Origin of the second harmonic generation in a supramolecular inclusion complex between p-nitroaniline and β-cyclodextrin

We report a combined NMR and crystallographic study of a supramolecular complex of β-cyclodextrin with p-nitroanaline. We show how the guest induces the formation a channel structure in the host cyclodextrin and discuss the guest molecule orientation and disorder in terms of the potential non-linear optical activity of the non-centrosymmetric crystals.