t-Butylcalix[4]arene host-guest compounds: Structure and dynamics

Despite the proliferation of structural studies on calixarene host-guest compounds, some important structural details remain obscure. In particular, the ubiquitous disorder of the calix t-butyl group often hinders a detailed determination of the non-bonding interactions between host and guest. We propose and develop a synoptic approach in which several complementary characterization techniques (X-ray diffraction and NMR) provide a powerful means of assessing the interplay of structure and dynamics in calixarene-guest compounds. The simple t-butylcalix[4]arene-guest compounds (guest = toluene, nitrobenzene, cyclohexane, n-pentane, 1-chlorobutane) are examined with this approach, and new structural and dynamic features are uncovered.