Keto–enol tautomeric equilibrium of an azo dye is shifted to the keto form as the solvent polarity is increased.
The paper mentioned in the title contains inaccuracies and misleading interpretations that misrepresent basic knowledge about tautomerism in azo dyes. This Letter gives a better understanding of the basic principles of the tautomerisation process.
Synthesis, Spectroscopic Studies and Biological Evaluation of Co(II), Ni(II), Cu(II) and Zr(IV) Complexes of Azo Dyes and Thiamine Hydrochloride as Antimicrobial Agents