Chemical Information from Charge Density Studies

Flierler, Ulrike; Farrugia, Louis J.

doi:10.1007/978-90-481-3836-4_12

Cited by 3 publications

(3 citation statements)

References 114 publications

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“…Ac ommon trait of many M&ES is that the sole knowledge of their crystal structure is not enough to infer their chemical and electronics tructure. [195,224,225] Chemists like to draw dashes, arrows and dotted lines connecting atoms or groups of them, but there are plenty of M&ES where this operation is ambiguous or simplyi mpossible, if based on their structure alone. Electron density and wavefunction analyses are often used to provide insights.…”

Section: Spin Densitiesmentioning

confidence: 99%

Quantum Crystallography: Current Developments and Future Perspectives

Genoni

Bučinský

Claiser

et al. 2018

Chemistry A European J

124

114

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Crystallography and quantum mechanics have always been tightly connected because reliable quantum mechanical models are needed to determine crystal structures. Due to this natural synergy, nowadays accurate distributions of electrons in space can be obtained from diffraction and scattering experiments. In the original definition of quantum crystallography (QCr) given by Massa, Karle and Huang, direct extraction of wavefunctions or density matrices from measured intensities of reflections or, conversely, ad hoc quantum mechanical calculations to enhance the accuracy of the crystallographic refinement are implicated. Nevertheless, many other active and emerging research areas involving quantum mechanics and scattering experiments are not covered by the original definition although they enable to observe and explain quantum phenomena as accurately and successfully as the original strategies. Therefore, we give an overview over current research that is related to a broader notion of QCr, and discuss options how QCr can evolve to become a complete and independent domain of natural sciences. The goal of this paper is to initiate discussions around QCr, but not to find a final definition of the field.

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Section: Spin Densitiesmentioning

confidence: 99%

Quantum Crystallography: Current Developments and Future Perspectives

Genoni

Bučinský

Claiser

et al. 2018

Chemistry A European J

124

114

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“…The experimental charge density analysis, based on lowtemperature high-resolution X-ray diffraction, is a reliable tool for the study of both inter-and intra-molecular interactions in crystalline solid state materials (Koritsanszky et al, 1998;Koritsanszky & Coppens, 2001;Jelsch et al, 1998;Lecomte et al, 2004;Fournier et al, 2009;Stalke & Ott, 2008). To predict the nature of chemical bonding in any molecule, to precisely evaluate the interactions between drug and receptor sites and understand molecular recognition at electronic level, charge density analysis provides the ultimate solution (Housset et al, 2000;Muzet et al, 2003;Li et al, 2002;Grabowsky et al, 2009;Destro et al, 2005;Flaig et al, 2001;Guillot et al, 2001;Stalke, 2011;Flierler et al, 2011). The knowledge of charge density distribution is valuable for drug designing through crystal engineering approaches (Duggirala et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Crystal engineering of co-crystal of nicotinic acid and pyrogallol: an experimental and theoretical electron density analysis

Iqbal¹,

Mehmood²,

Noureen³

et al. 2021

Acta Crystallogr Sect B

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Experimental electron density analysis by means of high-resolution X-ray diffraction data up to sinθ/λmax = 1.11 Å−1 at 100 (1) K has been performed to analyze the detailed structure and the strength of intermolecular interactions responsible for the formation of a new solid form of nicotinic acid (NA), cocrystallized with pyrogallol (PY). There are two NA–PY units in the asymmetric unit. The experimental results are compared with the results obtained from theoretical structure factors modeled using periodic boundary DFT calculations. Both refinements were carried out using the Hansen and Coppens multipolar formalism (in MoPro program). The non-centrosymmetric and polar nature of the crystal system rendered the multipolar refinement challenging which was addressed by involving the transferability principle. This study highlights the significance of the transferability principle in electron density modeling in non-routine situations. The 2:2 cocrystal of NA–PY exhibits a zigzag, brickwall and sheet-like layered structure in three dimensions and is stabilized by strong intra- and inter-molecular hydrogen bonding through N—H...O and O—H...O bonds, some of them due to the zwitterion nature of NA as well as weak interactions between the PY molecules. Ranking these interactions via topological analysis of the electron density shows the leading role of the NA–NA substructure which drives the organization of the cocrystals. These strong interactions between the NA zwitterions may explain why Z′ = 2.

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“…The intuitive-heuristic instruments that are currently employed to judge on reactivity (crystal field splitting, nucleo- or electrophilicity, donor strength, conjugation, delocalization, partial charges, etc.) can eventually be transferred to hard quantities and provide the base for rational design of crucial building blocks even for organolithiums. , The topological analysis based on the Quantum Theory of Atoms in Molecules (QTAIM) provides physically meaningful numbers, for example, on the molecular graph based on bond paths (BPs), density at the bond critical points ρ( r BCP ), and the Laplacians, hence the second derivative of the density at the bond critical point ∇ 2 ρ( r BCP ) or the ellipticity of the bond (ε). − The values of the charge density, ρ( r BCP ), and the Laplacian ∇ 2 ρ( r BCP ), at the BCPs can be used to distinguish between various types of interactions. The position of the BCP corresponds to the polarization of the bond.…”

Section: Introductionmentioning

confidence: 99%

Insight into the Bonding and Aggregation of Alkyllithiums by Experimental Charge Density Studies and Energy Decomposition Analyses

et al. 2020

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In this Article, the organolithiums [((−)-sparteine)-Li t Bu] (1), [(ABCO)Li t Bu] 2 (2), and [(ABCO) 2 (Li i Pr) 4 ] (3) are investigated by means of experimental and theoretical charge density determination to elucidate the nature of the Li−C and Li− N bonds. Furthermore, the valence shell charge concentrations (VSCCs) in the nonbonding region of the deprotonated C α -atom will provide some insight on the localization of the carbanionic lone pair. Analysis of the electron density (ρ(r BCP )), Laplacian (∇ 2 ρ(r BCP )), and the energy decomposition (EDA) confirmed that the Li−C/N bond exhibits astonishingly similar characteristics, to reveal an increasingly polar contact with decreasing aggregate size. This explains former observations on the incorporation of halide salts in organolithium reagents. Furthermore, it could be shown that the bonding properties of the i Pr group are similar to those of the t Bu substituent. The accuracy of fit to all previously determined properties in organolithiums is remarkable.

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Chemical Information from Charge Density Studies

Cited by 3 publications

References 114 publications

Quantum Crystallography: Current Developments and Future Perspectives

Quantum Crystallography: Current Developments and Future Perspectives

Crystal engineering of co-crystal of nicotinic acid and pyrogallol: an experimental and theoretical electron density analysis

Insight into the Bonding and Aggregation of Alkyllithiums by Experimental Charge Density Studies and Energy Decomposition Analyses

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