2 research outputs found
Rhenium Complexes Based on 2āPyridyl-1,2,3-triazole Ligands: A New Class of CO<sub>2</sub> Reduction Catalysts
A series of [ReĀ(N^N)Ā(CO)<sub>3</sub>(X)] (N^N = diimine and X = halide) complexes based on 4-(2-pyridyl)-1,2,3-triazole
(pyta) and 1-(2-pyridyl)-1,2,3-triazole (tapy) diimine ligands have
been prepared and electrochemically characterized. The first ligand-based
reduction process is shown to be highly sensitive to the nature of
the isomer as well as to the substituents on the pyridyl ring, with
the peak potential changing by up to 700 mV. The abilities of this
class of complexes to catalyze the electroreduction and photoreduction
of CO<sub>2</sub> were assessed for the first time. It is found that
only Re pyta complexes that have a first reduction wave with a peak
potential at ca. ā1.7 V vs SCE are active, producing CO as
the major product, together with small amounts of H<sub>2</sub> and
formic acid. The catalytic wave that is observed in the CVs is enhanced
by the addition of water or trifluoroethanol as a proton source. Long-term
controlled potential electrolysis experiments gave total Faradaic
yield close to 100%. In particular, functionalization of the triazolyl
ring with a 2,4,6-tri-<i>tert</i>-butylphenyl group provided
the catalyst with a remarkable stability
Rhenium Complexes Based on 2āPyridyl-1,2,3-triazole Ligands: A New Class of CO<sub>2</sub> Reduction Catalysts
A series of [ReĀ(N^N)Ā(CO)<sub>3</sub>(X)] (N^N = diimine and X = halide) complexes based on 4-(2-pyridyl)-1,2,3-triazole
(pyta) and 1-(2-pyridyl)-1,2,3-triazole (tapy) diimine ligands have
been prepared and electrochemically characterized. The first ligand-based
reduction process is shown to be highly sensitive to the nature of
the isomer as well as to the substituents on the pyridyl ring, with
the peak potential changing by up to 700 mV. The abilities of this
class of complexes to catalyze the electroreduction and photoreduction
of CO<sub>2</sub> were assessed for the first time. It is found that
only Re pyta complexes that have a first reduction wave with a peak
potential at ca. ā1.7 V vs SCE are active, producing CO as
the major product, together with small amounts of H<sub>2</sub> and
formic acid. The catalytic wave that is observed in the CVs is enhanced
by the addition of water or trifluoroethanol as a proton source. Long-term
controlled potential electrolysis experiments gave total Faradaic
yield close to 100%. In particular, functionalization of the triazolyl
ring with a 2,4,6-tri-<i>tert</i>-butylphenyl group provided
the catalyst with a remarkable stability