Abstract
Oxidation of hydrogen (H2) to protons and electrons for energy production in fuel cells is currently catalyzed by platinum, but its low abundance and high cost present drawbacks to widespread adoption. Precisely controlled proton removal from the active site is critical in hydrogenase enzymes in nature that catalyze H2 oxidation using earth-abundant metals (iron and nickel). Here we report a synthetic iron complex, (CpC5F4N)Fe(PEtN(CH2)3NMe2PEt)(Cl), that serves as a precatalyst for the oxidation of H2, with turnover frequencies of 290 s-1 in fluorobenzene, under 1 atm of H2 using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the exogenous base. The inclusion of a properly tuned outer coordination sphere proton relay results in a cooperative effect between the primary, secondary and outer coordination spheres for moving protons, increasing the rate of H2 oxidation without increasing the overpotential when compared with the analogous complex featuring a single pendant base. This finding emphasizes the key role of pendant amines in mimicking the functionality of the proton pathway in the hydrogenase enzymes.
| Original language | English |
|---|---|
| Pages (from-to) | 2737-2745 |
| Number of pages | 9 |
| Journal | Chemical Science |
| Volume | 6 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - May 1 2015 |
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ASJC Scopus subject areas
- Chemistry(all)
Cite this
Increasing the rate of hydrogen oxidation without increasing the overpotential : A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay. / Darmon, Jonathan M.; Kumar, Neeraj; Hulley, Elliott B.; Weiss, Charles J.; Raugei, Simone; Bullock, R Morris; Helm, Monte.
In: Chemical Science, Vol. 6, No. 5, 01.05.2015, p. 2737-2745.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Increasing the rate of hydrogen oxidation without increasing the overpotential
T2 - A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay
AU - Darmon, Jonathan M.
AU - Kumar, Neeraj
AU - Hulley, Elliott B.
AU - Weiss, Charles J.
AU - Raugei, Simone
AU - Bullock, R Morris
AU - Helm, Monte
PY - 2015/5/1
Y1 - 2015/5/1
N2 - Oxidation of hydrogen (H2) to protons and electrons for energy production in fuel cells is currently catalyzed by platinum, but its low abundance and high cost present drawbacks to widespread adoption. Precisely controlled proton removal from the active site is critical in hydrogenase enzymes in nature that catalyze H2 oxidation using earth-abundant metals (iron and nickel). Here we report a synthetic iron complex, (CpC5F4N)Fe(PEtN(CH2)3NMe2PEt)(Cl), that serves as a precatalyst for the oxidation of H2, with turnover frequencies of 290 s-1 in fluorobenzene, under 1 atm of H2 using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the exogenous base. The inclusion of a properly tuned outer coordination sphere proton relay results in a cooperative effect between the primary, secondary and outer coordination spheres for moving protons, increasing the rate of H2 oxidation without increasing the overpotential when compared with the analogous complex featuring a single pendant base. This finding emphasizes the key role of pendant amines in mimicking the functionality of the proton pathway in the hydrogenase enzymes.
AB - Oxidation of hydrogen (H2) to protons and electrons for energy production in fuel cells is currently catalyzed by platinum, but its low abundance and high cost present drawbacks to widespread adoption. Precisely controlled proton removal from the active site is critical in hydrogenase enzymes in nature that catalyze H2 oxidation using earth-abundant metals (iron and nickel). Here we report a synthetic iron complex, (CpC5F4N)Fe(PEtN(CH2)3NMe2PEt)(Cl), that serves as a precatalyst for the oxidation of H2, with turnover frequencies of 290 s-1 in fluorobenzene, under 1 atm of H2 using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the exogenous base. The inclusion of a properly tuned outer coordination sphere proton relay results in a cooperative effect between the primary, secondary and outer coordination spheres for moving protons, increasing the rate of H2 oxidation without increasing the overpotential when compared with the analogous complex featuring a single pendant base. This finding emphasizes the key role of pendant amines in mimicking the functionality of the proton pathway in the hydrogenase enzymes.
UR - http://www.scopus.com/inward/record.url?scp=84928562467&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84928562467&partnerID=8YFLogxK
U2 - 10.1039/c5sc00398a
DO - 10.1039/c5sc00398a
M3 - Article
AN - SCOPUS:84928562467
VL - 6
SP - 2737
EP - 2745
JO - Chemical Science
JF - Chemical Science
SN - 2041-6520
IS - 5
ER -