Cubane-Based Dicationic Guest for Cucurbit[7/8]uril

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Cubane-Based Dicationic Guest for Cucurbit[7/8]uril

Popis výsledku v původním jazyce

The cationic derivatives of cage hydrocarbons including bicyclo[2.2.2]octane, adamantane or diamantane are the most attractive guest for cucurbit[n]urils (CBn). Cubane, another member of this intriguing cage-hydrocarbons family, has been neglected by supramolecular chemists until now. Since the first preparation of cubane by Eaton and Cole in 1964, its various derivatives such as nitrocubanes, peptides or polymers were prepared and studied.1 Moreover, in accordance with Eaton’s hypothesis, the cubane can replace benzene ring in the drug molecules to reduce potential toxicity. In contrast, there is only one supramolecular study on complex between -CD and cubane-derived guests reported in literature.2 We decided to prepare dicationic guest consisting of 1,4-disubstituated cubane cage and investigate its binding behavior towards CB7, CB8, and -CD. The new bisimidazolium salt G (for structure, see Figure 1) forms inclusion complexes with all abovementioned hosts in 1:1 molar ratio. The association constants values of G with CB7 and CB8 in pure water are (6.7±0.5)×1011 M−1, (1.5±0.2)×109 M−1, respectively. The solid-state structures of inclusion complexes were determined using single crystal X-ray diffraction analysis. As seen in Figure 1, the methylene bridges are more buried into the CB8 cavity compared to CB7 to bring the positively charged imidazolia closer to carbonyl portals and far from the portal centers. Consequently, the CB8 macrocycle is markedly elliptical in contrast to the essentially spherical CB7 within the G@CB7 complex. Upon these data, it can be inferred that positioning of cationic moiety in the portal center in not preferred in the CB8 complexes.

Název v anglickém jazyce

Cubane-Based Dicationic Guest for Cucurbit[7/8]uril

Popis výsledku anglicky

The cationic derivatives of cage hydrocarbons including bicyclo[2.2.2]octane, adamantane or diamantane are the most attractive guest for cucurbit[n]urils (CBn). Cubane, another member of this intriguing cage-hydrocarbons family, has been neglected by supramolecular chemists until now. Since the first preparation of cubane by Eaton and Cole in 1964, its various derivatives such as nitrocubanes, peptides or polymers were prepared and studied.1 Moreover, in accordance with Eaton’s hypothesis, the cubane can replace benzene ring in the drug molecules to reduce potential toxicity. In contrast, there is only one supramolecular study on complex between -CD and cubane-derived guests reported in literature.2 We decided to prepare dicationic guest consisting of 1,4-disubstituated cubane cage and investigate its binding behavior towards CB7, CB8, and -CD. The new bisimidazolium salt G (for structure, see Figure 1) forms inclusion complexes with all abovementioned hosts in 1:1 molar ratio. The association constants values of G with CB7 and CB8 in pure water are (6.7±0.5)×1011 M−1, (1.5±0.2)×109 M−1, respectively. The solid-state structures of inclusion complexes were determined using single crystal X-ray diffraction analysis. As seen in Figure 1, the methylene bridges are more buried into the CB8 cavity compared to CB7 to bring the positively charged imidazolia closer to carbonyl portals and far from the portal centers. Consequently, the CB8 macrocycle is markedly elliptical in contrast to the essentially spherical CB7 within the G@CB7 complex. Upon these data, it can be inferred that positioning of cationic moiety in the portal center in not preferred in the CB8 complexes.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10401 - Organic chemistry

Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů