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SPECTROELECTROCHEMISTRY OF COORDINATON COMPOUNDS
Coordinator:
Dr. Reynaldo O. Lezna
Spectroelectrochemistry of coordination compounds with a view to relating their electrochemical and spectroscopic properties to their photochemical
and photophysical behaviors.
Oligonuclear complexes made by Ru(II) polypyridine components have been extensively investigated because they play a key role in the development of
multi-component (supramolecular) artificial systems for photochemical energy conversion and other related photonic devices.
A large diversity of monomeric, oligomeric and polymeric structures of [Ru(bpy)3]2+, or related complexes, are listed in the literature. However
reactions of practical interest such as oxygen reduction or hydrogen generation require multielectronic transfers. To this aim, the project is
focused on Ru(II) dimers capable of reversibly storing up to four electrons when they are shined with visible light in acetonitrile in the presence
of sacrificial reductants.
The spectroelectrochemistry of these photocatalysts is carried out along with the analysis of their potential application to the photoreduction
of protons to molecular hydrogen.
Other complexes under study are rhenium carbonyls and macrocyclic and polynuclear complexes. The capability of these compounds as catalysts for
elimination of environmentally unfriendly species, e.g. CO2 or for the cleavage of ADN, is a subject looked upon by using electrochemical and
photoassisted techniques.
The group has developed and makes use of in situ optical methods and conventional techniques for electrochemical systems, namely, in the ultraviolet
visible, time resolved measurements with the aid of a multichannel analyzer and potential modulated reflectance methods. In the mid infrared, in
situ potential/intensity modulated reflectance techniques.
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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).
* “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).
* “The role of monomers and dimers in the reduction of ruthenium(ii) complexes of redox-active tetraazatetrapyridopentacene ligand”.
N.R. de Tacconi, R. Chitakunye, F.M. MacDonnell y R.O. Lezna
Journal of Physical Chemistry 112, 497-507 (2008).
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* “Electroreduction of the ruthenium complex [(bpy)2ru(tatpp)]Cl2 in water: insights on the mechanism of multielectron reduction and protonation of the tatpp acceptor ligand as a function of pH”.
N.R. de Tacconi, R.O. Lezna, R. Chitakunye y F.M. MacDonnell
Inorganic Chemistry 47 (19), 8847-8858 (2008).
* “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).
* “Spectroelectrochemistry of [(bpy)2ru(tatpp)]CCl2, a photocatalyst for hydrogen generation”.
R.O. Lezna, N.R. de Tacconi y F.M. MacDonnell
ECS Transactions 11 (23), 37-43 (2008).
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