Kinetics and mechanism of the chromic oxidation of myo-inositol

MABEL IRENE SANTORO; CAFFARATTI E; SALAS-PEREGRIN, J. M.; KORECZ L; ROCKENBAUER A; SIGNORELLA, SANDRA ROSANNA; SALA, LUIS FEDERICO

Polyhedron

Elsevier

Año: 2007 vol. 26 p. 169 - 177

0277-5387

The oxidation of D-myo-inositol (Myo) by CrVI yields the inosose and Cr3+ as final products when an excess of cyclitol over CrVI is used. The redox reaction takes place through the combination of CrVI ® CrIV ® CrII and CrVI ® CrIV ® CrIII pathways. Intermediacy of CrIV was evidenced by the detection of CrO22+, formed by reaction of CrII with O2. The EPR spectra show that five- and six-co-ordinate oxo-CrV intermediates are formed, with the cyclitol acting as bidentate ligand. Penta-co-ordinate oxo-CrV species are present at any [H+], whereas hexa-co-ordinate ones are only observed at pH < 1, where rapidly decompose to the redox products. At higher pH, where hexa-co-ordinate oxo-CrV species are not observed, oxo-CrV bischelates are stable enough to remain long time in solution.