Conformational switching of resorcin[4]arene cavitands by protonation - Preliminary communication

Citation
Pj. Skinner et al., Conformational switching of resorcin[4]arene cavitands by protonation - Preliminary communication, HELV CHIM A, 84(7), 2001, pp. 2146-2153
Citations number
41
Categorie Soggetti
Chemistry & Analysis",Chemistry
Journal title
HELVETICA CHIMICA ACTA
ISSN journal
0018019X → ACNP
Volume
84
Issue
7
Year of publication
2001
Pages
2146 - 2153
Database
ISI
SICI code
0018-019X(2001)84:7<2146:CSORCB>2.0.ZU;2-T
Abstract
The synthesis of the quinoxaline-bridged resorcin[4]arene cavitand I was ac complished from 2-[3,5-di(tertbutyl)phenyl]acetaldehyde via formation of th e intermediate octol 2. Such cavitands are known to occur in an open 'kite' conformation at low temperature (< 213 K) but to adopt it 'vase' conformat ion at elevated temperatures (> 318 K). We discovered that protonation of c avitand I at room temperature by common acids, such as CF3COOH, also causes reversible switching from 'vase' to 'kite'. and that this conformational c hange can be conveniently monitored by both H-1-NMR and UV/VIS spectroscopy .