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

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.

Density Functional Theory study for the Coordination Behavior between 3-Amino-5-mercapto-1,2,4-triazole and Ag(I)

The coordination between 3-amino-5-mercapto-1,2,4-triazole and Ag(I) was theoretical studied using density functional theory ( DFT ) B3LYP method. The results showed that significantly stronger coordination ability has been found with the ad-L ligand in comparison to the L ligand, and apparently higher stabilization energy of about 443.8 kJ/mol has been found for the SN coordination model, in addition, 336.8 kJ/mol occurred to the N2 coordinated complex. Later NBO analysis suggested strong orbital overlap occurred to the Ag(I) and the ligand. The electrostatic potential analysis indicated that the silver Ag(I) preferred more to the N1 and N2 atoms 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 N7 finally increased the positive electrostatic potential, then decreased coordination ability of this atom.