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采用密度泛函理论B3LYP方法研究硫脲与Hg(Ⅱ)的配位特点.计算结果显示,硫脲S原子比N原子更容易与汞离子配位,前者作用能显著高于后者约129.0 k J/mol;S质子化后对Hg(Ⅱ)配位能力显著减弱.自然键轨道NBO分析显示,S的3s、3p价轨道与Hg(Ⅱ)4s空轨道存在较强成键作用;而N与Hg(Ⅱ)间成键作用则明显弱于前者.静电势分析发现,最负静电势出现在S原子周围,因此S原子是更佳金属配位位点;质子化的硫脲静电势为正,因此不易与Hg(Ⅱ)配位.
The coordination properties of thiourea and Hg (Ⅱ) were studied by using density functional theory (B3LYP) method. The calculated results show that S atom of thiourea is easier to coordinate with mercury ion than N atom, the former can be significantly higher than the latter by about 129.0 k J / mol; S protonation of Hg (Ⅱ) significantly reduced the ability of coordination.Natural bond orbital NBO analysis showed that S 3s, 3p valence orbitals and Hg (Ⅱ) 4s empty orbitals strong bond formation; and N And Hg (Ⅱ) are weaker than the former.The electrostatic potential analysis shows that the most negative electrostatic potential appears around the S atom, so the S atom is a better metal coordination site; the electrostatic potential of the protonated thiourea is Therefore, it is difficult to coordinate with Hg (Ⅱ).