Determination of covalent bond orders and atomic valence indices using topological features of the experimental electron density

2007 ◽  
Vol 63 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Vladimir G. Tsirelson ◽  
Ekaterina V. Bartashevich ◽  
Adam I. Stash ◽  
Vladimir A. Potemkin
Keyword(s):  
Electron Density ◽  
Reasonable Agreement ◽  
Covalent Bond ◽  
Bond Orders ◽  
Orbital Theory ◽  
Topological Features ◽  
Experimental Electron Density ◽  
Atomic Valence

We present an approach for the determination of covalent bond orders from the experimental electron density and its derivatives at the bond critical points. An application of this method to a series of organic compounds has shown that it provides a bonding quantification that is in reasonable agreement with that obtained by orbital theory. The `experimental' atomic valence indices are also defined and their significance for the characterization of chemical problems is discussed.

ChemInform Abstract: EXPERIMENTAL ELECTRON DENSITY DETERMINATION OF μ-METHYLENE COMPLEXES OF THE DIMETALLOCYCLOPROPANE TYPE

1982 ◽  
Vol 13 (4) ◽  
Author(s):  
D. A. CLEMENTE ◽  
B. REES ◽  
G. BANDOLI ◽  
M. CINGI BIAGINI ◽  
B. REITER ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Determination ◽  
Experimental Electron Density

DevelopingWinXPRO: a software for determination of the multipole-model-based properties of crystals

2014 ◽  
Vol 47 (6) ◽  
pp. 2086-2089 ◽  
Author(s):  
Adam I. Stash ◽  
Vladimir G. Tsirelson
Keyword(s):  
Computer Program ◽  
Electron Density ◽  
Density Functional ◽  
Atomic Displacement ◽  
Program Package ◽  
The Other ◽  
Output Data ◽  
Crystal Properties ◽  
Experimental Electron Density

The new release of the computer program packageWinXPRO v.3xfor determination of the crystal properties from parameters of the multipole-modeled experimental electron density and anharmonic atomic displacement coefficients is described. The set of properties is significantly extended by using the density functional and information theories. In addition, a built-in multi-functional viewer and programs to display the output data, including the mapping of the chosen functional bonding descriptors onto surfaces of the other properties, are included.

The mapping of electronic energy distributions using experimental electron density

2002 ◽  
Vol 58 (4) ◽  
pp. 632-639 ◽  
Author(s):  
Vladimir G. Tsirelson
Keyword(s):  
Energy Density ◽  
Electron Density ◽  
Electronic Energy ◽  
Kinetic Energy Density ◽  
Energy Distributions ◽  
Structure Factors ◽  
Experimental Electron Density ◽  
Experimental Structure ◽  
Comprehensive Characterization

It is demonstrated that the approximate kinetic energy density calculated using the second-order gradient expansion with parameters of the multipole model fitted to experimental structure factors reproduces the main features of this quantity in a molecular or crystal position space. The use of the local virial theorem provides an appropriate derivation of approximate potential energy density and electronic energy density from the experimental (model) electron density and its derivatives. Consideration of these functions is not restricted by the critical points in the electron density and provides a comprehensive characterization of bonding in molecules and crystals.

scholarly journals Direct air capture of CO2 – topological analysis of the experimental electron density (QTAIM) of the highly insoluble carbonate salt of a 2,6-pyridine-bis(iminoguanidine), (PyBIGH2)(CO3)(H2O)4

IUCrJ ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Christopher G. Gianopoulos ◽  
Zhijie Chua ◽  
Vladimir V. Zhurov ◽  
Charles A. Seipp ◽  
Xiaoping Wang ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Electron Density ◽  
Topological Analysis ◽  
Neutron Data ◽  
X Ray ◽  
Topological Features ◽  
Direct Air Capture ◽  
Air Capture ◽  
Experimental Electron Density ◽  
Carbonate Salt

Chemical bonding and all intermolecular interactions in the highly insoluble carbonate salt of a 2,6-pyridine-bis(iminoguanidine), (PyBIGH2)(CO3)(H2O)4, recently employed in the direct air capture of CO2 via crystallization, have been analyzed within the framework of the quantum theory of atoms in molecules (QTAIM) based on the experimental electron density derived from X-ray diffraction data obtained at 20 K. Accurate hydrogen positions were included based on an analogous neutron diffraction study at 100 K. Topological features of the covalent bonds demonstrate the presence of multiple bonds of various orders within the PyBIGH2 2+ cation. Strong hydrogen bonds define ribbons comprising carbonate anions and water molecules. These ribbons are linked to stacks of essentially planar dications via hydrogen bonds from the guanidinium moieties and an additional one to the pyridine nitrogen. The linking hydrogen bonds are approximately perpendicular to the anion–water ribbons. The observation of these putative interactions provided motivation to characterize them by topological analysis of the total electron density. Thus, all hydrogen bonds have been characterized by the properties of their (3,−1) bond critical points. Weaker interactions between the PyBIGH2 2+ cations have similarly been characterized. Integrated atomic charges are also reported. A small amount of cocrystallized hydroxide ion (∼2%) was also detected in both the X-ray and neutron data, and included in the multipole model for the electron-density refinement. The small amount of additional H+ required for charge balance was not detected in either the X-ray or the neutron data. The results are discussed in the context of the unusually low aqueous solubility of (PyBIGH2)(CO3)(H2O)4 and its ability to sequester atmospheric CO2.

Characterization of the nucleation precursor (H2SO4–(CH3)2NH) complex: intra-cluster interactions and atmospheric relevance

RSC Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 5824-5836 ◽  
Author(s):  
Yan Ma ◽  
Jiao Chen ◽  
Shuai Jiang ◽  
Yi-Rong Liu ◽  
Teng Huang ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Electron Density ◽  
Nucleation Process ◽  
Density Analysis ◽  
Electron Density Analysis

Amines have been proposed to participate in the nucleation process, but the electron density analysis and the determination of a temperature dependence of the clusters are still lacking.

Charge density in crystalline citrinin from X-ray diffraction at 19 K

1996 ◽  
Vol 74 (6) ◽  
pp. 1145-1161 ◽  
Author(s):  
Pietro Roversi ◽  
Felicita Merati ◽  
Riccardo Destro ◽  
Mario Barzaghi
Keyword(s):  
Electron Density ◽  
Chemical Reactivity ◽  
Topological Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Path ◽  
Topological Features ◽  
Path Lengths ◽  
The Stability ◽  
Experimental Electron Density

For the fungal metabolite citrinin, C13H14O5, the total experimental electron distribution ρ(r) and its Laplacian [Formula: see text] have been obtained from an extensive set (36 564 measurements) of single-crystal X-ray diffracted intensities at a temperature of 19 ± 2 K. Relevant steps in data collection and processing are reported. The resulting 7698 independent intensity data have been analysed with a multipole (pseudoatoms) formalism. The topological properties of ρ(r) have been determined according to the quantum theory of atoms in molecules. CC and CO bond path lengths have been obtained by numerical integration; their values are found to be well correlated with those of the electron density at the bond critical points. Topological features have been used to characterize the extension of the conjugated system of the molecule, and to confirm the stability of its rings, particularly the two formed by intramolecular H bonds. Maps of [Formula: see text] are presented, showing details in the valence charge distribution and providing a very sensitive tool for analysing dependence of the density on the model adopted to interpret X-ray data. The known chemical reactivity of the molecule towards nucleophiles at a Csp2 atom is confirmed by the shape of the molecular reactive surface (the zero envelope of [Formula: see text]). Key words: experimental electron density, low-temperature X-ray diffraction, topological analysis, Laplacian of ρ.

scholarly journals Experimental and theoretical characterization of the Zn—Zn bond in [Zn2(η5-C5Me5)2]

2007 ◽  
Vol 63 (6) ◽  
pp. 862-868 ◽  
Author(s):  
Juan F. Van der Maelen ◽  
Enrique Gutiérrez-Puebla ◽  
Ángeles Monge ◽  
Santiago García-Granda ◽  
Irene Resa ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Functional ◽  
Topological Analysis ◽  
Open Shell ◽  
Synchrotron Diffraction ◽  
Functional Theory ◽  
Metal Metal ◽  
Moller Plesset ◽  
Experimental Electron Density

The existence and characterization of a bond between the Zn atoms in the recently synthesized complex [Zn2(η5-C5Me5)2], as well as between Zn and ligand C atoms is firmly based on neutron diffraction and low-temperature X-ray synchrotron diffraction experiments. The multipolar analysis of the experimental electron density and its topological analysis by means of the `Atoms in Molecules' (AIM) approach reveals details of the Zn—Zn bond, such as its open-shell intermediate character (the results are consistent with a typical metal–metal single bond), as well as many other topological properties of the compound. Experimental results are also compared with theoretical ab initio calculations of the DFT (density functional theory) and MP2 (Møller-Plesset perturbation theory) electron densities, giving a coherent view of the bonding in the complex. For instance, charges calculated from the AIM approach applied to the atomic basin of each Zn atom are, on average, +0.72 e from both the experimental and the theoretical electron density, showing a moderate charge transfer from the metal, confirmed by the calculated topological indexes.

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