The suitability and accuracy of the Huynh electronic parameter (HEP) was further tested to reveal remote substituent effects in pyridines, which are located five or six bonds away from the reporter probe. These values show an excellent correlation to Hammett σ-constants of the respective substituents with coefficients of R =0.9856 (σ ) and R =0.9857 (σ ). Based on this observation, a methodology for the re-evaluation of certain Hammett constants with larger uncertainties has been proposed and demonstrated. Moreover, the scope of HEP was extended to various neutral pnictogen and chalcogen donors during which "transphobia effects" were revealed for mixed NHC complexes containing phosphites, arsine and stibine for the first time.
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http://dx.doi.org/10.1002/chem.201902795 | DOI Listing |
J Phys Chem A
December 2024
Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, Wrocław 50-370, Poland.
J Phys Chem A
December 2024
College of Chemistry and Materials Science, Hebei Key Laboratory of Inorganic Nano-Materials, Hebei Normal University, Shijiazhuang 050024, China.
Halogen, chalcogen, pnictogen, and tetrel bonds in organocatalysis have gained noticeable attention. In this work, carbon-bromide bond activation in the Ritter reaction by bidentate imidazole-type halogen, chalcogen, pnicogen, and tetrel bond donors was studied by density functional theory. All of the above four kinds of catalysts exhibited excellent catalytic performance.
View Article and Find Full Text PDFChem Rec
December 2024
Department of Chemistry, Universidade Federal de Minas Gerais (UFMG), 31.270-901, Belo Horizonte, MG, Brazil.
Alkylation reactions and their products are considered crucial in various contexts. Synthetically, the alkylation of a nucleophile is usually promoted using hazardous alkyl halides. Here, we aim to highlight the potential of pnictogen (ammonium or phosphonium) and chalcogen salts (sulfonium, selenonium, and telluronium) to function as alkylating agents.
View Article and Find Full Text PDFChem Sci
September 2024
Université libre de Bruxelles (ULB), Engineering of Molecular NanoSystems Avenue F. Roosevelt 50, CP165/64 1050 Brussels Belgium
J Am Chem Soc
September 2024
Department of Chemistry and Pharmaceutical Sciences, AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
Herein, we dismiss a recent proposal by Civiš, Hobza, and co-workers to modify the IUPAC definition of hydrogen bonds in order to expand the scope from protonic Y-H to hydridic Y-H hydrogen-bond donor fragments [ , , 8550]. Based on accurate Kohn-Sham molecular orbital (KS-MO) analyses, we falsify the conclusion that interactions involving protonic and hydridic hydrogens are both hydrogen bonds; they are not. Instead, our quantitative KS-MO, energy decomposition, and Voronoi deformation density analyses reveal two fundamentally different bonding mechanisms for protonic Y-H and hydridic Y-H fragments which go with charge transfer in opposite directions.
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