Vibrational spectra of mono-, di- and trichloroacetamide and mono- and trifluoroacetamide

Troitiño, D.; Blanca, E. Sánchez de la; García, M.J.

doi:10.1016/0584-8539(90)80131-h

Cited by 11 publications

(2 citation statements)

References 22 publications

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“…The two observed bands in this IR region correspond unequivocally to the vibrational transitions of TFAm, since the different cations of the HBAs do not have vibrational transitions in this part of the spectrum (see Supporting Information, Figures S1 and S2). Furthermore, the strong absorption at 1724 cm –1 and a weak band at 1625 cm –1 have been previously assigned to the amide mode and the scissoring mode of the amide hydrogens of TFAm, respectively . Overall, the amide band of the different samples shows a similar and slightly asymmetric line shape, and it is not well modeled with a single Voight profile.…”

Section: Resultsmentioning

confidence: 88%

“…Furthermore, the strong absorption at 1724 cm −1 and a weak band at 1625 cm −1 have been previously assigned to the amide mode and the scissoring mode of the amide hydrogens of TFAm, respectively. 56 Overall, the amide band of the different samples shows a similar and slightly asymmetric line shape, and it is not well modeled with a single Voight profile. Moreover, the line shape is significantly different when the TFAm molecule is isolated (see Supporting Information, Figure S3), which is consistent with the presence of a vibrational exciton.…”

Section: ■ Resultsmentioning

confidence: 92%

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Evidence of Molecular Heterogeneities in Amide-Based Deep Eutectic Solvents

Cui

Kuroda

2018

J. Phys. Chem. A

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The liquid structure of five different amide-based deep eutectic solvents (DESs) as a function of the chemical structure of the hydrogen bond acceptor (HBA) was investigated by linear Fourier transform infrared (FTIR) and two-dimensional infrared (2DIR) spectroscopies. Linear FTIR spectroscopy shows that the amide band of the DESs is not significantly affected by the chemical structure and symmetry of the HBA cation. However, its excitonic nature does not allow us to draw further conclusions. Analysis of the C amide line shapes derived from the 2DIR spectra reveals that the different DESs do not show appreciable differences in the level of disorganization. The vibrational dynamics, derived from the photon echo experiments on theC amide, shows that there is a fast component with a time scale of ∼1 ps irrespective of the HBA. The ultrafast dynamics is assigned to hydrogen bond making and breaking between amides. In addition, a slow dynamical component is observed in the time evolution of the photon echo signal. This contribution appears to be correlated with the asymmetry and polarity of the moieties of the HBA. The overall dynamics is rationalized in terms of a microscopic heterogeneous structure of the DESs, where the heterogeneities create domains that slow the hydrogen bond making and breaking. Molecular dynamics simulations provide additional support for our modeling of the data. In addition, the presence of nanoscopic heterogeneities is consistent with the observation of an endortherm at 23 °C in the differential scanning calorimetry thermogram, which evidenced a phase transition at 23 °C, even though the tested DESs have a melting temperature below -40 °C.

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Section: Resultsmentioning

confidence: 88%

Section: ■ Resultsmentioning

confidence: 92%