π-Methyl interactions and p-tert-butylcalix[4]arene-guest stability: NMR and crystallographic studies of cyclohexane and n-pentane inclusion compounds1

Despite the absence of π(guest)-methyl(host) interactions, p-tert-butylcalix[4]arene-cyclohexane [C12.5H17O, tetragonal, P 4n, a = 12.9446(4), c = 12.8156(4) Å, D c = 1.134 g cm−3, Z = 8, 1697 observed data I > 2.5σ(I), R = 0.054] and p-tert-butylcalix[4]arene-n-pentane [C12.25H17O, tetragonal, P 4n, a = 13.0230(19), c = 12.6190(12) Å, D c = 1.119 g cm−3, Z = 8, 1641 observed data I > 2.5σ(I), R = 0.048], characterized by NMR and X-ray diffraction, are stable and isoluble compounds.