Journal ArticleDOI
From weak to strong interactions: A comprehensive analysis of the topological and energetic properties of the electron density distribution involving X–H⋯F–Y systems
TLDR
In this paper, the topological and energetic properties of the electron density distribution ρ(r) of isolated pairwise H⋯F interaction have been theoretically calculated at several geometries and represented against the corresponding internuclear distances.Abstract:
The topological and energetic properties of the electron density distribution ρ(r) of the isolated pairwise H⋯F interaction have been theoretically calculated at several geometries (0.8<d<2.5 A) and represented against the corresponding internuclear distances. From long to short geometries, the results presented here lead to three characteristic regions, which correspond to three different interaction states. While the extreme regions are associated to pure closed-shell (CS) and shared-shell (SS) interactions, the middle one has been related to the redistribution of ρ(r) between those electronic states. The analysis carried out with this system has permitted to associate the transit region between pure CS and SS interactions to internuclear geometries involved in the building of the H–F bonding molecular orbital. A comparative analysis between the formation of this orbital and the behavior of some characteristic ρ(r) properties has indicated their intrinsic correspondence, leading to the definition of a bond degree parameter [BD=HCP/ρCP; HCP and ρCP being the total electron energy density and the electron density value at the H⋯F (3,−1) critical point]. Along with the isolated pairwise H⋯F interaction, 79 X–H⋯F–Y (neutral, positively and negatively charged) complexes have been also theoretically considered and analyzed in terms of relevant topological and energetic properties of ρ(r) found at their H⋯F critical points. In particular, the interaction energies of X–H⋯F–Y pure CS interactions have been estimated by using the bond degree parameter. On the other hand, the [F⋯H⋯F]− proton transfer geometry has been related to the local maximum of the electron kinetic energy density (GCP)max.read more
Citations
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Covalent Organic Framework (C6N6) as a Drug Delivery Platform for Fluorouracil to Treat Cancerous Cells: A DFT Study
TL;DR: The covalent triazine framework C6N6 possesses the therapeutic potential to act as a nanocarrier for FU to treat cancer and will also provide motivation to the scientific community to explore new surfaces for drug delivery applications.
Journal ArticleDOI
Theoretical insight into the interaction between SnX2 (X = H, F, Cl, Br, I) and benzene
TL;DR: The results presented in this work shed some light on the nature of the interactions associated with crystalline structural motifs involving low-valent tin complexed with neutral aryl rings using the symmetry-adapted perturbation theory (SAPT).
Journal ArticleDOI
The strong OHO hydrogen bond. How much covalency
TL;DR: In this paper, the AIM parameters of the strong NHO hydrogen bond were compared with those of the weak NHO bond in this complex at different temperatures and the values of the electron density, its Laplacian, and the energy densities at both the critical points between the proton and the oxygen atoms in the OHO hydrogen link were correlated with the OH and HO distances.
Journal ArticleDOI
Improving phase-transfer catalysis by enhancing non-covalent interactions
TL;DR: Intermolecular interactions between a well-known alkaloid quinine-derived phase transfer catalyst and four different anions were characterised, analysing the competition between the pure ion-pair interaction and the intermolescular hydrogen bond established upon complexation.
Journal ArticleDOI
Use of Quantum Theory of Atoms in Molecules in the Search for Appropriate Hydrogen Atom Locations in X-ray Diffraction Based Studies
TL;DR: In this article, a novel approach for the determination of hydrogen positions in studies based on X-ray diffraction is presented, where the comparison of proton positions with their corresponding electron density maxima has been performed by means of the Quantum Theory of Atoms in Molecules.
References
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General atomic and molecular electronic structure system
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Note on an Approximation Treatment for Many-Electron Systems
Chr. Møller,Milton S. Plesset +1 more
TL;DR: In this article, a perturbation theory for treating a system of n electrons in which the Hartree-Fock solution appears as the zero-order approximation was developed, and it was shown by this development that the first order correction for the energy and the charge density of the system is zero.
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TL;DR: In this article, the quantum atom and the topology of the charge desnity of a quantum atom are discussed, as well as the mechanics of an atom in a molecule.
Journal ArticleDOI
Self‐consistent molecular orbital methods 25. Supplementary functions for Gaussian basis sets
TL;DR: In this paper, a modified basis set of supplementary diffuse s and p functions, multiple polarization functions (double and triple sets of d functions), and higher angular momentum polarization functions were defined for use with the 6.31G and 6.311G basis sets.