The gas-phase hydration of Mg2+ complexes with deprotonated uracil (U), thymine (T), uridine (Ur , uracil riboside), and thymidine (Tdr , thymine deoxyriboside) was studied. The aim of the work was to analyze the hydration of product ions (eg, [2U-H+Mg]+ ) formed as a result of the collision induced dissociation of the respective parent ion (eg, [3Ur -H+Mg]+ ). The efficiency of gas-phase hydration of the ions [2U-H+Mg]+ and [2T-H+Mg]+ was similar. However, the efficiency of gas-phase hydration of the ion [U+Ur -H+Mg]+ was much higher than that of gas-phase hydration of the ion [T+Tdr -H+Mg]+ . On the basis of the mass spectra obtained and the performed molecular modelling, it was concluded that in the ion [T+Tdr -H+Mg]+ , we deal with a steric hindrance due to the presence of a sugar moiety, which affects water attachment. In the ion [U+Ur -H+Mg]+ , the position of the sugar moiety does not affect water attachment.

中文翻译：

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Mg2 +配合物与去质子化的尿嘧啶，胸腺嘧啶，尿苷和胸苷的气相水合。

研究了Mg2 +与去质子化尿嘧啶（U），胸腺嘧啶（T），尿苷（Ur，尿嘧啶核糖苷）和胸苷（Tdr，胸腺嘧啶脱氧核糖苷）的气相水合。这项工作的目的是分析由于母离子碰撞引起的离解（例如[3Ur -H + Mg] +）而形成的产物离子（例如[2U-H + Mg] +）的水合）。离子[2U-H + Mg] +和[2T-H + Mg] +的气相水合效率相似。然而，离子[U + Ur -H + Mg] +的气相水合效率远高于离子[T + Tdr -H + Mg] +的气相水合效率。根据获得的质谱图和进行的分子建模，得出的结论是，在离子[T + Tdr -H + Mg] +中，我们处理了由于存在糖分而影响水的空间位阻附件。