School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331 Chongqing, China.
Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, Paseo de Belén 7, 47011 Valladolid, Spain.
J Chem Phys. 2023 Mar 28;158(12):124304. doi: 10.1063/5.0144298.
The non-covalent bonding features of carbonyl-carbonyl interactions have been investigated in the dimer of formaldehyde and trifluoroacetone using high resolution rotational spectroscopy combined with quantum chemical calculations. The observation of all possible isotopic substitutions for the heavy atoms in the complex enabled the determination of the accurate structure, characterized by the antiparallel arrangement of the two C=O bonds. The two moieties are connected through a dominant n → π* interaction enhanced by one weak C-H⋯O hydrogen bond, as revealed by supporting natural bond orbital analysis and symmetry-adapted perturbation theory analysis. Further computational investigations on 17 related adducts stabilized by carbonyl-carbonyl n → π* interactions show how the interaction strength is regulated by the incorporation of either electron-donating or withdrawing functional groups.
采用高分辨率旋转光谱学结合量子化学计算研究了甲醛和三氟丙酮二聚体中羰基-羰基相互作用的非共价键合特征。通过观察复合物中重原子的所有可能同位素取代，确定了准确的结构，特征为两个 C=O 键的反平行排列。两个部分通过主导的 n → π* 相互作用连接，该相互作用由一个较弱的 C-H⋯O 氢键增强，这一点通过支持自然键轨道分析和对称自适应微扰理论分析得到揭示。通过对 17 个由羰基-羰基 n → π* 相互作用稳定的加合物的进一步计算研究，揭示了如何通过引入供电子或吸电子官能团来调节相互作用强度。
