Quantum-Chemical and Force-Field Investigations of Ice Ih:  Computation of Proton-Ordered Structures and Prediction of Their Lattice Energies

2004 ◽  
Vol 108 (40) ◽  
pp. 15856-15864 ◽  
Author(s):  
Tomas K. Hirsch ◽  
Lars Ojamäe
Keyword(s):  
Force Field ◽  
Quantum Chemical ◽  
Ordered Structures ◽  
Field Investigations ◽  
Lattice Energies

New solvates and a salt of the anti-HIV compound etravirine

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Marieta Muresan-Pop ◽  
Sergiu Macavei ◽  
Alexandru Turza ◽  
Gheorghe Borodi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectroscopy ◽  
Force Field ◽  
Single Crystal ◽  
Total Energy ◽  
Hirshfeld Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Energies ◽  
Anti Hiv

Four new solvates of the anti-HIV compound etravirine [systematic name: 4-({6-amino-5-bromo-2-[(4-cyanophenyl)amino]pyrimidin-4-yl}oxy)-3,5-dimethylbenzonitrile, C20H15BrN6O] with dimethyl sulfoxide (C2H6OS, two distinct monosolvates), 1,4-dioxane (C4H8O2, the 0.75-solvate) and N,N-dimethylacetamide (C4H9NO, the monosolvate), which exhibit conversion to the same anhydrous etravirine phase upon desolvation, and a stable etravirinium oxalate salt {6-amino-5-bromo-4-(4-cyano-2,6-dimethylphenoxy)-2-[(4-cyanophenyl)amino]pyrimidin-1-ium hemioxalate, C20H16BrN6O+·0.5C2O4 2−} were obtained. The crystal structures were solved by single-crystal X-ray diffraction and analyzed by powder X-ray diffraction, and the intermolecular interactions were explored by Hirshfeld surface analysis. Lattice energies were evaluated using the atom–atom force field Coulomb–London–Pauli (AA CLP) approximation, which distributes the total energy as four separate contributions: Coulombic, polarization, dispersion and repulsion. The formation of the solvates and the oxalate salt was further characterized by thermal analysis and IR spectroscopy.

Vibrational spectra of 1,1,3,3-tetramethyl-2-nitroguanidine and their interpretation with the use of scaling of quantum-chemical force field

2008 ◽  
Vol 57 (3) ◽  
pp. 499-505 ◽  
Author(s):  
L. S. Khaikin ◽  
O. E. Grikina ◽  
B. V. Lokshin ◽  
K. P. Dyugaev ◽  
A. M. Astakhov
Keyword(s):  
Force Field ◽  
Vibrational Spectra ◽  
Quantum Chemical ◽  
Chemical Force

A general intermolecular force field based on tight-binding quantum chemical calculations

2017 ◽  
Vol 147 (16) ◽  
pp. 161708 ◽  
Author(s):  
Stefan Grimme ◽  
Christoph Bannwarth ◽  
Eike Caldeweyher ◽  
Jana Pisarek ◽  
Andreas Hansen
Keyword(s):  
Force Field ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Tight Binding ◽  
Intermolecular Force

scholarly journals Evaluation of Docking Target Functions by the Comprehensive Investigation of Protein-Ligand Energy Minima

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Igor V. Oferkin ◽  
Ekaterina V. Katkova ◽  
Alexey V. Sulimov ◽  
Danil C. Kutov ◽  
Sergey I. Sobolev ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Force Field ◽  
Quantum Chemical ◽  
Target Function ◽  
Binding Energies ◽  
Low Energy ◽  
Implicit Solvent ◽  
Energy Calculation ◽  
Solvent Models ◽  
Docking Program

The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.

scholarly journals An optimized intermolecular force field for hydrogen-bonded organic molecular crystals using atomic multipole electrostatics

2016 ◽  
Vol 72 (4) ◽  
pp. 477-487 ◽  
Author(s):  
Edward O. Pyzer-Knapp ◽  
Hugh P. G. Thompson ◽  
Graeme M. Day
Keyword(s):  
Force Field ◽  
Crystal Structures ◽  
Force Fields ◽  
Molecular Crystals ◽  
Intermolecular Force ◽  
Organic Molecular Crystals ◽  
Organic Solid ◽  
Lattice Energies ◽  
Validation Set ◽  
Unit Cell Dimensions

We present a re-parameterization of a popular intermolecular force field for describing intermolecular interactions in the organic solid state. Specifically we optimize the performance of the exp-6 force field when used in conjunction with atomic multipole electrostatics. We also parameterize force fields that are optimized for use with multipoles derived from polarized molecular electron densities, to account for induction effects in molecular crystals. Parameterization is performed against a set of 186 experimentally determined, low-temperature crystal structures and 53 measured sublimation enthalpies of hydrogen-bonding organic molecules. The resulting force fields are tested on a validation set of 129 crystal structures and show improved reproduction of the structures and lattice energies of a range of organic molecular crystals compared with the original force field with atomic partial charge electrostatics. Unit-cell dimensions of the validation set are typically reproduced to within 3% with the re-parameterized force fields. Lattice energies, which were all included during parameterization, are systematically underestimated when compared with measured sublimation enthalpies, with mean absolute errors of between 7.4 and 9.0%.

Tautomerism and stereochemistry of dihydroxyperylenequinones: Force field investigations

1993 ◽  
Vol 124 (4) ◽  
pp. 431-439 ◽  
Author(s):  
Ch. Etzlstorfer ◽  
H. Falk ◽  
N. Müller
Keyword(s):  
Force Field ◽  
Field Investigations
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