Hydrogen Bonding Interaction between Atmospheric Gaseous Amides and Methanol.

Hailiang Zhao,Lin Du,Shanshan Tang,Xiang Xu

doi:10.3390/ijms18010004

Hailiang Zhao, Lin Du + Show 2 more

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https://doi.org/10.3390/ijms18010004

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Abstract

Amides are important atmospheric organic–nitrogen compounds. Hydrogen bonded complexes of methanol (MeOH) with amides (formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide and N,N-dimethylacetamide) have been investigated. The carbonyl oxygen of the amides behaves as a hydrogen bond acceptor and the NH group of the amides acts as a hydrogen bond donor. The dominant hydrogen bonding interaction occurs between the carbonyl oxygen and the OH group of methanol as well as the interaction between the NH group of amides and the oxygen of methanol. However, the hydrogen bonds between the CH group and the carbonyl oxygen or the oxygen of methanol are also important for the overall stability of the complexes. Comparable red shifts of the C=O, NH- and OH-stretching transitions were found in these MeOH–amide complexes with considerable intensity enhancement. Topological analysis shows that the electron density at the bond critical points of the complexes fall in the range of hydrogen bonding criteria, and the Laplacian of charge density of the O–H∙∙∙O hydrogen bond slightly exceeds the upper value of the Laplacian criteria. The energy decomposition analysis further suggests that the hydrogen bonding interaction energies can be mainly attributed to the electrostatic, exchange and dispersion components.

Highlights

Amides have attracted great attention due to their importance to N–H···O hydrogen bonding interaction in determining the structures and properties of biological systems, such as the interactions between protein and polypeptides [1,2,3]
The results revealed that the observed complexes may be precursors in the atmospheric sulfate and bisulfate cluster formation
Previous studies demonstrated that the trans-form was more stable in the gas phase [28,29,30], which is consistent with our study: trans-NMF > cis-NMF by 4.8 kJ·mol−1 (B3LYP-D3/aug-cc-pVTZ, corrected with zero point vibrational energy (ZPVE)) and trans-NMA > cis-NMA by 9.7 kJ·mol−1 (B3LYP-D3/aug-cc-pVTZ, corrected with ZPVE)

Summary

Introduction

Amides have attracted great attention due to their importance to N–H···O hydrogen bonding interaction in determining the structures and properties of biological systems, such as the interactions between protein and polypeptides [1,2,3]. Amide is a simplified example of peptide linkage, which allows studying both hydrophobic and hydrophilic interactions. Amides have been widely observed in the atmosphere [4]. Amides are emitted from a variety of natural and anthropogenic sources including agriculture, biomass burning, animal husbandry, cooking, synthetic leather, carbon capture, and other industrial processes [4,5,6]. FA was detected in the emissions from an industrial carbon capture facility via degradation of mono-ethanolamine, using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) [5]. Amides can be formed by the degradation of amines [6]. Amide in the atmosphere can react with OH radicals, and lead to gaseous degradation products and formation of secondary organic aerosols [7,9]

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