the N1and N2atoms compared to the mercapto S because of apparently more negative electrostatic potential.Comparably stronger interaction has been discovered for the ad-L ligand because of more negative electrostatic potential resulting from acid dissociation of mercapto.While protonation of N7finally increases the positive electrostatic potential,then decreases coordination ability of this atom.