Binary amorphous solids consisting of 2,4,6-triarylphenoxyl radicals and their dimers

Although molecular amorphous materials represent an important area of research in solid-state chemistry, studies pertaining to these systems have been restricted almost exclusively to amorphous solids based on a single molecule. In this study, we found that, while the 2,4,6-bis(4-tert-butylphenyl)phenoxyl radical (2M) and its dimer (2D) did not give single-component amorphous solids, they rapidly formed the corresponding binary amorphous solid IIa following their condensation from benzene, dichloromethane, chloroform, and ethyl acetate solutions. The formation of IIa could be attributed to the good solubilities of 2M and 2D in these solvents and the high packing efficiencies of these amorphous solids. IIa was also obtained when crystals of 2D (IIb) were ground together. The solid-state formation of IIa would not only involve the locational exchange of 2M and 2D, but would also involve chemical exchanges.