Hydrogen bond and the resonance effect on the formamide–water complexes

Parreira, Renato L. T.; Caramori, Giovanni F.; Morgon, Nelson H.; Galembeck, Sérgio E.

doi:10.1002/qua.23124

Cited by 4 publications

(1 citation statement)

References 103 publications

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“…Another factor that bears on the correlation between the two scales is that we employed solvents of very different classes, i.e., solvents that interact with each other (Hildebrand/Hansen) and with the probe (solvatochromism) by different mechanisms. Examples are formamide that is involved in extensive hydrogen bonded networks, the strongly dipolar DMSO, , the strongly dipolar bidendate sulfolane, and weakly interacting solvents such as halogenated hydrocarbons and nonpolar ones such as hydrocarbons.…”

Section: Results and Discussionmentioning

confidence: 99%

Solvatochromic and Solubility Parameters of Solvents: Equivalence of the Scales and Application to Probe the Solubilization of Asphaltenes

et al. 2016

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The oil compatibility model is important for assessing the stability of crudes. The compatibility between maltenes and the corresponding asphaltenes, Asphs, can be assessed from the solubility parameters (Hildebrand and Hansen) of both components of the crude. Solvatochromism is the effect of the medium on the UV/vis spectra of substances (solvatochromic probes) that are sensitive to the properties of the medium, namely, its empirical (or overall) polarity, Lewis acidity and basicity, dipolarity, and polarizability. Therefore, the solubility and solvatochromic parameters of solvents should be related. We synthesized a novel solvatochromic probe (E-2,6-di-tert-butyl-4-(2-(1-hexylquinolin-1-ium-4-yl)vinyl)phenolate, HxQMBu 2 ) whose properties are convenient to study in nonpolar and polar solvents. The empirical solvent polarities measured with HxQMBu 2 in 38 solvents correlated linearly with the corresponding Hildebrand solubility parameters. Likewise, the solvent Lewis acidity/basicity, dipolarity, and polarizability correlated linearly with the corresponding Hansen solubility parameters. To test the equivalence of the two scales (solvatochromic and solubility parameters), we determined the solubility of Asphs in 28 solvents, pertaining to different chemical classes. The dependence of Asph solubility on three solvent descriptors (Lewis acidity/basicity, dipolarity, and polarizability) was tested. Our results indicated that alcohols and hydrocarbons are inefficient solvents; solvents of intermediate efficiency carry either a strongly dipolar group or polarized bonds. Aromatic and heterocyclic solvents are most efficient. The most relevant solvent descriptor (for the dissolution of Asphs) is its polarizability.

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Section: Results and Discussionmentioning

confidence: 99%

Solvatochromic and Solubility Parameters of Solvents: Equivalence of the Scales and Application to Probe the Solubilization of Asphaltenes

et al. 2016

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Cooperativity of intermolecular hydrogen bonds in microsolvated DMSO and DMF clusters: a DFT, AIM, and NCI analysis

Venkataramanan

2016

J Mol Model

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Density functional theory (DFT) calculations are performed to study the hydrogen-bonding in the DMSO-water and DMF-water complexes. Quantitative molecular electrostatic potential (MESP) and atoms-in-molecules (AIM) analysis are applied to quantify the relative complexation of DMSO and DMF with water molecules. The interaction energy of DMSO with water molecules was higher than in DMF-water complexes. The existence of cooperativity effect helps in the strong complex formation. A linear dependence was observed between the hydrogen bond energies EHB, and the total electron densities in the BCP's of microsolvated complexes which supports the existence of cooperativity effect for the complexation process. Due to the stronger DMSO/DMF and water interaction, the water molecules in the formed complexes have a different structure than the isolated water clusters. NCI analysis shows that the steric area is more pronounced in DMF-water complex than the DMSO-water complex which accounts for the low stability of DMF-water complexes compared to the DMSO-water complex. Graphical abstract NCI analysis shows that the steric area is more pronounced in DMF-water complex than the DMSO-water complex which accounts for the low stability of DMF-water complexes compared to the DMSO-water complex.

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The effect of intermolecular hydrogen bonding on the planarity of amides

Platts

Maarof

Harris

et al. 2012

Phys. Chem. Chem. Phys.

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Ab initio and density functional theory (DFT) calculations on some model systems are presented to assess the extent to which intermolecular hydrogen bonding can affect the planarity of amide groups. Formamide and urea are examined as archetypes of planar and non-planar amides, respectively. DFT optimisations suggest that appropriately disposed hydrogen-bond donor or acceptor molecules can induce non-planarity in formamide, with OCNH dihedral angles deviating by up to ca. 201 from planarity. Ab initio energy calculations demonstrate that the energy required to deform an amide molecule from the preferred geometry of the isolated molecule is more than compensated by the stabilisation due to hydrogen bonding. Similarly, the NH 2 group in urea can be made effectively planar by the presence of appropriately positioned hydrogen-bond acceptors, whereas hydrogen-bond donors increase the non-planarity of the NH 2 group. Small clusters (a dimer, two trimers and a pentamer) extracted from the crystal structure of urea indicate that the crystal field acts to force planarity of the urea molecule; however, the interaction with nearest neighbours alone is insufficient to induce the molecule to become completely planar, and longer-range effects are required. Finally, the potential for intermolecular hydrogen bonding to induce non-planarity in a model of a peptide is explored. Inter alia, the insights obtained in the present work on the extent to which the geometry of amide groups may be deformed under the influence of intermolecular hydrogen bonding provide structural guidelines that can assist the interpretation of the geometries of such groups in structure determination from powder X-ray diffraction data.

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Hydrogen bond and the resonance effect on the formamide–water complexes

Cited by 4 publications

References 103 publications

Solvatochromic and Solubility Parameters of Solvents: Equivalence of the Scales and Application to Probe the Solubilization of Asphaltenes

Solvatochromic and Solubility Parameters of Solvents: Equivalence of the Scales and Application to Probe the Solubilization of Asphaltenes

Cooperativity of intermolecular hydrogen bonds in microsolvated DMSO and DMF clusters: a DFT, AIM, and NCI analysis

The effect of intermolecular hydrogen bonding on the planarity of amides

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