The role of weak C–H···O hydrogen bond in alcohol–water mixtures

Li, Tao; Fan, Wei; Sun, Jin; Yu, Yuanqin; Zhou, Xiaoguo; Xie, Chen; Liu, Shilin

doi:10.1002/jrs.6413

Cited by 4 publications

(1 citation statement)

References 66 publications

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“…Therefore, these two studies are specialized scenarios. Recently, Liu’s group reported stepwise concentration-dependent Raman frequency of alcohol–water mixtures and proposed the coexistence of the C–H···O bond with a regular O–H···O bond. , However, a simple observation of a blue-shift in aqueous solution cannot distinguish if it is an effect caused by solvent reorganization (as in an Onsager reaction field model) or a specific hyrogen-bonding interaction. Therefore, the general existence of C–H···O hydrogen bonds formed by natural C–H groups (not highly activated) in bulk aqueous solutions remains elusive.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Solvatochromism Study of the C–H···O Improper Hydrogen Bond

Shi

Min

2023

J. Phys. Chem. B

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The improper C−H•••O hydrogen bond is an important weak interaction, with broad implications for protein and nucleic acid structure, molecular recognition, enzyme catalysis, and drug interaction. Despite its wide identification in crystal structures, the general existence of C−H•••O hydrogen bonds remains elusive especially for natural C−H groups in bulk aqueous solutions at room temperature. Vibrational spectroscopy is a promising methodology to tackle this challenge, as formation of C−H•••O hydrogen bonds usually causes shifts of the C−H stretch frequency. Yet, prior observations are inconclusive, as they are all based on a simple blueshift in aqueous solution and cannot distinguish if it is an effect caused by solvent reorganization or a specific hydrogen-bonding interaction. In this work, we used vibrational solvatochromism as a calibration of the solvent reorganization effect and identified a specific H-bonding interaction. We performed vibrational solvatochromism study of C−H(D) of multiple alcohol molecules including the CH mode of CD 3 CH(OH)CD 3 and the CD 3 modes of CD 3 OH, CD 3 CH 2 OH, and CD 3 CH(OH)CD 3 in a series of solvents. We found an abnormal blue-shift of the Raman frequency of the C−H and C−D bonds at both the C α and C β positions of alcohols in water, which lies in an opposite direction to the expected trend due to vibrational solvatochromism. This experimental evidence supports that the improper C−H•••O hydrogen bonds might generally exist between nonpolarized C−H and water in liquid solutions at room temperature.

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Section: Introductionmentioning

confidence: 99%

Vibrational Solvatochromism Study of the C–H···O Improper Hydrogen Bond

Shi

Min

2023

J. Phys. Chem. B

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Machine-learning approach for prediction and analysis of quantitative and qualitative parameters of binary polar liquids

Haridas Prasanna,

Shanta

2024

Bull Mater Sci

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Roles of hydrogen bonding interactions and hydrophobic effects on enhanced water structure strength in aqueous alcohol solutions

Yang

Wang

et al. 2023

Physics of Fluids

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The structure and dynamics of water in aqueous alcohol solutions were explored using two-dimensional Raman correlation spectroscopy (2D Raman-COS) combined with density functional theory (DFT). The spectral changes in the H-O-H bending and O:H stretching modes demonstrated that ethanol and n-propanol (NPA) induced an enhancement of the water structure compared to methanol. The extent of this effect was related to the length of the alkyl chain. Comparative studies with aqueous ethylene glycol (EG) solution revealed that an enhanced water structure stemmed mainly from hydrophobic effects rather than hydrogen bonding (H-bonding) interactions. Alcohol-induced the water-specific structural transitions were further analyzed using 2D Raman-COS, which showed that the free OH and strong H-bond structure of water respond preferentially to changes in alcohol content, inducing a transition in the weak H-bond structure of water. In addition, the 2D Raman-COS results indicated that the CH3 stretching mode of alcohol responds preferentially to variations in water content compared to other C-H vibrational modes. Finally, the details of the alcohol-induced water structural transitions were calculated using DFT. The 2D Raman-COS combined with DFT calculations provided insight into alcohol-induced water structural transitions and can be easily extended to other studies of water-organic chemistry.

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The role of weak C–H···O hydrogen bond in alcohol–water mixtures

Cited by 4 publications

References 66 publications

Vibrational Solvatochromism Study of the C–H···O Improper Hydrogen Bond

Vibrational Solvatochromism Study of the C–H···O Improper Hydrogen Bond

Machine-learning approach for prediction and analysis of quantitative and qualitative parameters of binary polar liquids

Roles of hydrogen bonding interactions and hydrophobic effects on enhanced water structure strength in aqueous alcohol solutions

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