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Tsirelson, Vladimir G.; Abramov, Y.U.A.; Zavodnik, V. E.; Сташ, А. И.; Белоконева, Е. Л.; Stahn, J.; Pietsch, U.; Feil, D.

doi:10.1023/a:1022474712532

Cited by 46 publications

(57 citation statements)

References 6 publications

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“…Based on the separation between neighboring chloride anions in NH 4 Cl (3.8314(1) ), Cl À ···Cl À bonding interactions also may be expected [40] (Figure 2) similar to those found in NaCl [41] or hydroxylammonium chloride NH 3 OHCl. [42] Therefore, the full set of interionic contacts here should include NÀH···Cl hydrogen bonds, Cl···NÀH pnicogen bonds, and Cl···Cl interactions; the latter cannot be described by the s-hole concept because they form no covalent bonds and thus have no s-holes, but they resemble its "like attracting like" cases.…”

Section: Resultssupporting

confidence: 54%

Experimental Charge Density Evidence for Pnicogen Bonding in a Crystal of Ammonium Chloride

Nelyubina

Korlyukov

2014

ChemPhysChem

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Chemical binding in crystalline ammonium chloride, a simple inorganic salt with an unexpectedly complex bonding pattern, was studied by using a topological analysis of electron density function derived from high-resolution X-ray diffraction. Supported by periodic quantum chemical calculations, it provided experimental evidence for weak σ-hole bonds (1.5 kcal mol(-1) ) that involve ammonium cations in a crystal. Our results show this type of supramolecular interaction to be more numerous than has been found to date by using gas-phase calculations or statistical analysis of CSD.

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Section: Resultssupporting

confidence: 54%

Experimental Charge Density Evidence for Pnicogen Bonding in a Crystal of Ammonium Chloride

Nelyubina

Korlyukov

2014

ChemPhysChem

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“…The quantitative characteristics of these points turn out to be quite close to the experimental ones, especially for the ionic procrystal. The same feature was recently found in other rock-salt-type procrystals (Tsirelson, 1996;Tsirelson et al, 1998). The (3,-1) critical points on interatomic lines in the procrystal were also observed early in the covalent compounds as urea (Stewart, 1991), in L-alanine (Gatti et aL, 1992) and in solid molecular chlorine (Tsirelson, 1994).…”

Section: Topological Analysissupporting

confidence: 77%

X-ray and Electron Diffraction Study of MgO

Tsirelson¹,

Авилов²,

Abramov³

et al. 1998

Acta Crystallogr B Struct Sci

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Precise X-ray and high-energy transmission electron diffraction methods were used for the study of electron density and electrostatic potential in MgO crystals. The structure amplitudes were determined and their accuracy estimated using ab initio Hartree-Fock structure amplitudes as criteria. The electrostatic potential distributions, reconstructed using Fourier series from both X-ray and electron diffraction data, are in satisfactory mutual agreement and are similar to the theory. They, however, suffer from restricted experimental resolution and, therefore, the reconstruction of the electrostatic potential via an analytical structural model is preferable. The x model of electron density was adjusted to X-ray experimental structure amplitudes and those calculated by the HartreeFock method. The electrostatic potential, deformation electron density and the Laplacian of the electron density were calculated with this model. The critical points in both experimental and theoretical model electron densities were found and compared with those for procrystals from spherical atoms and ions. A disagreement 11 concerning the type of critical point at (Z,Z,0) in the area of low, near-uniform electron density is observed. It is noted that topological analysis of the electron density in crystals can be related with a close-packing concept.

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“…Promolecular atomic shell approximation Promolecular models have often been shown as reasonable or even very good approximation levels to model electron density (ED) distributions, for example in chemical bond analysis or molecular similarity applications [47][48][49][50][51][52][53][54][55][56] even if the ED topology may differ between experimental and theoretical models especially at covalent bonds [56]. Analytical descriptions of promolecular ED distributions are either based on atomic or ionic wavefunctions [47-49, 52, 56], exponential functions [51], or fitted Gaussian functions [50,52,55].…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Influence of conformation on the representation of small flexible molecules at low resolution: alignment of endothiapepsin ligands

Leherte

Meurice

Vercauteren

2005

J Comput Aided Mol Des

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In this contribution, we discuss a molecular representation mode for the generation of reduced descriptions of flexible molecules in various conformations. The representations of the endothiapepsin ligands are constituted by graphs of peaks obtained through a hierarchical merging algorithm which combines the location of promolecular electron density (ED) maxima with the decomposition of the molecular structures into fragments. The representations are then aligned through the use of a Monte Carlo/Simulated Annealing procedure. The evaluation function of the alignment solutions is based on the local density values of the peaks and their inter-distances. The applications show that the alignment of a given molecule onto itself, in a different conformation, is successful when a pseudo-topological path length is considered in the evaluation function of the solution, while Cartesian distances are more adapted to the scoring for alignments of two different molecules in their co-crystallized conformation. Results are compared with the available literature data.

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Cited by 46 publications

References 6 publications

Experimental Charge Density Evidence for Pnicogen Bonding in a Crystal of Ammonium Chloride

Experimental Charge Density Evidence for Pnicogen Bonding in a Crystal of Ammonium Chloride

X-ray and Electron Diffraction Study of MgO

Influence of conformation on the representation of small flexible molecules at low resolution: alignment of endothiapepsin ligands

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