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New guests for the cucurbit[8]uril host. Formation of G 2 H ternary complexes
Author(s) -
Senler Sanem,
Cui Lu,
Broomes Ana Michelle,
Smith Erika L.,
Wilson James N.,
Kaifer Angel E.
Publication year - 2012
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.2928
Subject(s) - chemistry , pyridinium , ternary operation , iodide , stoichiometry , bromide , pyridinium compounds , proton nmr , denticity , crystallography , ternary complex , medicinal chemistry , stereochemistry , inorganic chemistry , organic chemistry , crystal structure , enzyme , computer science , programming language
On the basis of the highly stable G 2 H (2 : 1) ternary complex formed by two methyl viologen cation radicals inside the cavity of cucurbit[8]uril, we prepared three monocationic 4‐phenylpyridinium derivatives: 1‐(hydroxyethyl)‐4‐phenyl‐pyridinium ( 1+ ) bromide, 1‐(octaethyleneglycol)‐4‐phenyl‐pyridinium ( 2+ ) chloride, and 4‐[4‐(methoxymethoxy)phenyl]pyridinium ( 3+ ) iodide, as possible guests for 2 : 1 complexation inside cucurbit[8]uril. We also investigated a fourth monocationic guest ( 4+ ), in which a central vinylidene group is inserted to elongate the 4‐phenyl‐pyridinium residue. Using 1 H NMR and UV–Vis spectroscopic data and mass spectrometric data, we obtained unequivocal evidence for the formation of G 2 H (2 : 1) ternary complexes in all cases. The stoichiometry of the complexes was further verified by continuous variation (Job) plots, and in some cases, high resolution ESI‐MS spectrometric data. Diffusion coefficient measurements, using 1 H NMR pulse gradient spin echo techniques, yielded values consistent with the formation and expected structures of the ternary complexes. Copyright © 2012 John Wiley & Sons, Ltd.