Forero-Girón Angie C, Gutiérrez-Oliva Soledad, López-Alarcón Camilo, Herrera Barbara, Aliaga Margarita E
Departamento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile, 7820436.
Laboratorio de Química Teórica Computacional (QTC), Departamento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile, 7820436.
J Mol Model. 2024 Sep 17;30(10):337. doi: 10.1007/s00894-024-06132-7.
An inclusion complex between 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH), a widely employed azocompound, and cucurbit[7]util (CB[7]), has shown an increased yield of radicals derived from the homolytic cleavage of the azo bond. Aimed to get insights about the formation of complexes and their effect on the yield of radicals production, complexes of CB[7] with seven azocompounds were studied by computational methods. Molecular electrostatic surfaces and structural analysis showed that the inclusion of symmetrical azocompounds inside of CB[7] depends mainly on the charge density and position of the functional groups at the main chain of the azoderivative. Analysis of non-covalent interactions and thermodynamic outcomes revealed that positively charged azocompounds with amidinium or imidazolium groups presented strong favorable interactions (multiple hydrogen bonds) with the oxygens of CB[7] portals. Additionally, carbon-centered radicals generated from the complexes (azocompounds@CB[7]) were corroborated using the electron localization function (ELF). Results evidenced that the strength of the interactions and the level of inclusion (partial or complete) between the azocompound and CB[7] determined the final orientation of the radicals (located out- or inside of the CB[7] cavity). Obtained results could be employed to design new supramolecular systems based on the properties of azocomplound@CB[7] complexes for new scientific or industrial applications.
First-principles calculations at B3LYP-D3BJ/6-311g(d,p) level theory in the gas phase and in solvent (PCM, water) were performed in Gaussian 16 software package. The dispersion energy correction was included through the Grimme's dispersion with Becke-Johnson damping D3(BJ). Thermodynamical data and the minimum character of all structures were obtained from vibrational frequency calculations. NBO, Multiwfn, Chemcraft, and NCIPLOT software were used to perform population analysis, analyze outcomes, visualize data, and display non-covalent interactions respectively.
2,2'-偶氮二异丁脒二盐酸盐（AAPH，一种广泛使用的偶氮化合物）与葫芦[7]脲（CB[7]）之间的包合物显示出，源于偶氮键均裂产生的自由基产率有所提高。为了深入了解配合物的形成及其对自由基产生产率的影响，通过计算方法研究了CB[7]与七种偶氮化合物形成的配合物。分子静电表面和结构分析表明，对称偶氮化合物在CB[7]内部的包合主要取决于偶氮衍生物主链上官能团的电荷密度和位置。非共价相互作用和热力学结果分析表明，带有脒基或咪唑鎓基团的带正电荷的偶氮化合物与CB[7]孔道的氧原子表现出强烈的有利相互作用（多个氢键）。此外，使用电子定位函数（ELF）证实了配合物（偶氮化合物@CB[7]）产生的碳中心自由基。结果表明，偶氮化合物与CB[7]之间相互作用的强度以及包合程度（部分或完全）决定了自由基的最终取向（位于CB[7]空腔外部或内部）。所得结果可用于基于偶氮化合物@CB[7]配合物的性质设计新的超分子体系，以用于新的科学或工业应用。
在高斯16软件包中，采用B3LYP-D3BJ/6-311g(d,p)水平理论在气相和溶剂（PCM，水）中进行第一性原理计算。通过带有Becke-Johnson阻尼D3(BJ)的Grimme色散包含色散能校正。热力学数据和所有结构的极小特征是通过振动频率计算获得的。分别使用NBO、Multiwfn、Chemcraft和NCIPLOT软件进行布居分析、分析结果、可视化数据和显示非共价相互作用。
