Synthesis and Optical Properties of 2-(1H-Imidazo [4,5-] Phenazin-2-yl) Phenol Derivatives
A convenient one-pot process to synthesize 2-(1H-imidazo[4,5-b]phenazin-2-yl) phenol derivatives 3a-e with substitute (s) X (X = H, CH3O, CH2OH, Cl, Br) via the reaction of 2-hydroxy aromatic aldehydes with phenazine-2,3-diamines in the presence of manganese(III) acetate at room temperature in 80-85% yield was developed. Meanwhile, the ultraviolet absorption and the fluorescent spectra of these o-hydroxy derivatives of 1H-imidazo[4,5-b] phenazin were measured in methanol. Compared with the dual emission characteristics of 2-(2-hydroxy-phenyl) benzimidazole derivatives, only one fluorescence band with a peak wavelength of 540nm was observed and that the Stokes shifts were around 136-140 nm for 3a-e.
Y. J. Lei et al., "Synthesis and Optical Properties of 2-(1H-Imidazo [4,5-] Phenazin-2-yl) Phenol Derivatives", Advanced Materials Research, Vols. 311-313, pp. 1286-1289, 2011