Towards the use of experimental electron densities to estimate reliable lattice energies

CrystEngComm ◽  
2018 ◽  
Vol 20 (36) ◽  
pp. 5340-5347 ◽  
Author(s):  
Mark A. Spackman
Keyword(s):  
Electron Densities ◽  
Charge Densities ◽  
Lattice Energies

Lattice energies derived from experimental charge densities are critically assessed, with a view to encouraging further research of this nature.

scholarly journals Frozen-density embedding theory with average solvent charge densities from explicit atomistic simulations

2016 ◽  
Vol 18 (31) ◽  
pp. 21069-21078 ◽  
Author(s):  
Andrey Laktionov ◽  
Emilie Chemineau-Chalaye ◽  
Tomasz A. Wesolowski
Keyword(s):  
Atomistic Simulations ◽  
Electron Densities ◽  
Charge Densities ◽  
Embedding Theory ◽  
Molecular Electron ◽  
Oppenheimer Approximation

Besides molecular electron densities obtained within the Born–Oppenheimer approximation (ρB(r)) to represent the environment, the ensemble averaged density (〈ρB〉(r)) is also admissible in frozen-density embedding theory (FDET) [Wesolowski, Phys. Rev. A, 2008, 77, 11444].

X-Ray Charge Densities and Chemical Bonding

1997 ◽  
Author(s):  
Philip Coppens
Keyword(s):  
Chemical Bonding ◽  
Electron Density Distribution ◽  
Comprehensive Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Charge Densities ◽  
Fundamental Information ◽  
Thermodynamic Measurements ◽  
Lattice Energies ◽  
Theoretical Results

This book deals with the electron density distribution in molecules and solids as obtained experimentally by X-ray diffraction. It is a comprehensive treatment of the methods involved, and the interpretation of the experimental results in terms of chemical bonding and intermolecular interactions. Inorganic and organic solids, as well as metals, are covered in the chapters dealing with specific systems. As a whole, this monograph is especially appealing because of its broad interface with numerous disciplines. Accurate X-ray diffraction intensities contain fundamental information on the charge distribution in crystals, which can be compared directly with theoretical results, and used to derive other physical properties, such as electrostatic moments, the electrostatic potential and lattice energies, which are accessible by spectroscopic and thermodynamic measurements. Consequently, the work will be of great interest to a broad range of crystallographers and physical scientists.

scholarly journals Intermolecular Interactions in Ionic Crystals of Nucleobase Chlorides—Combining Topological Analysis of Electron Densities with Energies of Electrostatic Interactions

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 668 ◽  
Author(s):  
Prashant Kumar ◽  
Małgorzata Katarzyna Cabaj ◽  
Paulina Maria Dominiak
Keyword(s):  
Intermolecular Interactions ◽  
Critical Points ◽  
Electrostatic Interactions ◽  
Point Of View ◽  
Ionic Crystals ◽  
Interaction Energies ◽  
Electron Densities ◽  
Charge Densities ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Understanding intermolecular interactions in crystals of molecular ions continues to be difficult. On the one hand, the analysis of interactions from the point of view of formal charges of molecules, similarly as it is commonly done for inorganic ionic crystals, should be performed. On the other hand, when various functional groups are present in the crystal, it becomes natural to look at the interactions from the point of view of hydrogen bonding, π…π stacking and many other kinds of non-covalent atom–atom bonding. Often, these two approaches seem to lead to conflicting conclusions. On the basis of experimental charge densities of cytosinium chloride, adeninium chloride hemihydrate, and guanine dichloride crystals, with the help of theoretical simulations, we have deeply analysed intermolecular interactions among protonated nucleobases, chloride anions and water molecules. Here, in the second paper of the series of the two (Kumar et al., 2018, IUCrJ 5, 449–469), we focus on applying the above two approaches to the large set of dimers identified in analysed crystals. To understand electrostatic interactions, we analysed electrostatic interaction energies (Ees) computed directly from molecular charge densities and contrasted them with energies computed only from net molecular charges, or from a sum of electric multipolar moments, to find the charge penetration contribution to Ees. To characterize non-covalent interactions we performed topological analyses of crystal electron densities and estimated their interaction energies (EEML) from properties of intermolecular bond critical points. We show that the overall crystal architecture of the studied compounds is governed by the tight packing principle and strong electrostatic attractions and repulsions between ions. Many ions are oriented to each other in a way to strengthen attractive electrostatic interactions or weaken strong repulsion, but not all of them. Numerous bond critical points and bond paths were found between ions, including nucleobase cations despite their overall repulsive interactions. It is clear there is no correlation between EEML and Ees. However, strong relation between EEML and the charge penetration component of Ees is observed. The relation holds regardless of interaction types or whether or not interacting molecules bear the same or opposite charges. Thus, a charge density-based approach for computing intermolecular interaction energies and the atom–atom approach to analyse non-covalent interactions do complement each other, even in ionic systems.

Pyridopyridazines. II. Some reactions of Pyrido[2,3-d]- and Pyrido[3,4-d]-pyridazine

1969 ◽  
Vol 22 (8) ◽  
pp. 1745 ◽  
Author(s):  
DB Paul ◽  
HJ Rodda
Keyword(s):  
Electron Densities ◽  
Charge Densities ◽  
Bond Lengths ◽  
Alkaline Conditions ◽  
Chlorous Acid

Pyridopyridazines have been oxidized under acid and alkaline conditions and the sites of oxidation have been rationalized on the basis of charge densities. Pyrido-[2,3-d]pyridazine has been brominated, aminated, and made to react with hypo-chlorous acid and with peracids. The positions of substitution and addition are discussed in relation to calculated π-electron densities and bond lengths. Attention is drawn to some unusual features of the N.M.R. spectra of 1,2-diazine N-oxides.

On the reliability of volume-based thermodynamics for inorganic-organic salts and coordination compounds with uncharged ligands

2017 ◽  
Author(s):  
Robson de Farias
Keyword(s):  
Coordination Compound ◽  
Coordination Compounds ◽  
Formation Enthalpy ◽  
Lattice Energy ◽  
Chemical Hardness ◽  
Acid Anion ◽  
Organic Salts ◽  
Density Values ◽  
Lattice Energies

In the present work, the reliability of the volume-based thermodynamics (VBT) methods in the calculation of lattice energies is investigated by applying the “traditional” Kapustinskii equation [8], as well as Glasser-Jenkins [3] and Kaya [5] equations to calculate the lattice energies for Na, K and Rb pyruvates [9-11] as well as for the coordination compound [Bi(C<sub>7</sub>H<sub>5</sub>O<sub>3</sub>)<sub>3</sub>C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>] [17] (in which C<sub>12</sub>H<sub>8</sub>N<sub>2</sub> = 1,10 phenathroline and C<sub>7</sub>H<sub>5</sub>O<sub>3</sub><sup>-</sup>= <i>o</i>-hyddroxybenzoic acid anion). As comparison, the lattice energies are also calculated using formation enthalpy values for sodium pyrivate and [Bi(C<sub>7</sub>H<sub>5</sub>O<sub>3</sub>)<sub>3</sub>C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>]. For the pyruvates, is verified that none of the considered approach, Kapustinskii, Glasser, Kaya or density, provides values that agrees in an acceptable % difference, with the lattice energy values calculated from the formation enthalpy values. However, it must be pointed out that Kaya approach, with deals with a chemical hardness approach is the better one for such kind of inorganic-organic salts. Based on data obtained for [Bi(C<sub>7</sub>H<sub>5</sub>O<sub>3</sub>)<sub>3</sub>C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>] is concluded that the only one VBT method that provides reliable lattice energies for compounds with bulky uncharged ligands is that one based on density values (derived by Glasser-Jenkins).

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