American Chemical Society
ol901472j_si_001.cif (35.59 kB)

Restricted Rotation of tert-Butyl Groups in Sterically Crowded Methylene-Functionalized Calix[4]arenes

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posted on 2009-08-20, 00:00 authored by Lev Kuno, Silvio E. Biali
The crowded methylene-functionalized calix[4]arenes 4 and 5 display restricted rotation of the tert-butyl substituents at the bridges. At low temperatures, separate signals were observed for the methyls of these groups in the 1H NMR spectra.