organic compounds
The crystal structures of two cocrystals composed of 4,4'-(fluorene-9,9-diyl)diphenol (C25H18O2) and 6-methyl-2H-pyridone (C6H7NO) are reported, namely 4,4'-(fluorene-9,9-diyl)diphenol-6-methyl-2H-pyridone (1/2), C25H18O2·2C6H7NO, (I), and 4,4'-(fluorene-9,9-diyl)diphenol-6-methyl-2H-pyridone-water (1/3/3), C25H18O2·3C6H7NO·3H2O, (II). In both cocrystals, the mutual orientation between two 6-methyl-2H-pyridone molecules in principle enables photodimerization, yet in both cases no photodimerization occurs. In cocrystal (I) this is probably due to poor orbital overlap, while in the case of cocrystal (II) it is suggested that the lack of reaction is due to the highly complex hydrogen-bonding network that exists in the structure.