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ELETTROCHIMICA MOLECOLARE |
Dipartimento di
Scienze Chimiche, Via Giorgieri, 1 - 34127 TRIESTE
Tel. ++39 0405583942
Dr. Claudio Tavagnacco
Dr. Silvia Peressini
ELECTROCHEMISTRY OF COORDINATION COMPOUNDS, ELECTROCATALYTIC ACTIVATION
OF MOLECULAR OXYGEN, COMPONENTS FOR FUEL CELLS DEVELOPMENT.
Investigation of redox
chemistry and catalytic properties of transition metal complexes (mainly metal
chelates as models of Vit.B12 group coenzymes of dioxygen transport
and dioxygen activation proteins). The reaction responsible for the biological
function is triggered by an electron transfer and is related to the redox
properties of the chelate metal center as tuned by the coordination sphere. The
research is aimed to the understanding of the mechanism of the biological
processes involving dioxygen transport or acivation, the identification of the
main structural or electronic factors influencing the catalytic pathways and
the efficiency of the catalyst. Electrocatalytic systems are being studied to
develop new methods for electrocatalytic oxidations of organic substrates in
mild conditions via electrocatalytic reduction of dioxygen. The research is
currently directed to the understanding of the role of the electrode surface
and of adsorption phenomena in the shift of the dioxygen one electron reduction
potential. This shift is accompanied by an easier production of superoxidic
species, enhancing the electrocatalytic formation of hydrogen peroxide or else
making easier the four electron reduction of dioxygen to water with full
exploitation of the free energy of dioxygen reduction in fuel cell technology.
More
recently our interest was involved also in protein electrochemistry, with
particularly interest to electron transfer redox enzymes, as cytochrome c, that
contains Fe ion in the prostetic group. Variation of electron transfer
thermodynamic parameters are studied on Au activated electrodes using
electrochemical techniques. The nature of the solvent, pH, ionic strenght, and
the presence of urea as denaturant, influence the E° values dependence vs T for
the Fe3+/Fe2+ redox couple. From this important
parameter, entropy and enthalpy variations can be calculated and relationed
with the change conformation and folding-unfolding of the protein in the various
experimental conditions.
A
significant time elapses before any new technological development is fully
exploited. Fuel cells were invented by W.Grove in 1839 and have taken longer
than most, despite the promise of clean and efficient power generator. There
are many different FC types, among the others our interest is towards the solid
oxide fuel cells (SOFCs) that are attracting much interest in the last years
for their ……
work in progress
Selection of recent publications:
- F.
Asaro, R.Dreos, G.Nardin, G.Pellizer, S.Peressini, L.Randaccio, P.Siega,
G.Tauzher, C. Tavagnacco, J.Organomet. Chem., 601, 114 (2000),
"Para-substituted diphenylborylated organocobaloximes: effects of
substituents on conformation and on redox properties."
- C.Tavagnacco,
"Laboratorio di Chimica", Libreria Goliardica Editrice S.r.L.,
Edizioni Goliardiche, 2000, Trieste.
- A. Bigotto, A. Felluga, R. Dreos, G. Nardin, L. Randaccio, G. Tauzher, S.
Peressini and C. Tavagnacco, J.Chem.Soc., Dalton Trans., 99-104, 2002,
"Organometallic Cobalt(III) Complexes with tridentate imino-oximic
ligands: structural, spectroscopic and electrochemical properties."
- S. Peressini, C.Tavagnacco, G. Costa and C. Amatore,
J.Electroanal.Chem., 532, 295-302 (2002),
"Electrochemical Reduction of Dioxygen into Hydrogen Peroxide in the
Presence of 4,6-Dimethyl-2-Thiopyrimidine in DMF"
- M.Borsari, M.Bellei, C. Tavagnacco, S. Peressini, D.Millo, G.Costa, Inorg.
Chim. Acta, 349, 182 (2003)
"Redox Thermodynamics Of Cytochrome C In Mixed Water-Organic Solvent Solutions"
- M. Borsari, M.Cannio, D.Dallari, C. Fontanesi, G. Gavioli,
S.Peressini and C. Tavagnacco, Australian Journal of chemistry, 56
1233-1238 (2003) "Substituent Effects in the Reduction Behaviour of Thio-
and Oxopyrimidines in Non-Aqueous Solvents"
-A. Melchior, S. Peressini, R. Portanova, C.
Sangregorio, C. Tavagnacco,* M. Tolazzi*. Inorg. Chim. Acta,
357/12, 3473-3482 (2004).
"Cobalt (II) and
Cadmium(II) Chelates with Nitrogen Donors and O2
Bonding to Co(II) Derivatives".
-R. Dreos, P. Siega, S. Scagliola, L.
Randaccio, G. Nardin, C.Tavagnacco, and M.Bevilacqua, Eur. J. Inorg. Chem., 3936-3944 (2005).
Synthesis, Characterization And Electrochemical
Properties Of Dinuclear Complexes
Assembled From Asymmetric Co(III) Bis(Dioximates) And Boronic Acids.
-M. Borsari, A. Ranieri, S. Bakari, M. Cannio, G. Gavioli, S. Peressini, C. Tavagnacco, Can. J. Chem./Rev. can. chim. 83(8): 1132-1136 (2005).
Role of the
Solvent in the Oxidative Process of a Hg electrode in the presence of thiopyrimidine derivatives.
M. Bevilacqua,
T. Montini, C. Tavagnacco, G. Vicario, P. Fornasiero, and M. Graziani, Solid State Ionics, (2006), Influence of synthesis route on morphology
and electrical properties of LaNi0.6Fe0.4O3.
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