Interaction energy and the shift in OH stretch frequency on hydrogen bonding for the H2O → H2O, CH3OH → H2O, and H2O → CH3OH dimers

2009 ◽  
pp. NA-NA ◽  
Author(s):  
Richard Kramer Campen ◽  
James D. Kubicki
Keyword(s):  
Hydrogen Bonding ◽  
Interaction Energy

Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals

2021 ◽  
Author(s):  
Thufail M. Ismail ◽  
Neetha Mohan ◽  
P. K. Sajith
Keyword(s):  
Hydrogen Bonding ◽  
Interaction Energy ◽  
Electrostatic Potential ◽  
Molecular Electrostatic Potential ◽  
Theoretical Study ◽  
Nitroxide Radicals ◽  
Hydrogen Bonding Interactions ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Interaction energy (Eint) of hydrogen bonded complexes of nitroxide radicals can be assessed in terms of the deepest minimum of molecular electrostatic potential (Vmin).

scholarly journals Intermolecular Non-Covalent Carbon-Bonding Interactions with Methyl Groups: A CSD, PDB and DFT Study

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3370 ◽  
Author(s):  
Tiddo J. Mooibroek
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Dft Calculations ◽  
Interaction Energy ◽  
Weak Interaction ◽  
Systematic Evaluation ◽  
Methyl Groups ◽  
Interaction Energies ◽  
Hydrogen Bonding Interactions ◽  
Carbon Bonding

A systematic evaluation of the CSD and the PDB in conjunction with DFT calculations reveal that non-covalent Carbon-bonding interactions with X–CH3 can be weakly directional in the solid state (P ≤ 1.5) when X = N or O. This is comparable to very weak CH hydrogen bonding interactions and is in line with the weak interaction energies calculated (≤ –1.5 kcal·mol−1) of typical charge neutral adducts such as [Me3N-CH3···OH2] (2a). The interaction energy is enhanced to ≤–5 kcal·mol−1 when X is more electron withdrawing such as in [O2N-CH3··O=Cdme] (20b) and to ≤18 kcal·mol−1 in cationic species like [Me3O+-CH3···OH2]+ (8a).

scholarly journals A third-generation dispersion and third-generation hydrogen bonding corrected PM6 method: PM6-D3H+

2014 ◽  
Author(s):  
Jimmy Charnley Kromann ◽  
Anders Christensen ◽  
Casper Steinmann ◽  
Martin Korth ◽  
Jan H. Jensen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Interaction Energy ◽  
Vibrational Analysis ◽  
Attractive Alternative ◽  
Third Generation ◽  
Dispersion Correction ◽  
Free Energies ◽  
Small Proteins

We present new dispersion and hydrogen bond corrections to the PM6 method, PM6-D3H+, and its implementation in the GAMESS program. The method combines the DFT-D3 dispersion correction by Grimme et al with a modified version of the H+ hydrogen bond correction by Korth. Overall, the interaction energy of PM6-D3H+ is very similar to PM6-DH2 and PM6-DH+, with RMSD and MAD values within 0.02 kcal/mol of one another. The main difference is that the geometry optimizations of 88 complexes result in 82, 6, 0, and 0 geometries with 0, 1, 2, and $\ge$ 3 imaginary frequencies using PM6-D3H+ implemented in GAMESS, while the corresponding numbers for PM6-DH+ implemented in MOPAC are 54, 17, 15, and 2. The PM6-D3H+ method as implemented in GAMESS offers an attractive alternative to PM6-DH+ in MOPAC in cases where the LBFGS optimizer must be used and a vibrational analysis is needed, e.g. when computing vibrational free energies. While the GAMESS implementation is up to 10 times slower for geometry optimizations of proteins in bulk solvent, compared to MOPAC, it is sufficiently fast to make geometry optimizations of small proteins practically feasible.

Exploring the rare S—H...S hydrogen bond using charge density analysis in isomers of mercaptobenzoic acid

2017 ◽  
Vol 73 (4) ◽  
pp. 626-633 ◽  
Author(s):  
Mysore. S Pavan ◽  
Sounak Sarkar ◽  
Tayur N. Guru Row
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Charge Density ◽  
Interaction Energy ◽  
Electron Density ◽  
Type I ◽  
Weak Hydrogen Bond ◽  
Topological Features ◽  
Density Analysis ◽  
Density Study

Experimental and theoretical charge density analyses on isomers of mercaptobenzoic acid have been carried out to quantify the hydrogen bonding of the hitherto less explored thiols, to assess the strength of the interactions using the topological features of the electron density. The electron density study offers interesting insights into the nature of the S—H...S interaction. The interaction energy is comparable with that of a weak hydrogen bond. The strength and directionality of the S—H...S hydrogen bond is demonstrated to be mainly due to the conformation locking potential of the intramolecular S...O chalcogen bond in 2-mercaptobenzoic acid and is stronger than in 3-mercaptobenzoic acid, which lacks the intramolecular S...O bond. Thepara-substituted mercaptobenzoic acid depicts a type I S...S interaction.

scholarly journals Supramolecular Approach to Tuning the Photophysical Properties of Quadrupolar Squaraines

2022 ◽  
Vol 9 ◽  
Author(s):  
Anna Kaczmarek-Kȩdziera ◽  
Borys Ośmiałowski ◽  
Piotr S. Żuchowski ◽  
Dariusz Kȩdziera
Keyword(s):  
Hydrogen Bonding ◽  
Interaction Energy ◽  
Cross Section ◽  
Photophysical Properties ◽  
Strong Support ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Three Body ◽  
Absorption Wavelength

In the present study, the influence of the hydrogen bonding for the one- and two-photon absorption of the prototypical squaraine dye is investigated with quantum chemistry tools. The central squaraine unit is bound by strong hydrogen bonds with 4-substituted N,N′-diphenylurea and, alternatively, N,N′-diphenylthiourea molecules, which affects to a high extend the properties of the squaraine electron accepting moiety, thus shifting its maximum absorption wavelength and enhancing the TPA cross section. The replacement of oxygen by sulfur atoms in the squaraine central ring, known to affect its photophysical behavior, is considered here as the way of modifying the strength and nature of the intermolecular contacts. Additionally, the influence of the oxygen-by-sulfur replacement is also considered in the N,N′-diphenylurea moiety, as the factor affecting the acidity of the N–H protons. The introduction of the sequence of the substituents of varying electron-donating or electron-withdrawing characters in the position 4 of N,N′-diphenyl(thio)urea subsystems allows to finely tune the hydrogen bonding with the central squaraine unit by further modification of the N–H bond characteristics. All of these structural modifications lead to the controlled adjustment of the electron density distribution, and thus, the properties affected such as transition moments and absorption intensity. Ab initio calculations provide strong support for this way of tailoring of one- or two-photon absorption due to the obtained strong hypsochromic shift of the maximum one-photon absorption wavelength observed particularly for thiosquaraine complexes and an increase in the TPA wavelength together with the increase in the TPA cross section. Moreover, the source of the strong modification of the thiosquaraine OPA in contrast to the pristine oxosquaraine upon N,N′-diphenyl(thio)urea substitution is determined. Furthermore, for the first time, the linear dependence of the non-additivity in the interaction energy on the Hammett substituent constant is reported. The stronger the electron-donating character of the substituent, the larger the three-body non-additive components and the larger their percentage to the total interaction energy.

scholarly journals Hydrogen Bonding Interaction and Structural Change in Some Aliphatic Alcohol-Water Complexes: A Quantum Mechanical MP4 Study

2020 ◽  
Vol 32 (7) ◽  
pp. 1581-1588
Author(s):  
Mrinal J. Bezbaruah ◽  
Benzir Ahmed ◽  
Ibrahim Ali ◽  
Madhab Upadhyaya ◽  
Bipul Bezbaruah
Keyword(s):  
Hydrogen Bonding ◽  
Water Molecule ◽  
Interaction Energy ◽  
Aliphatic Alcohol ◽  
Proton Acceptor ◽  
Quantum Mechanical ◽  
Hydrogen Bonding Interaction ◽  
Fourth Degree ◽  
Bonding Interaction ◽  
Alcohol Water

Hydrogen bonding interaction in low molecular weight alcohols or lower alcohol (viz. methanol and ethanol) with water molecule is quite common. But, due to the presence of bulky groups in higher alcohols (viz. propanol, butanol and pentanol and their isomers) the hydrogen bonding interaction between alcohol and water molecule is significantly different. In alcohol-water heterodimer complexes, water plays an important role in the stability of such system, alcohol will be interacting with water molecule either as proton donor or proton acceptor mode. Quantum mechanical method, fourth degree Møller-Plesset (MP4) perturbation theory is an important tool for computing the interaction energy between the alcohol-water complexes. The interaction energy (IE) and natural bond orbital (NBO) calculations for some common aliphatic alcohol-water complexes (e.g. methanol, ethanol, propanol, butanol and pentanol) and their isomers were computed by using MP4 method.

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