A reexamination of the low-temperature crystal structure of the p-tert-butylcalix[4]arene-toluene inclusion compound. Differences in spatial averaging with Cu and Mo Kalpha radiation.

The low-temperature crystal structure of the p-tert-butylcalix[4]arene-toluene inclusion compound, C(44)H(56)O(4) x C(7)H(8), exhibits significant guest-induced distortion of the host calixarene molecule. This distortion persists long enough to establish a correlation in the orientation of guests in adjacent host molecules. Remarkably, the space group and unit cell that best describe the structure appear to depend on the wavelength of the incident radiation. This behaviour appears to arise from spatial averaging over the different scattering volumes required to establish the diffraction peaks.