Conformational Equilibria Between Aldehydes And Alcohols: Rotational Spectra Of Acrolein-methanol And Acrolein-ethanol Complexes

Lv, Dingding

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https://hdl.handle.net/2142/111494 Copy

Description

Title

Conformational Equilibria Between Aldehydes And Alcohols: Rotational Spectra Of Acrolein-methanol And Acrolein-ethanol Complexes

Author(s)

Lv, Dingding

Contributor(s)

• Melandri, Sonia
• Maris, Assimo
• Evangelisti, Luca
• Song, Wentao

Issue Date

2021-06-23

Keyword(s)

Non-covalent interactions

Abstract

The rotational spectra of the acrolein-methanol and acrolein-ethanol complexes in gas phase were investigated with pulsed supersonic-jet Fourier-transform microwave spectroscopy and quantum mechanical calculations. Two complexes involving the s-\textit{trans} acrolein and methanol were observed, identified by methanol oxygen interacting with methylenic or aldehydic hydrogen. Two complexes involving the s-\textit{trans} acrolein and the \textit{trans} and \textit{gauche} conformations of ethanol were observed. The OD-substituted species of two conformations of s-\textit{trans}-acrolein···methanol and the OD- and $^{13}$C$_{1}$-substituted species of the s-\textit{trans}-acrolein···\textit{trans}-ethanol were measured. Ab initio calculations run at the MP2/aug-cc-pVTZ level allowed to explore the conformational space of the acrolein-alcohols complexes. The complexes involving s-\textit{cis} acrolein are less stable than those involving s-\textit{trans} acrolein, according to the energy difference in the monomer. The three-fold barriers to internal rotation of the methyl group, V$_{3}$, in s-\textit{trans}-acrolein···methanol-1 (2.629(5) kJ mol$^{-1}$) and s-\textit{trans}-acrolein···methanol-2 (2.722(5) kJ mol$^{-1}$) were determined, which are smaller than the value in methanol monomer (4.462 kJ mol$^{-1}$). Two hydrogen bonds, a conventional O-H···O and a weak C-H···O hydrogen bond, forming a planar and ring-like structure were determined in s-\textit{trans}-acrolein···methanol-1, s-\textit{trans}-acrolein···methanol-2 and s-\textit{trans}-acrolein···\textit{trans}-ethanol. Both two molecules in each complex are acting as proton donor and acceptor. Another one weak C-H···O hydrogen bond was identified in conformation s-\textit{trans} -acrolein···\textit{gauche}-ethanol, in which the acrolein oxygen interacts with the methyl and hydroxyl hydrogen of ethanol at the same time.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

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http://hdl.handle.net/2142/111494

DOI

10.15278/isms.2021.WD04

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