Solvent-controlled formation of alkali and alkali-earth-secured cucurbituril/guest trimers

0575698 - ÚOCHB 2024 RIV GB eng J - Článek v odborném periodiku
Lončarić, Doroteja - Movahedifar, F. - Štoček, Jakub Radek - Dračínský, Martin - Cvačka, Josef - Guan, S. - Bythell, B. J. - Císařová, I. - Masson, E. - Kaleta, Jiří
Solvent-controlled formation of alkali and alkali-earth-secured cucurbituril/guest trimers.
Chemical Science. Roč. 14, č. 35 (2023), s. 9258-9266. ISSN 2041-6520. E-ISSN 2041-6539
Grant CEP: GA ČR(CZ) GA20-13745S; GA MŠMT(CZ) LTAUSA19120
Institucionální podpora: RVO:61388963
Klíčová slova: solvation free-energies * crystal structures * model
Obor OECD: Organic chemistry
Impakt faktor: 8.4, rok: 2022
Způsob publikování: Open access
https://doi.org/10.1039/D3SC02032K

Cucurbit[7]uril (CB[7]) encapsulates adamantyl and trimethylsilyl substituents of positively charged guests in dimethyl sulfoxide (DMSO). Unlike in water or deuterium oxide, addition of a selection of alkali and alkali-earth cations with van der Waals radii between 1.0 and 1.4 Å (Na+, K+, Ca2+, Sr2+, Ba2+ and Eu3+) to the CB[7]/guest complexes triggers their cation-mediated trimerization, a process that is very slow on the nuclear magnetic resonance (NMR) time scale. Smaller (Li+, Mg2+) or larger cations (Rb+, Cs+ or NH4+) are inert. The trimers display extensive CH-O interactions between the equatorial and pseudo-equatorial hydrogens of CB[7] and the carbonyl rim of the neighboring CB[7] unit in the trimer, and a deeply nested cation between the three interacting carbonylated CB[7] rims, a counteranion is likely perched in the shallow cavity formed by the three outer walls of CB[7] in the trimer. Remarkably, a guest must occupy the cavity of CB[7] for trimerization to take place. Using a combination of semi-empirical and density functional theory techniques in conjunction with continuum solvation models, we showed that trimerization is favored in DMSO, and not in water, because the penalty for the partial desolvation of three of the six CB[7] portals upon aggregation into a trimer is less unfavorable in DMSO compared to water.
Trvalý link: https://hdl.handle.net/11104/0345437


Vědecká data: CCDC, CCDC, CCDC, CCDC