Encapsulation-Controlled Photoisomerization of a Styryl Derivative: Stereoselective Formation of the Anti Z-Isomer in the Cucurbit[7]uril Cavity.

Autor: Chernikova EY; Laboratory of Photoactive Supramolecular Systems, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia., Berdnikova DV; Universität Siegen, Organische Chemie II, Adolf-Reichwein-Str. 2, 57076, Siegen, Germany., Peregudov AS; Laboratory of Nuclear Magnetic Resonances, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia., Fedorova OA; Laboratory of Photoactive Supramolecular Systems, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia., Fedorov YV; Laboratory of Photoactive Supramolecular Systems, A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, Vavilova st. 28, 119991, Moscow, Russia.
Jazyk: angličtina
Zdroj: Chemphyschem : a European journal of chemical physics and physical chemistry [Chemphyschem] 2020 Mar 04; Vol. 21 (5), pp. 442-449. Date of Electronic Publication: 2020 Jan 31.
DOI: 10.1002/cphc.201901095
Abstrakt: The photochemical isomerization of a styrylpyridinium dye (SP) bearing an unsymmetrically attached benzo-15-crown-5 ether has been studied in aqueous solution in the absence and presence of cucurbit[7]uril (CB[7]). The detailed analysis of the UV/Vis and NMR spectra showes that the isomeric composition of the photostationary mixtures of SP can be modulated by the host-guest complexation with CB[7]. It was found that steric hindrance caused by encapsulation of SP in the host cavity induces the exclusive formation of the anti conformer of Z-SP in contrast with the mixture of both anti and syn conformers obtained during photoisomerization of the dye without CB[7]. Remarkably, the displacement of anti Z-SP from CB[7] does not lead to the transformation of the anti Z-isomer into the syn Z-isomer pointing out the conformational memory of the system. The results provide an interesting example of the supramolecular stereorecognition by the achiral CB[7] host.
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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