Cocrystallization of pyrogallol[4]arenes with 1-(2-pyridylazo)-2-naphthol

Cocrystallizations of pyrogallol[4] arenes and 1-(2-pyridylazo)-2-naphthol (PAN) are investigated herein in order to determine the effect of aliphatic tail-length and solvent on crystal packing, probe orientation, and pyrogallol[4] arene bowl-shape. It is seen that solvent affects the final ratio of PAN to pyrogallol[4] arene, while aliphatic tail-length influences the crystal packing, C-H center dot center dot center dot pi interactions, and overall hydrogen bonding. With an aliphatic tail-length of one carbon atom, there is an atypical bilayer structure. As the aliphatic tail-length increases, the resulting cocrystals have the characteristic bilayer structure as well as an increased number of C-H center dot center dot center dot pi interactions and decreased hydrogen bonding with the PAN molecules.