Experimental charge density and topological properties of 3-(tert-butyloxycarbonylamino)bicyclo[1.1.1]pentanecarboxylic acidElectronic supplementary information (ESI) available: multipole population coefficients and a summary of topological descriptors from experiment and theoretical calculations. See http://www.rsc.org/suppdata/p2/b1/b104062f/

2001 ◽  
pp. 1956-1960
Keyword(s):  
Charge Density ◽  
Theoretical Calculations ◽  
Supplementary Information ◽  
Topological Descriptors ◽  
Topological Properties ◽  
Experimental Charge Density

scholarly journals Experimental charge density study and topological properties of Fidarestat

2007 ◽  
Vol 63 (a1) ◽  
pp. s28-s28
Author(s):  
El-E. Bendeif ◽  
C. Jelsch ◽  
B. Guillot ◽  
C. Lecomte ◽  
W. Morgenroth
Keyword(s):  
Charge Density ◽  
Topological Properties ◽  
Density Study ◽  
Experimental Charge Density

Experimental charge density in the transition metal complex Mn2(CO)10: a comparative study

2003 ◽  
Vol 59 (2) ◽  
pp. 234-247 ◽  
Author(s):  
Louis J. Farrugia ◽  
Paul R. Mallinson ◽  
Brian Stewart
Keyword(s):  
Charge Density ◽  
Transition Metal Complex ◽  
Topological Analysis ◽  
Atoms In Molecules ◽  
Topological Properties ◽  
B3lyp Level ◽  
Metal Metal ◽  
Density Study ◽  
Experimental Charge Density ◽  
Metal Ligand

An accurate experimental charge density study at 100 K of Mn2(CO)10 [bis(pentacarbonylmanganese)(Mn—Mn)] has been undertaken. A comparison with previously reported structural determinations reveals no evidence for significant Mn—Mn bond lengthening between 100 and 296 K. The nature of the metal–metal and metal–ligand atom interactions has been studied by topological analysis using the Atoms in Molecules (AIM) approach of Bader [(1990), Atoms in Molecules: a Quantum Theory.Oxford: Clarendon Press]. An analysis of the density ρ(r), the Laplacian of the density ∇2ρ(r b ) and the total energy densities H(r b ) at the bond critical points is used to classify all the chemical bonds as covalent in nature. The results are compared qualitatively and quantitatively with previous charge density studies on this molecule and DFT calculations at the 6-311+G* B3LYP level. The topological properties of the theoretical and experimental densities are in close agreement.

Charge-density analysis of 1-nitroindoline: refinement quality using free R factors and restraints

2011 ◽  
Vol 67 (3) ◽  
pp. 250-262 ◽  
Author(s):  
Bartosz Zarychta ◽  
Jacek Zaleski ◽  
Janusz Kyzioł ◽  
Zdzisław Daszkiewicz ◽  
Christian Jelsch
Keyword(s):  
Charge Density ◽  
Theoretical Calculations ◽  
Local Symmetry ◽  
Anisotropic Model ◽  
Rocket Fuel ◽  
Density Analysis ◽  
R Factors ◽  
Experimental Charge Density ◽  
Significant Attention ◽  
The Ideal

Nitramines and related N-nitro compounds have attracted significant attention owing to their use in rocket fuel and as explosives. The charge density of 1-nitroindoline was determined experimentally and from theoretical calculations. Electron-density refinements were performed using the multipolar atom formalism. In order to design the ideal restraint strategy for the charge-density parameters, R-free analyses were performed involving a series of comprehensive refinements. Different weights were applied to the charge-density restraints, namely the similarity between chemically equivalent atoms and local symmetry. Additionally, isotropic thermal motion and an anisotropic model calculated by rigid-body analysis were tested on H atoms. The restraint weights which resulted in the lowest values of the averaged R-free factors and the anisotropic H-atom model were considered to yield the best charge density and were used in the final refinement. The derived experimental charge density along with intra- and intermolecular interactions was analysed and compared with theoretical calculations, notably with respect to the symmetry of multipole parameters. A comparison of different refinements suggests that the appropriate weighting scheme applied to charge-density restraints can reduce the observed artefacts. The topological bond orders of the molecule were calculated.

Experimental charge density study on FLPs and a FLP reaction product

2018 ◽  
Vol 233 (9-10) ◽  
pp. 723-731
Author(s):  
Christian Joseph Schürmann ◽  
Regine Herbst-Irmer ◽  
Thorsten Lennart Teuteberg ◽  
Daniel Kratzert ◽  
Gerhard Erker ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Density ◽  
Theoretical Calculations ◽  
X Ray Diffraction ◽  
Charge Density Distribution ◽  
X Ray ◽  
Charge Densities ◽  
A Charge ◽  
Density Study ◽  
Experimental Charge Density

Abstract The charge density distribution of the intramolecular frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 (1), the phosphinimine HNPMes2CH2CH2B(C6F5)2 (2), as well as a FLP homologue with nitrogen NEt2CHPhCH2B(C6F5)2 (3) were investigated with Bader’s quantum theory of atoms in molecules (QTAIM). The charge densities were derived from both experimental high-resolution X-ray diffraction data (2, 3) and theoretical calculations (1, 3). The QTAIM analysis for the FLPs 1 and 3 showed the prominent B-pnictogen interaction to be weak dative bonds without significant charge-transfer. This holds also true for the B–N–bond of 2. The nitrogen atom is negatively charged, due to a charge transfer from phosphorous and shows features of a sp2-hybridization. The bond is therefore best described as a non-hypervalent Pδ+–Nδ− moiety.

Protonated nucleobases are not fully ionized and may form stable base pairs in the crystalline state

2017 ◽  
Author(s):  
Prashant Kumar ◽  
Małgorzata Katarzyna Cabaj ◽  
Aleksandra Pazio ◽  
Paulina Maria Dominiak
Keyword(s):  
Charge Transfer ◽  
Charge Density ◽  
Electrostatic Interactions ◽  
Theoretical Calculations ◽  
X Ray Diffraction ◽  
Base Pairs ◽  
Molecular Charge ◽  
Total Interaction ◽  
Cohesive Energies ◽  
Experimental Charge Density

The following paper presents experimental charge density studies of cytosinium chloride, adeninium chloride hemihydrate, and guanine dichloride crystals based on ultra-high resolution X-ray diffraction data and extensive theoretical calculations. Results confirm that the cohesive energies of the studied systems are dominated by contributions from intermolecular electrostatic interactions, as expected for ionic crystals. Electrostatic interactions energies (Ees) usually constitute 95% of total interaction energies. The Ees energies were several times larger in absolute value when compared, for example, to pairs of neutral nucleobases. However, they were not as big as some of the theoretical calculations predicted. This was because the molecules appeared not to be fully ionized in the studied crystals. Apart from chlorine to protonated nucleobase charge transfer, small but visible, charge redistribution within nucleobase cations was observed. Some pairs of single protonated bases in the studied crystals exhibited attractive interactions (negative values of Ees) or unusually low repulsion despite identical molecular charges. This was because strong hydrogen bonding between bases overcompensated overall cation-cation repulsion, the latter being weakened due to charge transfer and molecular charge density polarization.

Protonated nucleobases are not fully ionized and may form stable base pairs in the crystalline state

2017 ◽  
Author(s):  
Prashant Kumar ◽  
Małgorzata Katarzyna Cabaj ◽  
Aleksandra Pazio ◽  
Paulina Maria Dominiak
Keyword(s):  
Charge Transfer ◽  
Charge Density ◽  
Electrostatic Interactions ◽  
Theoretical Calculations ◽  
X Ray Diffraction ◽  
Base Pairs ◽  
Molecular Charge ◽  
Total Interaction ◽  
Cohesive Energies ◽  
Experimental Charge Density

The following paper presents experimental charge density studies of cytosinium chloride, adeninium chloride hemihydrate, and guanine dichloride crystals based on ultra-high resolution X-ray diffraction data and extensive theoretical calculations. Results confirm that the cohesive energies of the studied systems are dominated by contributions from intermolecular electrostatic interactions, as expected for ionic crystals. Electrostatic interactions energies (Ees) usually constitute 95% of total interaction energies. The Ees energies were several times larger in absolute value when compared, for example, to pairs of neutral nucleobases. However, they were not as big as some of the theoretical calculations predicted. This was because the molecules appeared not to be fully ionized in the studied crystals. Apart from chlorine to protonated nucleobase charge transfer, small but visible, charge redistribution within nucleobase cations was observed. Some pairs of single protonated bases in the studied crystals exhibited attractive interactions (negative values of Ees) or unusually low repulsion despite identical molecular charges. This was because strong hydrogen bonding between bases overcompensated overall cation-cation repulsion, the latter being weakened due to charge transfer and molecular charge density polarization.

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