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Właściwości kwasu salicylowego i jego wybranych pochodnych w świetle metod modelowania molekularnego

Kaczmarek Anna, Kizior Beata, Zierkiewicz Wiktor, Jezierska Aneta

Chemik

2023

Nr 1-4

66--70

Salicylany są stosowane od wieków jako leki na różne dolegliwości. Wiele związków z tej grupy powstało w wyniku modyfikacji kwasu salicylowego, np. kwasu acetylosalicylowego (popularnego leku aspiryny) czy salicylanu fenylu (Salolu). Interesującym związkiem jest również kwas salicylurowy, będący głównym metabolitem salicylanów. Dla wspomnianych cząsteczek wykonano symulacje kwantowo-chemiczne w oparciu o Teorię Funkcjonału Gęstości (DFT) w fazie gazowej, a także w obecności rozpuszczalnika. Wpływ wewnątrzcząsteczkowego wiązania wodorowego, obecnego w kwasie salicylowym i salicylanie fenylu, na właściwości cząsteczek został również uwzględniony w badaniach. Analizę topologiczną i struktury elektronowej badanych cząsteczek wykonano według Kwantowej Teorii Atomów w Cząsteczkach (QTAIM) oraz Indeksu Oddziaływań Niekowalencyjnych (NCI).

Salicylates have been used for centuries as medicine for various ailments. Many compounds of this group were obtained as a result of modification of salicylic acid, such as acetylsalicylic acid (a popular aspirin drug) and phenyl salicylate (Salol). Salicyluric acid, which is the main metabolite of salicylates, is also an interesting compound. Quantum-chemical simulations based on Density Functional Theory (DFT) in the gas phase, as well as in the presence of a continuum solvation model, were performed for the mentioned molecules. The effect of intramolecular hydrogen bonding, present in salicylic acid and phenyl salicylate, on the properties of the molecules was taken into account in the study. Topological and electron structure analyses of the molecules were carried out according to the Quantum Theory of Atoms in Molecules (QTAIM) and the Non-Covalent Interactions (NCI) index.

Zastosowanie topologicznej analizy gęstości elektronowej do opisu oddziaływań niekowalencyjnych

Bankiewicz B., Rybarczyk-Pirek A., Małecka M., Domagała M., Palusiak M.

Wiadomości Chemiczne

2014

[Z] 68, 5-6

457--486

All atomic and molecular properties are governed by an electron density distribution. Thus, the methods that deal with an analysis of the electron density distribution should have a particular appeal for chemists and help to understand the electron structure of molecules. The Quantum Theory of Atoms in Molecules gives the unique opportunity to have an insight into a region (e.g., an atom) of a given system (e.g. a molecule), delivering partitioning scheme which is defined explicitly within the rigorous quantum theory, from one side, and is applicable for experimentally available set of observables, from the other side. In that way QTAIM delivers a chemist a theoretical tool to study a small part of a molecule only, instead of dealing with the total energy of a whole system. In consequence, QTAIM has become one of the most powerful utilities of modern chemistry, forming a bridge between advanced theoretical and experimental techniques. In particular the properties of the electron density function in the so-called bond critical point (BCP, the (3, -1) saddle point on electron density curvature) seem to be valuable information for chemists, since it was proven in many papers that the chemical bonding can be characterized and classified on the basis of electron density characteristics measured in BCPs . In this review we firstly give a brief introduction to the theory, explaining most basic terms and dependences. In the main part of the review we discuss application of QTAIM in the qualitative and quantitative analysis of several various noncovalent interactions, focusing readers attention on such aspects as classification of interactions and interaction energy assessment. Both theoretical and experimental approaches are taken into account. We also discuss extensions of QTAIM to the analysis of the so called source function – the method which additionally enlarge interpretative possibilities of its parent theory. Finally, we give some examples which perhaps escape a rigorous QTAIM definition of chemical bonding. We acquaint the potential reader with arguments being pro- and against the QTAIM-based deterministic model of a chemical bond.