Structural effects on the solid-state photodimerization of 5-chloro and 5-nitro-2(1H)-pyridone in molecular compounds

The preparation and crystal structure of six molecular compounds consist of light-stable host mole- cules ((1-cyclohexyl-4-hydroxybenzene, 1,1,6,6-tetrapheny l-2,4-hexadiyne-1,6-diol, 4-((10-(4-(ethoxycarbonyl)phen- oxy)decyl)oxy)benzene, 1,2,4,5-benzenetetracarboxylic acid, resorcinol) and light-sensitive guest molecules ((5-chloro- 2(1H)-pyridone or 5-nitro-2(1H)-pyridone) are described in light of their failure to undergo (4 ? 4) photodimerization in the solid-state upon irradiation with UV light. Unlike in many cases were pyridone and its derivatives undergo such dimerization in the solid-state due to the packing arrangement in the crystalline form in which the geometric requirement for photodimerization meet, the compounds described here failed to pack in ways to enable such pho- todimerization. The distances between the potentially reactive atoms ranged from 4.620 to 8.408 Awhich are too long to react.