Structural and Electronic Evolution of Ethanolamine upon Microhydration: Insights from Hyperfine Resolved Rotational Spectroscopy

TY - JOUR

T1 - Structural and Electronic Evolution of Ethanolamine upon Microhydration

T2 - Insights from Hyperfine Resolved Rotational Spectroscopy

AU - Xie, Fan

AU - Mendolicchio, Marco

AU - Omarouayache, Wafaa

AU - Murugachandran, S. Indira

AU - Lei, Juncheng

AU - Gou, Qian

AU - Sanz, M. Eugenia

AU - Barone, Vincenzo

AU - Schnell, Melanie

N1 - Publisher Copyright: © 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

PY - 2024/9/2

Y1 - 2024/9/2

N2 - Ethanolamine hydrates containing from one to seven water molecules were identified via rotational spectroscopy with the aid of accurate quantum chemical methods considering anharmonic vibrational corrections. Ethanolamine undergoes significant conformational changes upon hydration to form energetically favorable hydrogen bond networks. The final structures strongly resemble the pure (H2O)3–9 complexes reported before when replacing two water molecules by ethanolamine. The 14N nuclear quadrupole coupling constants of all the ethanolamine hydrates have been determined and show a remarkable correlation with the strength of hydrogen bonds involving the amino group. After addition of the seventh water molecule, both hydrogen atoms of the amino group actively contribute to hydrogen bond formation, reinforcing the network and introducing approximately 21–27 % ionicity towards the formation of protonated amine. These findings highlight the critical role of microhydration in altering the electronic environment of ethanolamine, enhancing our understanding of amine hydration dynamics.

AB - Ethanolamine hydrates containing from one to seven water molecules were identified via rotational spectroscopy with the aid of accurate quantum chemical methods considering anharmonic vibrational corrections. Ethanolamine undergoes significant conformational changes upon hydration to form energetically favorable hydrogen bond networks. The final structures strongly resemble the pure (H2O)3–9 complexes reported before when replacing two water molecules by ethanolamine. The 14N nuclear quadrupole coupling constants of all the ethanolamine hydrates have been determined and show a remarkable correlation with the strength of hydrogen bonds involving the amino group. After addition of the seventh water molecule, both hydrogen atoms of the amino group actively contribute to hydrogen bond formation, reinforcing the network and introducing approximately 21–27 % ionicity towards the formation of protonated amine. These findings highlight the critical role of microhydration in altering the electronic environment of ethanolamine, enhancing our understanding of amine hydration dynamics.

KW - Conformations

KW - Hydrogen bond

KW - Microhydration

KW - Nuclear quadrupole coupling

KW - Rotational spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85202917518&partnerID=8YFLogxK

U2 - 10.1002/anie.202408622

DO - 10.1002/anie.202408622

M3 - Article

SN - 1433-7851

VL - 63

SP - e202408622

JO - Angewandte Chemie - International Edition

JF - Angewandte Chemie - International Edition

IS - 40

M1 - e202408622

ER -