Szupiluk A, Bernatowicz P, Ratajczyk T, Szymanski S.
J Phys Chem A. 2016 Dec 27. doi: 10.1021/acs.jpca.6b11812. [Epub ahead of print]Hindered rotation of the -NH3+ group in a sterically crowded molecular environment was frozen on the NMR time scale. These effects were observed for solutions of 1,2,3,4-tetrabromotriptycyl-9-ammonium tetrafluoroborate in tetrahydrofuran with and without excess of HBF4. In the absence of acid, the hindered rotation is accompanied by a number of other effects originating in part from practically non ... Read More