Khera Mayank, Goel Neetu
Computational and Theoretical Chemistry Group, Department of Chemistry & Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India.
J Phys Chem A. 2023 Aug 24;127(33):6953-6961. doi: 10.1021/acs.jpca.3c04110. Epub 2023 Aug 9.
Density functional theory investigation of regium (Rg)-π bonding using the RgL-X model system, where Rg = Cu and Ag; L = CN, NO, and OH; X = π-conjugated system (benzene, cyanobenzene, benzoic acid, pyridine, 2-methoxy aniline, 1,4-dimethoxy benzene, and cyclophane), has been performed. Conclusive evidence of the Rg-π bond has been provided by analysis of molecular electrostatic potential surfaces, Rg-π bond length, interaction energy (Δ), second-order perturbation energy (), charge transfer (Δ), quantum theory of atom in molecules, and noncovalent interaction plots for 42 structural arrangements with varying ligands and the substituted aromatic ring. The Rg-π bond length in the optimized model systems varies from 2.03 to 2.12 Å in Cu complexes (-) and from 2.26 to 2.38 Å in Ag complexes (-) at the PBE0-D3 functional. While the ligand (L) attached to the Rg metal has a bargaining effect on the strength of the Rg-π bond (in the order of -OH > -CN = -NO), the π-conjugated systems have a diminutive effect. Two X-ray crystal structures (CUCSOI and AHIDQU) having the Rg-π bond, accessed from Cambridge Crystallographic Data Centre (CCDC), are discussed here to signify the influence of Rg-π bonding on the crystal structure.
利用RgL-X模型体系对regium（Rg）-π键进行密度泛函理论研究，其中Rg = Cu和Ag；L = CN、NO和OH；X = π共轭体系（苯、氰苯、苯甲酸、吡啶、2-甲氧基苯胺、1,4-二甲氧基苯和环芳烷）。通过对分子静电势表面、Rg-π键长、相互作用能（Δ）、二阶微扰能（）、电荷转移（Δ）、分子中原子的量子理论以及42种具有不同配体和取代芳环的结构排列的非共价相互作用图进行分析，提供了Rg-π键的确凿证据。在PBE0-D3泛函下，优化模型体系中Cu配合物（-）的Rg-π键长在2.03至2.12 Å之间变化，Ag配合物（-）的Rg-π键长在2.26至2.38 Å之间变化。虽然连接到Rg金属上的配体（L）对Rg-π键的强度有影响（顺序为-OH > -CN = -NO），但π共轭体系的影响较小。本文讨论了从剑桥晶体学数据中心（CCDC）获取的两个具有Rg-π键的X射线晶体结构（CUCSOI和AHIDQU），以表明Rg-π键对晶体结构的影响。
