Reductive Activation of O22- from Vanadium(IV) Amidate Species
Date Issued
April 22, 2024
Abstract
The two electron reductive activation of O2 to O2
2-
is of particular interest to scientific
community mainly due to the use of peroxides as green oxidants and in powerful fuel-cells.
Among the metal-ions which activate O2, vanadium is of particular interest because of its
numerous oxidative catalytic properties. Reaction of either VIVOSO4
.3.5H2O or VIVOCl2 with N-
(8-quinolyl)pyridine-2-carboxamide (Hpbq) in CH3OH solution under atmospheric O2, at room
temperature, resulted in the quick formation of [VVO(k
2
-O2)(pbq)(H2O)](1). Compound 1
constitutes a rare example of formation of a (peroxo)oxidovanadium(V) complex from
molecular O2 and an oxidovanadium(IV) complex. The reaction of formation of compound 1vs.
time was monitored by 51V and 1H NMR, UV-vis, cw-X-EPR, Resonance Raman
spectroscopiesand cyclic voltammetry revealing the formation of a stable radical intermediate
[VVO(k
2
-O2)(pbq)(H2O)]•+
. Dynamic experiments in combination with computational
calculations were used to elucidate the mechanism of the reaction. The galvanic cell
{Zn|VIII,VII||cis-[VVO2(bpq)], [VVO(O2)(bpq)(H2O)],[VIVO(bpq)(H2O)2]
+
|O2|C(s)} was
manufactured, demonstrating that this technology can be used in Zn|H2O2 fuel cells generating
H2O2 in situ from atmospheric O2.
Acknowledgements: This work was co-funded by the European Regional Development Fund and the
2-
is of particular interest to scientific
community mainly due to the use of peroxides as green oxidants and in powerful fuel-cells.
Among the metal-ions which activate O2, vanadium is of particular interest because of its
numerous oxidative catalytic properties. Reaction of either VIVOSO4
.3.5H2O or VIVOCl2 with N-
(8-quinolyl)pyridine-2-carboxamide (Hpbq) in CH3OH solution under atmospheric O2, at room
temperature, resulted in the quick formation of [VVO(k
2
-O2)(pbq)(H2O)](1). Compound 1
constitutes a rare example of formation of a (peroxo)oxidovanadium(V) complex from
molecular O2 and an oxidovanadium(IV) complex. The reaction of formation of compound 1vs.
time was monitored by 51V and 1H NMR, UV-vis, cw-X-EPR, Resonance Raman
spectroscopiesand cyclic voltammetry revealing the formation of a stable radical intermediate
[VVO(k
2
-O2)(pbq)(H2O)]•+
. Dynamic experiments in combination with computational
calculations were used to elucidate the mechanism of the reaction. The galvanic cell
{Zn|VIII,VII||cis-[VVO2(bpq)], [VVO(O2)(bpq)(H2O)],[VIVO(bpq)(H2O)2]
+
|O2|C(s)} was
manufactured, demonstrating that this technology can be used in Zn|H2O2 fuel cells generating
H2O2 in situ from atmospheric O2.
Acknowledgements: This work was co-funded by the European Regional Development Fund and the