Conformational equilibria in acrolein-CO: the crucial contribution of n → π interactions unveiled by rotational spectroscopy

• Published in: Physical chemistry chemical physics : PCCP 2024-07, Vol.26 (27), p.18865-1887
• Main Authors: Wang, Hao, Chen, Junhua, Tian, Xiao, Wang, Chenxu, Lan, Junlin, Liu, Xingchen, Zhang, Zhenhua, Wen, Xiaodong, Gou, Qian
• Format: Article
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d4cp01650e

Using gas phase Fourier-transform microwave spectroscopy complemented by theoretical analysis, this study delivers a comprehensive depiction of the physical origin of the 'n → π* interaction' between CO 2 and acrolein, one of the most reactive aldehydes. Three distinct isomers of the acrolein-CO 2 complex, linked through a C O tetrel bond (or n → π* interaction) and a C-H O hydrogen bond, have been unambiguously identified in the pulsed jet. Relative intensity measurements allowed estimation on the population ratio of the three isomers to be T1 / T2 / C1 25/5/1. Advanced theoretical analyses were employed to elucidate the intricacies of the noncovalent interactions within the examined complex. This study not only sheds light on the molecular underpinnings of n → π* interactions but also paves the way for future exploration in carbon dioxide capture and utilization, leveraging the fundamental principles uncovered in the study of acrolein-carbon dioxide interactions. Using Fourier-transform microwave spectroscopy complemented by theoretical analysis, this study delivers a comprehensive depiction of the physical origin of the 'n → π* interaction' between CO 2 and acrolein.