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A Study of the Interaction Between Cucurbit[8]uril and Alkyl‐Substituted 4‐Pyrrolidinopyridinium Salts
Author(s) -
Xu Weitao,
Kan Jinglan,
Yang Bo,
Prior Timothy J.,
Bian Bing,
Xiao Xin,
Tao Zhu,
Redshaw Carl
Publication year - 2019
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201801498
Subject(s) - chemistry , isothermal titration calorimetry , alkyl , crystallography , pyridinium , dimer , molecule , aqueous solution , stereochemistry , spectroscopy , medicinal chemistry , organic chemistry , physics , quantum mechanics
The interaction between cucuribit[8]uril (Q[8]) and a series of 4‐pyrrolidinopyridinium salts bearing aliphatic substituents at the pyridinium nitrogen, namely 4‐(C 4 H 8 N)C 5 H 5 NRBr, where R=Et (g1), n ‐butyl (g2), n ‐pentyl (g3), n ‐hexyl (g4), n ‐octyl (g5), n ‐dodecyl (g6), has been studied in aqueous solution by 1 H NMR spectroscopy, electronic absorption spectroscopy, isothermal titration calorimetry and mass spectrometry. Single crystal X‐ray diffraction revealed the structure of the host–guest complexes for g1, g2, g3, and g5. In each case, the Q[8] contains two guest molecules in a centrosymmetric dimer. The orientation of the guest molecule changes as the alkyl chain increases in length. Interestingly, in the solid state, the inclusion complexes identified are different from those observed in solution, and furthermore, in the case of g3, Q[8] exhibits two different interactions with the guest. In solution, the length of the alkyl chain plays a significant role in determining the type of host–guest interaction present.