The structure and the hydrogen bonding in the systems formed by the intramolecularly H-bonded systems, namely, maltol (3-hydroxy-2-methyl-4-pyrone), 5, 2,4,6-trinitrophenol, 6, acetylacetone enol, 7, with Lewis bases, phosgene, 8, dioxane, 9, and DMSO, 10, have been studied by density functional theory (B3LYP) and MP2 using the 6-311G* basis set. The continuum solvent effect was simulated by IEF-PCM model. The hydrogen bond analysis using the atoms in molecules (AIM) method was applied by using the MP2(full)/6-311++G** electron density to establish the nature of the bifurcate hydrogen bond (BHB) in these systems as well as contributory factors for its stabilization. The nature of interaction in the intermolecular H-complexes formed by compounds 5- 7 with the Lewis bases 8- 10 was shown to depend on the strength of the intramolecular hydrogen bond O...H and the strength of the base. The critical values of the CO...H and NO...H angles for which the formation of BHB is possible, have been determined.
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Chemistry
January 2025
The University of Western Ontario, Department of Chemistry, 1151 Richmond St. N., N6A 5B7, London, CANADA.
The exploration of phosphorus-nitrogen heterocycles derived from chelating N-donor ligands is an area of research that has lagged behind the development of similar heterocycles based on other main group elements, most notably boron. The fact that phosphorus and nitrogen are both group 15 elements and that their compounds are most commonly viewed as Lewis bases likely contributes to this observation. However, through judicious ligand design and creative use of phosphorus sources that render phosphorus as Lewis acidic and/or electron poor, a variety of heterocyclic architectures are possible.
View Article and Find Full Text PDFDalton Trans
January 2025
Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna, Via P. Gobetti 85, 40129 Bologna, Italy.
In this Frontier Article, the work carried out within our research group in Bologna in the field of surface decorated metal carbonyl clusters will be outlined and put in a more general context. After a short Introduction, clusters composed of a metal carbonyl core decorated on the surface by metal-ligand fragments will be analyzed. Both metal-ligand fragments behaving as Lewis acids and Lewis bases will be considered.
View Article and Find Full Text PDFNat Commun
January 2025
National Key Laboratory of Electronic Films and Integrated Devices, School of Integrated Circuit Science and Engineering, University of Electronic Science and Technology of China, Chengdu, P. R. China.
Suppressing deep-level defects at the perovskite bulk and surface is indispensable for reducing the non-radiative recombination losses and improving efficiency and stability of perovskite solar cells (PSCs). In this study, two Lewis bases based on chalcogen-thiophene (n-Bu4S) and selenophene (n-Bu4Se) having tetra-pyridine as bridge are developed to passivate defects in perovskite film. The uncoordinated Pb and iodine vacancy defects can interact with chalcogen-concave group and pyridine group through the formation of the Lewis acid-base adduct, particularly both the defects can be surrounded by concave molecules, resulting in effective suppression charge recombination.
View Article and Find Full Text PDFMolecules
December 2024
Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Wanstead P.O. Box 64, Barbados.
A computational study of X-H···Y binary hydrogen-bonded complexes was undertaken to examine the red- and blue-shifting behavior of three model X-H proton donors interacting with a series of Lewis bases: Y = NH, NCLi, NCH, NCF, CH, BF, CO, N and Ne. Two of these proton donors, FArH and FCH, have blue-shifting tendencies, while the third, FH, has red-shifting tendencies. A perturbation theory model for frequency shifts that was derived many years ago was employed to partition the predicted frequency shift into the sum of two components, one dependent on the second derivative of the interaction energy with respect to X-H displacement and the other dependent on the X-H bond length change in the binary complex.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Texas A&M University, Department of Chemistry, Texas A&M University, 77842, College Station, UNITED STATES OF AMERICA.
Lewis acids play a central role in a large variety of chemical transformations. The reactivity of the strongest Lewis acids is typically studied in the context of affinity towards hard bases, such as fluoride or oxygenous species. Carbocations can be viewed as soft Lewis acids, possessing significant affinity for softer bases, such as hydride.
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