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Poly(phenylene) and m ‐Terphenyl as Powerful Protecting Groups for the Preparation of Stable Organic Hydroxides
Author(s) -
Wright Andrew G.,
Weissbach Thomas,
Holdcroft Steven
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201511184
Subject(s) - hydroxide , chemistry , terphenyl , barium hydroxide , phenylene , chemical stability , potassium hydroxide , polymer , inorganic chemistry , bromine , conductivity , polymer chemistry , organic chemistry
Four benzimidazolium hydroxide compounds, in which the C2‐position is attached to a phenyl group possessing hydrogen, bromine, methyl groups, or phenyl groups at the ortho positions, are prepared and investigated for stability in a quantitative alkaline stability test. The differences between the stability of the various protecting groups in caustic solutions are rationalized on the basis of their crystal structures and DFT calculations. The highest stability was observed for the m ‐terphenyl‐protected benzimidazolium, showing a half‐life in 3 m NaOD/CD 3 OD/D 2 O at 80 °C of 3240 h. A high‐molecular‐weight polymer analogue of this model compound is prepared that exhibits excellent mechanical properties, high ionic conductivity and ion‐exchange capacity, as well as remarkable hydroxide stability in alkaline solutions: only 5 % degradation after 168 h in 2 m KOH at 80 °C. This is the most stable hydroxide‐conducting benzimidazolium polymer to date.