A 13C cross polarization–magic angle spinning n.m.r. study of the structure of p-t-butylcalix[4]arene– toluene clathrate in the crystalline state

Abstract

¹³ C Cross polarization–magic angle spinning n.m.r. spectra of p-t-butylcalix[4]arene and p-t-butylcalix[4]arene–toluene clathrate in the solid state show that the ¹³C chemical shift of the methyl carbon of toluene is displaced 6.2 p.p.m. upfield of that of free toluene which agrees well with the calculated value based on the ring current effect of the phenyl groups of the calixarene; the ¹³C chemical shifts of other carbons were also assigned.