Abstract:
Trithiocyanuric acid (TCA) and 4,4'-bipyridyl (BP) form hydrogen-bonded co-crystals with aromatic compounds such as benzene, toluene, p-xylene and anthracene. The TCA-BP co-crystal is composed of cavities formed by the N-H ... N hydrogen bonds between the two molecules, and the three-dimensional structure contains channels of approximately 10 Angstrom where aromatic molecules are accommodated. The molar ratios of TCA, BP and the aromatic compound in the co-crystals are 2 : 1 : 1 or 2 : 1 : 0.5. Benzene, toluene and p-xylene are removed from the channels around 190, 183 and 170 degrees C respectively, and these aromatic guests can be reintroduced into the empty channels of the apo-hosts. The apo-hosts with empty channels have reasonable thermal stability and exhibit shape selectivity in that the empty channels accommodate p-xylene but not m- or o-xylene or mesitylene.
