School of Chemistry and BIO-21 Institute, University of Melbourne, Parkville, VIC 3010, Melbourne, Australia.
Acta Crystallogr C Struct Chem. 2023 Feb 1;79(Pt 2):43-51. doi: 10.1107/S2053229623000062. Epub 2023 Feb 17.
The crystal structure of the pyridine-substituted benzisoselenazolinone 2-(pyridin-3-yl)-2,3-dihydro-1,2-benzoselenazol-3-one (CHNOSe, 2), related to the antioxidant ebselen [systematic name: 2-phenyl-1,2-benzoselenazol-3(2H)-one, 1], is characterized by strong intermolecular N...Se(-N) chalcogen bonding, where the N...Se distance of 2.3831 (6) Å is well within the sum of the van der Waals radii for N and Se (3.34 Å). This strong interaction results in significant lengthening of the internal N-Se distance, consistent with significant population of the Se-N σ* antibonding orbital. Much weaker intermolecular O...Se chalcogen bonding occurs between the amide-like O atom in 2 and the less polarized C-Se bond in this structure. Charge density analysis of 2 using multipole refinement of high-resolution data allowed the electrostatic surface potential for 2 to be mapped, and clearly reveals the σ-hole at the extension of the Se-N bond as an area of positive electrostatic potential. Topological analysis of the electron-density distribution in 2 was carried out within the Quantum Theory of Atoms in Molecules (QTAIM) framework and revealed bond paths and (3,-1) bond critical points (BCPs) for the N...Se-N moiety consistent with a closed-shell interaction; however, the potential energy term is suggestive of electron sharing. Analysis of the electron localization function (ELF) for the strong N...Se and the weak O...Se chalcogen-bonding interactions in the structure of 2 suggest significant electron sharing in the former interaction, and a largely electrostatic interaction in the latter. Conversion of 2 to its N-methylated derivatives by reaction with methyl iodide [1-methyl-3-(3-oxo-2,3-dihydro-1,2-benzoselenazol-2-yl)pyridin-1-ium iodide, CHNOSe·I] and methyl tosylate [1-methyl-3-(3-oxo-2,3-dihydro-1,2-benzoselenazol-2-yl)pyridin-1-ium toluenesulfonate trihydrate, CHNOSe·CHOS·3HO] removes the possibility of N...Se chalcogen bonding and instead structures are obtained where the iodide and tosylate counter-ions fulfill the role of chalcogen-bond acceptors, with a strong I...Se interaction in the iodide salt and a weaker p-Tol-SO...Se interaction in the tosylate salt.
吡啶取代的苯并异硒唑啉酮 2-(吡啶-3-基)-2,3-二氢-1,2-苯并异硒唑-3-酮（CHNOSe，2）的晶体结构与抗氧化剂依布硒啉[系统名称：2-苯基-1,2-苯并异硒唑-3（2H）-酮，1]有关，其特点是存在强烈的分子间 N...Se(-N) 次价键，其中 2.3831 (6) Å 的 N...Se 距离远小于 N 和 Se 的范德华半径之和（3.34 Å）。这种强相互作用导致内部 N-Se 距离显著延长，这与 Se-N σ*反键轨道的显著占据相一致。酰胺样 O 原子与结构中极性较弱的 C-Se 键之间发生较弱的分子间 O...Se 次价键。利用高分辨率数据的多极精修对 2 进行电荷密度分析，允许绘制 2 的静电表面势能图，并清楚地揭示了 Se-N 键延伸处的 σ-hole 是正静电势能的区域。在分子中的原子量子理论（QTAIM）框架内对 2 中电子密度分布进行拓扑分析，发现 N...Se-N 部分的键路径和（3，-1）键临界点（BCP）与闭壳层相互作用一致；然而，势能项表明存在电子共享。对 2 中强 N...Se 和弱 O...Se 次价键相互作用的电子定域函数（ELF）进行分析表明，前者相互作用中存在显著的电子共享，而后者则主要是静电相互作用。2 中 N...Se 和 O...Se 次价键相互作用的电子局域函数（ELF）分析表明，前者相互作用中存在显著的电子共享，而后者则主要是静电相互作用。2 与碘甲烷（1-甲基-3-(3-氧代-2,3-二氢-1,2-苯并异硒唑-2-基)吡啶-1-鎓碘化物，CHNOSe·I）和甲基对甲苯磺酸（1-甲基-3-(3-氧代-2,3-二氢-1,2-苯并异硒唑-2-基)吡啶-1-鎓甲苯磺酸盐三水合物，CHNOSe·CHOS·3HO）反应生成其 N-甲基衍生物，排除了 N...Se 次价键的可能性，而是得到了碘化物和对甲苯磺酸盐作为次价键受体的结构，其中碘化物盐中存在强的 I...Se 相互作用，而对甲苯磺酸盐中存在较弱的 p-Tol-SO...Se 相互作用。
