An iterative hydride reduction/oxidation process was promoted under ambient conditions by a quasi-planar iminium cation rigidified by two concatenated quinoline units. The iminium proton was fixed by hydrogen bonding from neighboring quinoline nitrogen atoms, rendering the imine highly susceptible to hydride reduction with weak reductants, e.g., 1,4-dihydropyridines. The thus-formed amine was readily oxidized by molecular oxygen to regenerate the quasi-planar iminium cation under ambient conditions. This process was exploited for catalytic oxidation of 1,4-dihydropyridines as well as 9,10-dihydroacridine to highlight an intriguing rigidity-driven catalysis.
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http://dx.doi.org/10.1248/cpb.c22-00215 | DOI Listing |
J Mol Model
October 2024
Departamento de Físico-Química, Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, 4070139, Chile.
Context: The CO activation by low-valent group 14 catalysts encompasses the rupture of varied covalent bonds in a single transition state through a concerted pathway. The bond between the central main group atom and the hydride in the complex is elongated to trigger the formation of the C-H bond with CO accompanied by the concomitant formation of the E-O bond between the complex and CO to lead the corresponding formate product. Prior studies have established that besides the apolar nature of CO , its initial interaction with the complex is primarily governed by electrostatic interactions.
View Article and Find Full Text PDFJ Org Chem
November 2024
Department of Chemistry, Scripps Research, La Jolla, California 92037, United States.
J Am Chem Soc
November 2023
Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States.
Molecular main-group hydride catalysts are attractive as cheap and Earth-abundant alternatives to transition-metal analogues. In the case of the latter, specific steric and electronic tuning of the metal center through ligand choice has enabled the iterative and rational development of superior catalysts. Analogously, a deeper understanding of electronic structure-activity relationships for molecular main-group hydrides should facilitate the development of superior main-group hydride catalysts.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
September 2022
Faculty of Pharmacy, Keio University.
An iterative hydride reduction/oxidation process was promoted under ambient conditions by a quasi-planar iminium cation rigidified by two concatenated quinoline units. The iminium proton was fixed by hydrogen bonding from neighboring quinoline nitrogen atoms, rendering the imine highly susceptible to hydride reduction with weak reductants, e.g.
View Article and Find Full Text PDFJ Chem Phys
May 2022
Lehrstuhl für Theoretische Chemie, Universität Erlangen-Nürnberg, Egerlandstr. 3, D-91058 Erlangen, Germany.
We present a Kohn-Sham (KS) inversion approach to construct KS exchange-correlation potentials corresponding to given electron densities. This method is based on an iterative procedure using linear response to update potentials. All involved quantities, i.
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