Relationship between the Broad OH Stretching Band of Methanol and Hydrogen-Bonding Patterns in the Liquid Phase

Ohno, Keiichi; Shimoaka, Takafumi; Akai, Nobuyuki; Katsumoto, Yukiteru

doi:10.1021/jp800995m

Cited by 82 publications

(67 citation statements)

References 38 publications

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“…5(b). 69 Let us now turn to the thermal evolution of the polyalcohol spectra. Near 1575 nm an absorbance peak is observed for propylene glycol and glycerol which strongly grows in intensity with decreasing temperatures.…”

Section: Near-infrared Spectroscopymentioning

confidence: 99%

Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy

Sillrén

Matic

Karlsson

et al. 2014

The Journal of Chemical Physics

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Liquid monohydroxy alcohols exhibit unusual dynamics related to their hydrogen bonding induced structures. The connection between structure and dynamics is studied for liquid 1-propanol using quasi-elastic neutron scattering, combining time-of-flight and neutron spin-echo techniques, with a focus on the dynamics at length scales corresponding to the main peak and the pre-peak of the structure factor. At the main peak, the structural relaxation times are probed. These correspond well to mechanical relaxation times calculated from literature data. At the pre-peak, corresponding to length scales related to H-bonded structures, the relaxation times are almost an order of magnitude longer. According to previous work [C. Gainaru, R. Meier, S. Schildmann, C. Lederle, W. Hiller, E. Rössler, and R. Böhmer, Phys. Rev. Lett. 105, 258303 (2010)] this time scale difference is connected to the average size of H-bonded clusters. The relation between the relaxation times from neutron scattering and those determined from dielectric spectroscopy is discussed on the basis of broad-band permittivity data of 1-propanol. Moreover, in 1-propanol the dielectric relaxation strength as well as the near-infrared absorbance reveal anomalous behavior below ambient temperature. A corresponding feature could not be found in the polyalcohols propylene glycol and glycerol.

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Section: Near-infrared Spectroscopymentioning

confidence: 99%

Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy

Sillrén

Matic

Karlsson

et al. 2014

The Journal of Chemical Physics

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“…Thus, both OH…OH and C=O…HO types of hydrogen-bonds are acceptable in PHEMA. Not only dimer structure (OH…OH) but also aggregates structure (…OH…OH…OH…) have been found in many systems including liquid alcohols (Kristiansson, 1999; Ohno et al, 2008) and solid polymers (Morita et al, 2008, 2009). Such the hydrogen-bonds structure in polymers plays important roles for their macromolecular functions in artificial polymers (Brunsveld et al, 2001) as well as biopolymers (Watanabe et al, 2006, 2007).…”

Section: Introductionmentioning

confidence: 99%

Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) studied by temperature-dependent infrared spectroscopy

Morita

2014

Front. Chem.

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Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated by means of temperature-dependent infrared (IR) spectroscopy. Spectral variations involved with the OH…OH and C=O…HO types of hydrogen-bonds were found around the glass transition temperature of 80°C. Hydrogen-bonds among the hydroxyl groups gradually dissociate with increasing temperature. In contrast, discontinuous variation in the carbonyl bands was observed around the glass transition temperature. An association of the C=O…HO type of hydrogen-bond with increasing temperature above the glass transition temperature was revealed. These were concluded from the present study that hydrogen-bonds among the hydroxyl groups in each side chain terminal suppress the main chain mobility in the polymer matrix below the glass transition temperature, while the dissociation of the OH…OH type of hydrogen-bonds induces the association of the C=O…HO type of hydrogen-bond. As a result, the mobility of the main chain is induced by the change in hydrogen-bonds structure at the glass transition temperature.

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“…[4] Less stability of branched cyclic structures has been previously found in methanol clusters. [45][46][47][48][49][50][51] Generally, the relative stability of the structures of the ethanol hexamer reported in this work follow the same trend as that of the methanol clusters. Although branched cyclic structures are among the less stable structures, among all the investigated structures of the ethanol hexamer, the flat cyclic hexamer comprising six trans monomers is found to be the least stable (see Figure 3).…”

Section: Structures and Relative Probabilitiesmentioning

confidence: 70%

Theoretical infrared spectrum of the ethanol hexamer

Malloum

Fifen

Conradie

2020

Int J of Quantum Chemistry

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The hydrogen bond network of ethanol clusters is among the most complex hydrogen bond networks of molecular clusters. One of the reasons of its complexity arises from the number of possible ethanol monomers (there are three isoenergetic isomers of the ethanol monomer). This leads to difficulties in the exploration of potential energy surfaces (PESs) of ethanol clusters. In this work, we have explored the PES of the ethanol hexamer at the MP2/aug-cc-pVDZ level of theory. We have provided structures and their relative stability at 0 K and for temperatures ranging from 20 to 400 K in the gas phase. These structures are used to compute the theoretical infrared (IR) spectrum of the ethanol hexamer at the MP2/aug-cc-pVDZ level of theory. As a result, 98 different structures have been investigated, and six isomers are reported to be the most isoenergetically stable structures of the ethanol hexamer. These isomers are folded cyclic structures in which the stability is enhanced by the implication of CHÁ Á ÁO interactions. Our investigations show that the PES of the ethanol hexamer is very flat, yielding several isoenergetic structures. Furthermore, we have noted that several isomers contribute to the population of the ethanol hexamer at high temperatures. As far as the IR spectroscopic study is concerned, we have found that the IR spectra of the most stable structures are in good agreement with the experiment.Considering this agreement, these structures are used to assign the experimental peaks in the CH-stretching region. We concluded that the stability of the structures of the ethanol hexamer is related both to OHÁ Á ÁO hydrogen bonds and CHÁ Á ÁO interactions. Overall, we have found that the IR spectrum of the ethanol hexamer, calculated from the contribution of all the possible stable structures weighted by their probability, excellently reproduce the experimental spectrum of the ethanol hexamer. K E Y W O R D S ethanol clusters, ethanol hexamer, infrared spectrum, relative population, Voigt profile 1 | INTRODUCTIONLiquid ethanol has important applications in industries, and it is widely used as a solvent in chemical processes. Besides, ethanol has many applications in medicine and pharmacology. [1] Understanding of some properties of liquid ethanol is related to the hydrogen bond networks of ethanol clusters (EtOH) n . The hydrogen bond networks of the ethanol clusters are among the most complex hydrogen bond networks in molecular clusters. One of the reasons of this complexity is the high number of possible stable structures of the ethanol monomer (there are three isoenergetic isomers of the ethanol monomer: gauche−, trans, and gauche+ related to the value of the CCOH dihedral angles −60 , 180 , and +60 , respectively). [2][3][4] Most of the investigations performed on ethanol clusters are limited to the ethanol dimer due to difficulties arising from the exploration of the potential energy surfaces (PESs) of the ethanol clusters. [2,3,[5][6][7][8][9][10][11] Reliable investigations performed on the ethanol dimer,

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Relationship between the Broad OH Stretching Band of Methanol and Hydrogen-Bonding Patterns in the Liquid Phase

Cited by 82 publications

References 38 publications

Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy

Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy

Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) studied by temperature-dependent infrared spectroscopy

Theoretical infrared spectrum of the ethanol hexamer

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