Synthesis and characterization of a new hydrazyl free radical, a formyl-derivative of DPPH

Starting from 2,2-diphenyl-1-(2,4,6-trinitropheyl)hydrazine and urotropine in the presence of trifluoracetic acid it was obtained a formyl derivative as a yellow solid, that can form under oxidative condition the persistent hydrazyl free radical 2-(p-formyl-phenyl)-2-phenyl-1-(2,4,6-trinitrophenyl)hydrazyl having a violet colour. The same formyl hydrazine derivative in the presence of a base forms the corresponding anion with a red-brown colour. The new compounds were characterized by appropriate means, like NMR, IR, UV-VIS, ESR.