Redox Activity of Chromium (III) with Picolinic Acid, Dipicolic Acid and L-Phenylalanine in Polar Aprotic Media

<p>Cyclic voltammetry (CV) was used to evaluate the electrochemical behavior of Cr (III) complexes in presence and absence of Br&oslash;nsted acid and free radical formation on them in polar aprotic media.&nbsp; Tris- (2-pyridincarboxilate) of chromium (III) (Cr(pic)₃) and, Cr(pic)₃ and Bis-(2,6-pyridinedicarboxylchromate (III) of sodium&nbsp; (Cr(dipic)₂), exhibit two reversible coupled redox, where the anodic wave corresponds to the electrochemical response of the metal center, and the cathodic one is related to the ligand groups of different natural chemistry.&nbsp; Tris-(2-amino-3-phenylpropanoate) of chromium (III) (Cr(phen)₃) complex has an irreversible electrochemical behavior out of the range of reductant agents, showing very poor response of the ligand.&nbsp; It is considered highly stable and very difficult to oxidize.&nbsp; When the CV was carried out in presence of ligands as Br&oslash;nsted acid, the release of proton occurs and complex could adopt it through ligand coordinated.&nbsp; In order to understand radical formation in the complexes.&nbsp; N, N-dimethyl-p-nitrosoaniline (R-NO) was introducing as spin trap in presence of Chromium (III) complexes, forming an adduct with the ligand coordinated.&nbsp; All the electrochemical reaction change from their original state, but Cr(phen)₃ shows more wave relatives to the metal center: Cr(III) - Cr(IV), L-Phen, Cr(IV) - Cr(V), Cr(V)-Cr(IV) and Cr(IV) - Cr(III).</p>