The nucleophilic character and stability of the carbanions vs. alkoxides derived from 2,2,2-trifluoro-1-(9-anthryl)ethanol and 1-(9-anthryl)ethanol containing X electron-releasing and X electron-acceptor substituents attached to C-10, have been studied at the B3LYP/6-31+G(d,p) level of theory. Results analyzed in terms of the absolute gas-phase acidity, Fukui function, the local hard and soft acids and bases principle, and the molecular electrostatic potential, show that the central ring of the 9-anthryl group confers an ambident nucleophilic character and stabilizes the conjugated carbanion by electron-acceptor delocalization.
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http://dx.doi.org/10.3390/molecules180910254 | DOI Listing |
Inorg Chem
January 2025
Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
In this study, we apply TD-DFT and DFT calculations to explore the mechanistic details of O evolution in an artificial system that closely resembles Photosystem II (PSII). The reaction involves mononuclear Mn(III) complex [Mn(salpd)(OH)] and -benzoquinone under light-driven conditions. Our calculations reveal that the Schiff-base ligand salpd plays a crucial role in several key steps of the reaction, including the light-mediated oxidation of [Mn(salpd)(OH)] to [Mn(salpd)(OH)] by -benzoquinone, the subsequent oxidation of [Mn(salpd)(OH)] to the key Mn(V) intermediate [Mn(salpd)(O)], and the critical O-O bond formation step.
View Article and Find Full Text PDFACS Omega
January 2025
Laboratory of Theoretical Chemistry, Theoretical and Structural Physical Chemistry Unit, Namur Institute of Structured Matter (NISM), University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium.
Density functional theory (DFT) has been enacted to study the Diels-Alder reaction between 2,5-dimethylfuran (2,5-DMF), a direct product of biomass transformation, and acrolein and to analyze its thermodynamics, kinetics, and mechanism when catalyzed by a Lewis acid (LA), in comparison to the uncatalyzed reaction. The uncatalyzed reaction occurs via a typical one-step asynchronous process, corresponding to a normal electron demand (NED) mechanism, where acrolein is an electrophile whereas 2,5-DMF is a nucleophile. The small endo selectivity in solvents of low dielectric constants is replaced by a small exo selectivity in solvents with larger dielectric constants, such as DMSO.
View Article and Find Full Text PDFChem Sci
December 2024
Anhui Laboratory of Clean Catalytic Engineering, Anhui Laboratory of Functional Coordinated Complexes for Materials Chemistry and Application, College of Chemical and Environmental Engineering, Anhui Polytechnic University Wuhu 241000 Anhui P. R. China
The rare-earth metal dialkyl complexes (κ-L)RE(CHSiMe)·(THF) [RE = Lu(1a), Yb(1b), Er(1c), Y(1d), Dy(1e)] (L = 1-(2--CHNCHCH)-3-(2,6-PrCHN[double bond, length as m-dash]CH)-CHN) and the rare-earth metal monoalkyl complexes (κ-L)RE(CHSiMe)·(THF) [ = 0, RE = Lu(2a), Yb(2b); = 1, Er(2c), Y(2d), Dy(2e)], (κ-L)RE(CHSiMe)·THF [RE = Yb(3a), Er(3b), Y(3c), Dy(3d), Gd(3e)] (L = 1-(2--CHNCHCH)-3-(AdN[double bond, length as m-dash]CH)-CHN) (Ad = adamantyl, CH) have been synthesized and fully characterized. These complexes feature chelate ligands having a conjugated system (-C[double bond, length as m-dash]C-C[double bond, length as m-dash]N) with an sp carbon, which enables both electrophilic and nucleophilic carbon centres to be directly connected to the highly electrophilic rare-earth metal ions. The reactions of these complexes with different pyridine derivatives have been systematically investigated with the discovery of reactivity patterns distinct from those of previously reported transition metal complexes.
View Article and Find Full Text PDFMolecules
October 2024
Molecular Chemistry, Materials and Catalysis Laboratory, Faculty of Sciences and Technologies, Sultan Moulay Slimane University, BP 523, Beni-Mellal 23000, Morocco.
The hetero-Diels-Alder (HDA) reaction between the ambident heterodiene 3-methylene-2,4-chromandione (MCDO) and non-symmetric methyl vinyl ether (MVE) is investigated using the molecular electron density theory (MEDT) at the B3LYP/6-311G(d,p) computational level. The aim of this study is to gain insight into its molecular mechanism and to elucidate the factors that control the selectivity found experimentally. DFT-based reactivity indices reveal that MCDO exhibits strong electrophilic characteristics, while MVE displays a strong nucleophilic character.
View Article and Find Full Text PDFChem Asian J
January 2025
SupraSelen Laboratory, Department of Organic Chemistry, Institute of Chemistry, Universidade Federal Fluminense, Campus do Valonguinho, Niterói, RJ, 24020-141, Brazil.
A novel strategy to catalyze alkylation reactions through chalcogen bond interaction using a supramolecular structure is presented herein. Utilizing just 1.0 mol % of selenoxide-pillar[5]arene (P[5]SeO) as the catalyst we achieved efficient catalysis in the cyanation of benzyl bromide in water.
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