Locked Energy of Axial to Equatorial Transformation Monitored by Exciplex and Excimer Fluorescence
2-<I>O</I>-<I>tert</I>-Butyldimethylsilyl-4,6-bispyrenoyl-<I>myo</I>-inositol-1,3,5-orthoformate (<B>1</B>) and 2-<I>O</I>-<I>tert</I>-butyldimethylsilyl-4-[(4-dimethylamino)benzoyl]-6-pyrenoyl-<I>myo</I>-inositol-1,3,5-orthoacetate (<B>2</B>) adopt unstable chair conformations with five substituents axial, in which the aromatic esters participate in π-stacking, and give excimer and exciplex fluorescence, respectively. Upon addition of acid, the orthoformate/orthoacetate lock is cleaved, which allows the inositol ring to switch to the more stable penta-equatorial chair conformation, with loss of exciplex/excimer fluorescence.
- Chemistry letters
Chemistry letters 35(8), 868-869, 2006-08-05
The Chemical Society of Japan