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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Competition between X…H…Y Intramolecular Hydrogen Bonds and X…Y (X = O, S, and Y = Se, Te) Chalcogen-Chalcogen Interactions
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Competition between X…H…Y Intramolecular Hydrogen Bonds and X…Y (X = O, S, and Y = Se, Te) Chalcogen-Chalcogen Interactions

机译：X…H…Y分子内氢键与X…Y（X = O，S和Y = Se，Te）之间的竞争硫族元素-硫族元素相互作用

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High-level G2(MP2) ab initio and B3LYP/6-311 + G(3df,2p) density functional calculations have been carried out for a series of β-chalcogenovinylaldehydes, HC(=X)-CH=CH-CYH (X = O, S; Y = Se, Te). Our results indicate that for X = O, S and Y = Se, the O-H…Se and the S-H…Se intramolecular hydrogen bonds compete in strength with the O…Se and the S…Se interaction, while the opposite is found for the corresponding tellurium-containing analogues. The different strength of O-H…Se and O…H-Se intramolecular hydrogen bonds explains why the chelated enolic and keto forms of selenovinylaldehyde are very close in energy, although enol-tautomers are estimated to be about 10 kcal mol~(-1) more stable than keto-tautomers. The situation is qualitatively similar for selenothiovinylaldehyde, although the S-H…Se and S…H-Se intramolecular hydrogen bonds (IHBs) are weaker and much closer in strength, and the energy gap between enethiol- and thione-tautomers also smaller. The relative strengths of the X-H…Te and X…H-Te (X = O, S) IHBs, are very similar to those of the corresponding selenium analogues. However, there are dramatic differences as far as the X…Y (X = O, S; Y = Se, Te) interactions are concerned, which for Se-derivatives are rather small, while for Te-compounds are very strong. An analysis of these chalcogen-chalcogen interactions indicates that both, the electrostatic and the dative contributions are smaller for Se- than for Te-derivatives. In the latter, the electrostatic component clearly dominates when X = O, while the opposite is found for sulfur-containing derivatives. We have also shown that these two components are entangled in some manner, in the sense that strong electrostatic interactions favor the n_O-σ~*_(YH) (or n_S-σ~*_(YH)) dative interaction. the proton-transfer processes in species with IHBs were also investigated.
机译：对一系列β-硫属元素炔醛进行了高级G2（MP2）从头算和B3LYP / 6-311 + G（3df，2p）密度泛函计算（HC（= X）-CH = CH-CYH（X ＝ O，S; Y ＝ Se，Te）。我们的结果表明，对于X = O，S和Y = Se，OH…Se和SH…Se分子内氢键的强度与O…Se和S…Se的相互作用竞争，而相应的相反。含碲类似物。 OH…Se和O…H-Se分子内氢键的不同强度解释了为什么烯醇互变异构体的螯合烯醇和酮形式的硒烯乙烯基醛的能量非常接近，尽管烯醇互变异构体估计约为10 kcal mol〜（-1）更多比酮基互变异构体稳定。尽管S-H…Se和S…H-Se分子内氢键（IHBs）较弱且强度更近，并且烯硫醇-硫代互变异构体之间的能隙也更小，但硒代硫乙烯基醛的情况在质量上相似。 X-H…Te和X…H-Te（X = O，S）IHB的相对强度与相应的硒类似物的相对强度非常相似。但是，就X…Y（X = O，S; Y = Se，Te）相互作用而言，存在巨大差异，对于Se衍生物而言，相互作用很小，而对于Te化合物而言，相互作用非常强。对这些硫族元素-硫族元素相互作用的分析表明，Se和Fe的静电作用和导数作用都小于Te衍生物。在后者中，当X = O时，静电成分明显占优势，而含硫衍生物则相反。我们还表明，在强烈的静电相互作用有利于n_O-σ〜* _（YH）（或n_S-σ〜* _（YH））阶跃相互作用的意义上，这两个组件以某种方式纠缠在一起。还研究了具有IHBs的物种中的质子转移过程。

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