A series of naphthalene‐diimide (NDI) and perylene‐diimide (PDI) connected bis‐N‐heterocyclic carbene complexes of iridium (III) have been prepared and fully characterized. The analysis of their NMR spectroscopic features, together their molecular structures show that these species display lone pair‐p interactions between the chloride ligands of the Ir(III) complex and the heterocycles of the NDI/PDI moieties. The detection of this type of interaction in solution is due to the formation of two atropisomers, which are formed as a result of the restricted rotation about the Ir‐Ccarbene bond imposed by the (Cl)lp…p interaction. Variable temperature 1H NMR analysis allowed to determine the strength of this non‐covalent interaction, which lies between DH = 6.6‐10 kcal/mol. The computational studies performed fully support the experimental findings. Our study demonstrates that this type of lp…p interaction is comparable to strong hydrogen bonding.

中文翻译：

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实验和计算相结合的研究揭示了孤对 p 键强度


一系列萘二酰亚胺（NDI）和苝二酰亚胺（PDI）连接的铱（III）双N杂环卡宾配合物已被制备并充分表征。对它们的 NMR 光谱特征及其分子结构的分析表明，这些物质在 Ir(III) 配合物的氯化物配体与 NDI/PDI 部分的杂环之间表现出孤对-p 相互作用。在溶液中检测到这种类型的相互作用是由于两种阻转异构体的形成，这两种阻转异构体是由于 (Cl)1p…p 相互作用所施加的 Ir-C 卡宾键旋转受限的结果而形成的。变温 1H NMR 分析可以确定这种非共价相互作用的强度，其介于 DH = 6.6-10 kcal/mol 之间。进行的计算研究完全支持实验结果。我们的研究表明，这种类型的 lp…p 相互作用与强氢键相当。