Nonconventional Hydrogen Bonds between Silver Anion and Nucleobases: Size-Selected Anion Photoelectron Spectroscopy and Density Functional Calculations
Nonconventional Hydrogen Bonds between Silver Anion and Nucleobases: Size-Selected Anion Photoelectron Spectroscopy and Density Functional Calculations
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银阴离子和核碱基之间的非常规氢键：尺寸选择的阴离子光电子能谱和密度泛函计算
DOI：
10.1021/acs.jpca.7b09428
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发表时间：
2017
影响因子：
2.9
通讯作者：
Zheng Wei Jun
中科院分区：
文献类型：
--
作者：
Wang Peng;Xu Hong Guang;Cao Guo Jin;Zhang Wen Jing;Xu Xi Ling;Zheng Wei Jun
我们用气相阴离子光电子能谱和密度泛函理论相结合的方法对核碱银配合物进行了研究。通过比较理论计算和实验测量，确定了碱基-银-络合物的最可能结构。根据光电子能谱估算出尿嘧啶-银、胸腺嘧啶-银、胞嘧啶-银和鸟嘌呤-银的垂直分离能分别为2.18±0.08、2.11±0.08、2.04±0.08和2.20±0.08 eV。腺嘌呤-银-在实验中有两个异构体共存，两个异构体的实验VDEs分别为2.18 eV和2.53 eV。在最可能的碱基异构体中，尿嘧啶、胸腺嘧啶和胞嘧啶通过N-H···Ag和C-H···Ag氢键与Ag-离子相互作用，而腺嘌呤和鸟嘌呤通过两个N-H···Ag氢键与Ag-阴离子相互作用。N-H···Ag氢键可表征为中等或强氢键。结果表明，银离子与碱基的结合位置受去质子化能和相邻两个X-H基团的空间效应的影响。
We conducted combined gas-phase anion photoelectron spectroscopy and density functional theory studies on nucleobase-silver complexes. The most probable structures of the nucleobase-Ag–complexes were determined by comparing the theoretical calculations with the experimental measurements. The vertical detachment energies (VDEs) of uracil-Ag–, thymine-Ag–, cytosine-Ag–, and guanine-Ag–were estimated to be 2.18 ± 0.08, 2.11 ± 0.08, 2.04 ± 0.08, and 2.20 ± 0.08 eV, respectively, based on their photoelectron spectra. Adenine-Ag–has two isomers coexisting in the experiment; the experimental VDEs of the two isomers are 2.18 and 2.53 eV, respectively. In the most probable isomers of nucleobases-Ag–, uracil, thymine, and cytosine interact with Ag–anion via N–H···Ag and C–H···Ag hydrogen bonds, while adenine and guanine interact with Ag–anion through two N–H···Ag hydrogen bonds. The N–H···Ag hydrogen bonds can be characterized as medium or strong hydrogen bonds. It is found that binding sites of the Ag anion to the nucleobases are affected by the deprotonation energies and the steric effects of two adjacent X–H groups.