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Metal-free dihydrogen oxidation by a borenium cation: a combined electrochemical/frustrated Lewis pair approach.

Lawrence EJ, Herrington TJ, Ashley AE, Wildgoose GG - Angew. Chem. Int. Ed. Engl. (2014)

Bottom Line: Herein, we report a metal-free approach to catalyze the oxidation of H2 by combining the ability of frustrated Lewis pairs (FLPs) to heterolytically cleave H2 with the in situ electrochemical oxidation of the resulting borohydride.The use of the NHC-stabilized borenium cation [(IiPr2)(BC8H14)](+) (IiPr2=C3H2(NiPr)2, NHC=N-heterocyclic carbene) as the Lewis acidic component of the FLP is shown to decrease the voltage required for H2 oxidation by 910 mV at inexpensive carbon electrodes, a significant energy saving equivalent to 175.6 kJ mol(-1).The NHC-borenium Lewis acid also offers improved catalyst recyclability and chemical stability compared to B(C6F5)3, the paradigm Lewis acid originally used to pioneer our combined electrochemical/frustrated Lewis pair approach.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ (UK) http://wildgooseresearch.com.

No MeSH data available.


a) Simulated (circles) and experimental (line) cyclic voltammograms showing the full potential window for 1-H (2.0 mm, CH2Cl2) at a voltage scan rate (ν) of 500 mV s−1. Comparisons between experimental and simulated data showing the quality of fitting for: b) the oxidative peak potential (Ep, ox) versus the logarithm of voltage scan rate (v), and c) the oxidative peak current (ip,ox) versus the square root of voltage scan rate (v).
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f2: a) Simulated (circles) and experimental (line) cyclic voltammograms showing the full potential window for 1-H (2.0 mm, CH2Cl2) at a voltage scan rate (ν) of 500 mV s−1. Comparisons between experimental and simulated data showing the quality of fitting for: b) the oxidative peak potential (Ep, ox) versus the logarithm of voltage scan rate (v), and c) the oxidative peak current (ip,ox) versus the square root of voltage scan rate (v).

Mentions: Digital simulation of the cyclic voltammetric data for the oxidation of 1-H was undertaken in order to extract pertinent mechanistic, thermodynamic, and kinetic parameters (see the Supporting Information for further details). The experimental and simulated cyclic voltammograms were in very good agreement (Figure 2) when the simulation was performed in accordance with the mechanism proposed in Scheme 2.


Metal-free dihydrogen oxidation by a borenium cation: a combined electrochemical/frustrated Lewis pair approach.

Lawrence EJ, Herrington TJ, Ashley AE, Wildgoose GG - Angew. Chem. Int. Ed. Engl. (2014)

a) Simulated (circles) and experimental (line) cyclic voltammograms showing the full potential window for 1-H (2.0 mm, CH2Cl2) at a voltage scan rate (ν) of 500 mV s−1. Comparisons between experimental and simulated data showing the quality of fitting for: b) the oxidative peak potential (Ep, ox) versus the logarithm of voltage scan rate (v), and c) the oxidative peak current (ip,ox) versus the square root of voltage scan rate (v).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4257500&req=5

f2: a) Simulated (circles) and experimental (line) cyclic voltammograms showing the full potential window for 1-H (2.0 mm, CH2Cl2) at a voltage scan rate (ν) of 500 mV s−1. Comparisons between experimental and simulated data showing the quality of fitting for: b) the oxidative peak potential (Ep, ox) versus the logarithm of voltage scan rate (v), and c) the oxidative peak current (ip,ox) versus the square root of voltage scan rate (v).
Mentions: Digital simulation of the cyclic voltammetric data for the oxidation of 1-H was undertaken in order to extract pertinent mechanistic, thermodynamic, and kinetic parameters (see the Supporting Information for further details). The experimental and simulated cyclic voltammograms were in very good agreement (Figure 2) when the simulation was performed in accordance with the mechanism proposed in Scheme 2.

Bottom Line: Herein, we report a metal-free approach to catalyze the oxidation of H2 by combining the ability of frustrated Lewis pairs (FLPs) to heterolytically cleave H2 with the in situ electrochemical oxidation of the resulting borohydride.The use of the NHC-stabilized borenium cation [(IiPr2)(BC8H14)](+) (IiPr2=C3H2(NiPr)2, NHC=N-heterocyclic carbene) as the Lewis acidic component of the FLP is shown to decrease the voltage required for H2 oxidation by 910 mV at inexpensive carbon electrodes, a significant energy saving equivalent to 175.6 kJ mol(-1).The NHC-borenium Lewis acid also offers improved catalyst recyclability and chemical stability compared to B(C6F5)3, the paradigm Lewis acid originally used to pioneer our combined electrochemical/frustrated Lewis pair approach.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ (UK) http://wildgooseresearch.com.

No MeSH data available.