Continuing our work on hydrazyl free radicals, five triphenylhydrazine derivatives, one a new compound, were synthesized to compare the electronic and molecular properties of these compounds, study the influence of substituents on the phenyl rings, and compare their properties with the parent hydrazines and corresponding anions. These hydrazines demonstrate both acid-base and redox properties. The hydrazine proton can be removed by base, yielding the corresponding anion and both the hydrazines and their anions can be oxidized to the corresponding hydrazyl free radicals. ESR spectra confirmed their formation and X-ray crystallography of one compound confirmed their structures.

Starting from dansyl-chloride, in reaction with 1,1-diphenylhydrazine and methoxyamine, two new fluorescent derivatives 1 and 2 were obtained and characterized by NMR, IR, UV-Vis, HR-MS, and fluorescence spectroscopy. The single-crystal X-ray structure was obtained for compound 2. Both compounds generate free radicals by oxidation, as demonstrated by ESR spectroscopy. Compound 1 generates the corresponding hydrazyl-persistent free radical, evidenced directly by ESR spectroscopy, while compound 2 generates in the first instance the methoxyaminyl short-lived free radical, which decomposes rapidly with the formation of the methoxy radical, evidenced by the ESR spin-trapping technique. By oxidation of compounds 1 and 2, their fluorescence is quenched.

No abstract