EPR and Potentiometric Studies of the Interaction of Cr(VI) and Cr(V) with D-ribose-5-phosphate and nucleotides

MARCELA RIZZOTTO,; VIRTUDES MORENO,; SANDRA SIGNORELLA,; DAIER, VERÓNICA; LUIS SALA,

POLYHEDRON

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: www.elsevier.com/locate/poly; Año: 2000 vol. 19 p. 417 - 423

0277-5387

Cr(VI) and Cr(V) interaction with -ribose 5′-monophosphate (R5P), adenosine 5′-monophosphate (AMP), cytidine 5′-monophosphate (CMP) and 2′-deoxythymidine 5′-monophosphate (dTMP) was studied by electron paramagnetic resonance (EPR) spectroscopy (Cr(V)) and potentiometry (Cr(VI)) in aqueous solutions. The EPR spectra showed a narrow but composed signal. The Cr(V) signals showed experimental giso and 53Cr Aiso values that are typical of five-coordinate oxochromate(V) complexes. Potentiometric studies of CMP and AMP in the presence and absence of potassium dichromate allow us to suggest the presence of three species of S–Cr(VI), differing in their degree of protonation.