Novel Dimers of 2,2′-(m-Phenylene)bis(4,5-diphenyl-1-imidazolyl) Diradical

Abstract

Abstract The oxidation of 2,2′-(m-phenylene)bis(4,5-diphenylimidazole) 1 with potassium ferricyanide in benzene-aqueous KOH heterogeneous solution gave the diradical dimers 2 and 3. The dimer 2 showed photochromic and piezochromic properties, whereas the dimer 3 has only photochromic property. The structure of the dimers was deduced by NMR analyses. The X-ray structural analysis revealed that the dimer 3 has a novel syn-[3.3]metacyclophane structure.