aDepartment of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
bNational Institute of Laser Enhanced Science, University of Cairo, Giza, Egypt
Abstract:
Three series of 3,7-bis(arylazo)-6-methyl-2-phenyl-1H-imidazo-[1,2-b]pyrazoles were prepared starting from N-aryl 2-oxo-2-phenylethanehydrazonoyl bromides and 5-amino-4-arylazo-3-methyl pyrazoles. The acid dissociation constants pK and pK* in both the ground and excited states, respectively, were determined and correlated with the Hammett equation. The results of such correlations together with the spectroscopic data indicated that the title compounds exist predominantly in the 1H-bis(arylazo) form in both ground and excited states.