A comparison of non-covalent interactions in the crystal structures of two s-alkane complexes of Rh exhibiting contrasting stabilities in the solid state
A comparison of non-covalent interactions in the crystal structures of two s-alkane complexes of Rh exhibiting contrasting stabilities in the solid state
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Rh 的两种 s-烷烃配合物晶体结构中非共价相互作用的比较，表现出不同的固态稳定性
DOI：
10.1039/d3fd00009e
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发表时间：
2023
影响因子：
3.4
通讯作者：
Sajjad M
中科院分区：
文献类型：
--
作者：
Sajjad M
本文研究了Rh σ-烷烃阳离子配合物的非共价相互作用。（Cy2PCH2CH2PCy2）Rh（NBA）][BArF4]，[1-NBA][BArF4]（NBA =正庚烷，C7 H12; ArF = 3，5-（CF 3）2C 6 H3）和[1-丙烷][BArF 4]进行了分析，使用原子在分子中的量子理论（QTAIM）和独立梯度模型方法，后者在Hirshfeld分区方案（IGMH）下。在这两种结构中，阳离子都存在于[BArF 4]−阴离子的八面体阵列中，其中[1-NBA]+阳离子系统与阴离子的接触数量更多。QTAIM和IGMH分析表明，这些系统中的阳离子和阴离子之间存在最强的单个原子-原子非共价相互作用。IGMH方法突出了这些C-H F接触的方向性，与更扩散的C-H π相互作用形成对比。后者的累积效应导致更显著的稳定贡献。IGMH %δGatom图提供了一个特别有用的可视化工具，用于识别关键相互作用，并突出丙烷和NBA配体（后者为截短的-{C3 H4}-单元）以及膦取代基的环己基环中存在的-{C3 H6}-丙烯部分的重要性。讨论了这一点作为一个特权基序赋予固态σ-烷烃复合物的晶体结构稳定性的潜力。[1-NBA][BArF 4]系统中C-H F离子间相互作用的数量越多，加上C-H π相互作用越显著，这与[1-NBA]+阳离子周围的非共价稳定性越高一致。这也得到了更大的计算δGatom指数作为阳离子-阴离子非共价相互作用能的量度的支持。
Non-covalent interactions surrounding the cationic Rh σ-alkane complexes within the crystal structures of [(Cy2PCH2CH2PCy2)Rh(NBA)][BArF4], [1-NBA][BArF4] (NBA = norbornane, C7H12; ArF = 3,5-(CF3)2C6H3), and [1-propane][BArF4] are analysed using Quantum Theory of Atoms in Molecules (QTAIM) and Independent Gradient Model approaches, the latter under a Hirshfeld partitioning scheme (IGMH). In both structures the cations reside in an octahedral array of [BArF4]− anions within which the [1-NBA]+ cation system exhibits a greater number of C–H⋯F contacts to the anions. QTAIM and IGMH analyses indicate these include the strongest individual atom–atom non-covalent interactions between the cation and the anion in these systems. The IGMH approach highlights the directionality of these C–H⋯F contacts that contrasts with the more diffuse C–H⋯π interactions. The accumulative effects of the latter lead to a more significant stabilizing contribution. IGMH %δGatom plots provide a particularly useful visual tool to identify key interactions and highlight the importance of a –{C3H6}– propylene moiety that is present within both the propane and NBA ligands (the latter as a truncated –{C3H4}– unit) and the cyclohexyl rings of the phosphine substituents. The potential for this to act as a privileged motif that confers stability on the crystal structures of σ-alkane complexes in the solid-state is discussed. The greater number of C–H⋯F inter-ion interactions in the [1-NBA][BArF4] system, coupled with more significant C–H⋯π interactions are all consistent with greater non-covalent stabilisation around the [1-NBA]+ cation. This is also supported by larger computed δGatom indices as a measure of cation–anion non-covalent interaction energy.