Mass spectrometrical and quantum‐chemical study of pentafluorophenylhydrazones

Twenty‐one pentafluorphenylhydrazones have been analyzed by means of tandem mass spectrometry (ESI MS/MS) conditions to compare their fragmentations with those ones obtained from quantum‐chemical calculations of the hydrazone moiety depending on the substitution from the aldehyde site. The hydrazone N–N bond is disrupted under such conditions, and these results are in accordance with the facts that an electron‐rich particle, such as an anion and or radical in a solution, can cause this disruption and simultaneous defluorination in para‐position of the hydrazone part of the molecule.