Y. Inouye et Y. Sakaino, Red, orange and yellow crystals of 4,5-bis(4-methoxyphenyl)-2-(3-nitro-phenyl)-1H-imidazole, ACT CRYST C, 56, 2000, pp. 884-887
Red non-solvate crystals of the title compound from ethanol, C23H19N3O4, or
ange solvate crystals from tert-butanol, C23H19N3O4. C4H10O, yellow solvate
crystals from dioxane-water, C23H19N3O4 . 0.5C(4)H(8)O(2), and intense yel
low solvate crystals from benzene-N,N'-dimethylformamide, C23H19N3O4 . C6H6
, differ from each other in their molecular conformation and hydrogen-bondi
ng scheme. The bathochromic shifts of the crystal color are explained by th
e molecular planarity and charge-transfer effect among the imidazole molecu
les.