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Cucurbiturils Monofunctionalized on the Methylene Bridge and Their Host‐Guest Properties
Author(s) -
Kandrnálová Markéta,
Šindelář Vladimír
Publication year - 2021
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202100705
Subject(s) - cucurbituril , chemistry , substituent , supramolecular chemistry , isothermal titration calorimetry , methylene , methylene bridge , titration , host–guest chemistry , binding constant , polymer chemistry , stereochemistry , organic chemistry , molecule , binding site , biochemistry
Monofunctionalization of cucurbiturils is essential for transferring these potent supramolecular macrocyclic hosts into real‐world application. Here, we present the synthesis of cucurbit[6]urils 1 and 2 in which one methylene bridge is modified by a single substituent containing a nitro or an ammonium group. We investigated host–guest properties in water and 0.2 M NaCl using 1 H NMR and isothermal titration calorimetry, particularly for 2 . The macrocycle 2 self‐associated into dimeric aggregates in pure water, but readily disassembled in the presence of NaCl or organic cations. Cucurbit[7]uril was able to encapsulate the ammonium substituent of 2 inside its cavity resulting in a complex of 1 : 1 stoichiometry with an association constant of 3.1×10 5 M −1 . The presented host–guest properties together with further possible derivatization showcase the potential of cucurbiturils modified in the methylene position such as 1 and 2 for the development of advanced supramolecular systems.