Host-guest complexes between cryptophane-C and chloromethanes revisited
| Autor: | Zoltan Takacs, Mária Šoltésová, Thierry Brotin, Jan Lang, Jozef Kowalewski, Jean-Pierre Dutasta |
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| Rok vydání: | 2012 |
| Předmět: |
Chloroform
Proton 010405 organic chemistry Stereochemistry Relaxation (NMR) General Chemistry 010402 general chemistry 01 natural sciences Cryptophane 0104 chemical sciences chemistry.chemical_compound Crystallography Molecular recognition chemistry General Materials Science Density functional theory Two-dimensional nuclear magnetic resonance spectroscopy Dichloromethane |
| Zdroj: | Magnetic Resonance in Chemistry. 51:19-31 |
| ISSN: | 0749-1581 |
| Popis: | Cryptophane-C is composed of two nonequivalent cyclotribenzylene caps, one of which contains methoxy group substituents on the phenyl rings. The two caps are connected by three OCH2CH2O linkers in an anti arrangement. Host–guest complexes of cryptophane-C with dichloromethane and chloroform in solution were investigated in detail by nuclear magnetic resonance techniques and density functional theory (DFT) calculations. Variable temperature proton and carbon-13 spectra show a variety of dynamic processes, such as guest exchange and host conformational transitions. The guest exchange was studied quantitatively by exchange spectroscopy measurements or by line-shape analysis. The conformational preferences of the guest-containing host were interpreted through cross-relaxation measurements, providing evidence of the gauche+2 and gauche−2 conformations of the linkers. In addition, the mobility of the chloroform guest inside the cavity was studied by carbon-13 relaxation experiments. Combining different types of evidence led to a detailed picture of molecular recognition, interpreted in terms of conformational selection. Copyright © 2012 John Wiley & Sons, Ltd. |
| Databáze: | OpenAIRE |
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