Frustrated behavior of Lewis/Brønsted pairs inside molecular cages

Autor: C. Li, A.-D. Manick, J.-P. Dutasta, X. Bugaut, B. Chatelet, A. Martinez
Přispěvatelé: Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Sichuan University of Science & Engineering, Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ANR-19-CE07-0024,Co-LAB,Acide/base de Lewis confinées(2019)
Rok vydání: 2022
Předmět:
Zdroj: Organic Chemistry Frontiers
Organic Chemistry Frontiers, 2022, 9, pp.1826-1836. ⟨10.1039/d2qo00011c⟩
ISSN: 2052-4129
DOI: 10.1039/d2qo00011c
Popis: International audience; Different endohedrally functionalized cages were designed to investigate the effects of the size and shape of molecular cavities on the frustrated behavior of Lewis/Brønsted acid-base pairs and on catalytic activities. The shape of the inner space above the reactive center was found to strongly affect these properties. When an acidic azaphosphatrane is inserted in the smallest cage and associated with t-BuOK or − CD 2 CN bases, a frustrated Brønsted pair is obtained. In contrast, when encapsulated in the medium or large cage, the P-H + azaphosphatrane acid is easily deprotonated under the same conditions. The resulting two supramolecular Verkade's superbases lead to frustrated Lewis pair systems in the presence of TiCl 4. Furthermore, the larger cage displays better catalytic activity in the MBH reaction. Thus, a small change in the cage size, which only differs by one methylene group in the linkers, can influence the frustrated properties of the related systems, and a right balance between the frustrated behavior and cage flexibility has to be reached to obtain optimal systems for catalytic applications.
Databáze: OpenAIRE
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