Encapsulation of Small Gas Molecules by Cryptophane-111 in Organic Solution. 1. Size- and Shape-Selective Complexation of Simple Hydrocarbons
| Autor: | Thierry Brotin, Boyd M. Goodson, Kathleen E. Chaffee, Heather A. Fogarty, Jean-Pierre Dutasta |
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| Přispěvatelé: | Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), 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) |
| Rok vydání: | 2009 |
| Předmět: |
Ethylene
010405 organic chemistry Chloromethane Analytical chemistry chemistry.chemical_element Trapping 010402 general chemistry Kinetic energy 01 natural sciences Cryptophane Methane 0104 chemical sciences [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry chemistry.chemical_compound Xenon chemistry 13. Climate action Molecule Physical and Theoretical Chemistry |
| Zdroj: | Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, The Royal Society of Chemistry, 2009, 113 (49), pp.13675-13684. ⟨10.1021/jp903452k⟩ Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 2009, 113 (49), pp.13675-13684. ⟨10.1021/jp903452k⟩ |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp903452k |
| Popis: | The reversible trapping of small hydrocarbons and other gases by cryptophane-111 (1) in organic solution was characterized with variable-temperature (1)H NMR spectroscopy. Characteristic spectral changes observed upon guest binding allowed kinetic and thermodynamic data to be readily extracted, permitting quantification and comparison of different host-guest interactions. Previous work (J. Am. Chem. Soc. 2007, 129, 10332) demonstrated that 1, the smallest cryptophane to date, forms a complex with xenon with remarkably high affinity. Presently, it is shown that 1 also exhibits slow exchange dynamics with methane at reduced temperatures (delta(bound) = -5.2 ppm) with an association constant K(a) = 148 M(-1) at 298 K. In contrast, ethane and ethylene are poorly recognized by 1 with K(a) values of only 2 M(-1) and 22 M(-1), respectively; moreover, chloromethane (whose molecular volume is similar to that of xenon, approximately 42 A(3)) is not observed to bind to 1. Separately, molecular hydrogen (H(2)) gas is observed to bind 1, but in contrast to other ligands presently studied, H(2) complexation is spectrally manifested by fast exchange throughout virtually the entire range of available conditions, as well as by a complex dependence of the guest (1)H resonance frequency upon temperature and host concentration. Taken together, these results establish 1 as a selective host for small gases, with implications for the design of size- and geometry-selective sensors targeted for various gas molecules. |
| Databáze: | OpenAIRE |
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