Impact of storage time and solvent type on 2,2-diphenyl-1-picrylhydrazyl free radical stability

Abstract

The effect of storage time and solvent on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical stability was studied using electron spin resonance. Tetrahydrofuran affected the g-factor due to a rearrangement within the DPPH structure that changed the radical centre. There was also a change in the spins concentration when modifying the solvent and storage times. The more than 96 % decrease in spins after 12 weeks, consistent with a change in the pH and color, was attributed to the electron- and hydrogen-donor capabilities of the solvents, leading to a shift among the different DPPH ionic states. Tetralin instantly interacted with the DPPH capping many radicals.

Keywords

• 2,2-Diphenyl-1-picrylhydrazyl
• Solvent effect
• Electron spin resonance
• Storage effect
• Free radical