1. Diazenium Betaines Derived from the Stable Free Radical DPPH with Diradicaloid Behavior
- Author
-
Adela F. Dobre, Augustin M. Mădălan, Anamaria Hanganu, and Petre Ionita
- Subjects
free radical ,DPPH ,betaine ,synthesis ,structural characterization ,ESR ,Chemistry ,QD1-999 - Abstract
Starting from the well known stable free radical DPPH (or its reduced counterpart, 2,2-diphenyl-1-picryl-hydrazine) and several amino derivatives, novel zwitterionic compounds (diazenium betaines) were obtained and characterized by different means, like NMR, IR, MS, and UV–Vis. These betaines are highly intense blue-colored compounds that can be easily reduced by ascorbic acid (vitamin C) or sodium ascorbate to their corresponding para-phenyl substituted derivatives of DPPH, which have a yellow color. Most of such redox processes were found to be reversible. However, the oxidation of 2-p-aminophenyl-2-phenyl-1-picryl-hydrazine led to an azo-derivative of DPPH diradical, and its structure was unveiled by X-ray monocrystal diffraction. Possible diradicaloid behavior is also discussed.
- Published
- 2024
- Full Text
- View/download PDF