CHEMICAL KINETICS, PHOTOCHEMICAL AND PHOTOPHYSICAL PROCESSES IN SOLUTIONS

Coordinators: Alberto L. Capparelli and Mario R. Féliz

The main goals of the research activities of this group are the study of fundamental processes in chemical kinetics, photochemistry of photophysics in liquid phase as well as the development of activities foreseen to be applied in environmental chemistry - photochemical remediation of waters and air, fine chemistry and biotechnology.
These studies are performed using several techniques: flash photolysis technique, laser flash photolysis, stopped flow, temperature jump, etc.
The research activities cover up the following aspects:
• Study of photochemical and photophysical processes involving coordination compounds, particularly macrocycles of transition metal complexes as well as the role of Charge Transfer Excited States in their photochemical properites.
• Advanced oxidation technologies for degrading pollutants in aqueous phase (Fenton, UV/H2O2, photo Fenton, etc). Evaluation of the efficiency of photodegradation methods.
• Reactions involving pollutants and inorganic radicals of environmental relevance.
• Study of the interaction of humic substances with reactive oxygen species and inorganic radicals.
• Study of the photosensitized generation of reactive oxygen species. Evaluation of the role of these compounds on processes of biomedical interest (such as folic acid, pterin derivatives, etc. ).

Research Staff

Ezequiel Wolcan, Yanina Rosso
Carolina Lorente, Gustavo Ruiz
María Paula Juliarena, Laura S. Villata
Fernando S. García Einschlag, Luciano Carlos
Paula Caregnato, Laura Dántola
Gabriela Petroselli, Larisa Bracco
Verónica Mora, Pedro David Gara
Valeria Arce, María Laura Dell' Arciprete
Daniela Nichela, Mariana Vignoni
M. Paula Denofrio, Marcos Pedemonte
Tobias M. Schuler, Andrea Berkovik
Manuel Llansola Portolés, Ulises Fagioli
Marcela Martin, Jorge López

Selected publications in the frame of this project (2007 - 2008)

* “Intercalation of fac-[(4-4' bpyRe(CO3)(dppz)+, dppz = dipyridil[3,2-a:2' 3'-c]phenazine, en polynucleotides. On the UV-vis phoophysics of the Re(I) intercalate and the redox reactions with pulse radiolysis-generated radicals”.
G.T. Ruiz, M.P. Juliarena, R.O. Lezna, E. Wolcan, M.R. Féliz y G. Ferraudi
Journal of Chemical Society. Dalton Transaction 20, 2020-2029 (2007).

* “Kinetic and spectroscopic observations on the azidyl radical oxidation of fac-(Lspec)Re(I)(CO3)(Lacep) to fac-(Lspect)Re(II)(CO)3(Lacep)”.
G.T. Ruiz, M.P. Juliarena, E. Wolcan y G. Ferraudi
Inorganica Chimica Acta 360, 3681-3687 (2007).

* “Inhibition of the fac-(RCO2)Re(I)(CO3)(bis-azine) photodecarboxilation of the carboxylate ligand, RCO2-, when R is a strong electron donating group. The thermal and photochemical properties of complexes where R = ferrocene- and 4-(N,N-dimethylamino)benzyl”.
M.P. Juliarena, G.T. Ruiz, E. Wolcan, R.O. Lezna, M.R. Féliz y G. Ferraudi
Organometallics 26, 272-280 (2007).

* “Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1?g)): Physical Quenching and Chemical Reaction”.
F.M. Cabrerizo, M.L. Dántola, G. Petroselli, A.L. Capparelli, A.H. Thomas, A.M. Braun, C. Lorente y E. Oliveros
Photochemistry and Photobiology 83, 526-534 (2007).

* “Photosensitization of 2' -deoxyadenosine-5' -monophosphate by pterina”.
G. Petroselli, R. Erra-Balsells, F.M. Cabrerizo, C. Lorente, A.L. Capparelli, A.M. Braun, E. Oliveros y A.H. Thomas
Organic and Biomolecular Chemistry 5, 2792-2799 (2007).

* “On the nature of the redox products of 4-((CH3)2N)C6H4-CO2- and 4-((CH3)2N)C6H4-CO2-Re(CO)3(1,10-phenanthroline): a spectroelectrochemical, pulse radiolysis and flash photochemical study”.
M.P. Juliarena, R.O. Lezna, G.T. Ruiz, M.R. Feliz, G.I. Ferraudi y E. Wolcan
Polyhedron 27, 1471-1478 (2008).

* “Reaction between 7,8-dihydropterins and hydrogen peroxide under physiological conditions”.
M.L. Dántola, T.M. Schuler, M.P. Denofrio, M. Vignoni, A.L. Capparelli, C. Lorente y A.H. Thomas
Tetrahedron, 64, 8692-8699 (2008).

* “Stability of 7,8-dihydropterins in air-equilibrated aqueous solutions”.
M.L. Dántola, M. Vignoni, A.L. Capparelli, C. Lorente y A.H. Thomas
Helvetica Chimica Acta 91, 379-580 (2008).

* “Oxidation of 2'-deoxyguanosine 5'-monophosphate photoinduced by pterin: type I versus type II mechanism”.
G. Petroselli, M.L. Dántola, F.M. Cabrerizo, A.L. Capparelli, C. Lorente, E. Oliveros y A.H. Thomas.
Journal of the American Chemical Society 130, 3001-3011 (2008).

* “Intermediate distributions and primary yields of phenolic products in nitrobenzene degradation by fenton's reagent”.
L. Carlos, D. Fabbri, A.L. Capparelli, A. Bianco Prevot, E. Pramauro y F.S. García Einschlag
Chemosphere 72(6), 952-958 (2008).

* “Autocatalytic oxidation of nitrobenzene using hydrogen peroxide and Fe(III)”.
D. Nichela, L. Carlos y F. García Einschlag
Applied Catalysis B: Environmental 82, 11-18 (2008).

* “Tungsten Doped TiO2 vs. Pure TiO2 Photocatalysts: Effects on Photobleaching Kinetics and Mechanism”.
N. Couselo, F. García Einschlag, R. Candal y M. Jobbagy
The Journal of Physical Chemistry C 112, 1094-1100 (2008).