Frustrated Lewis pairs oxidize H2 without metals

A carbon Lewis acid, BArF18, and lutidine cleave H2 and oxidize it at carbon electrodes about 1 V milder, without CO poisoning.

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What combination oxidizes H2 without precious metals?

Carbon Lewis acid 1+, BArF18, and lutidine as an electrochemical FLP.

How much does 1-H lower the oxidation potential?

An astonishing 1 V at ordinary carbon electrodes.

What energy does that 1 V represent, and vs prior FLPs?

About 197 kJ mol−1 and a further 110 mV improvement.

Is the system poisoned by CO?

No—it is highly CO-tolerant, unlike Pt or most hydrogenase mimics.

How fast is hydride transfer to 1+?

30% to 1-H in 25 min at 20 °C; quantitative in 17 h.

What role does the bridging borohydride play?

A redox-inactive hydride shuttle from the boron FLP to 1+.

Are H2-evolution side reactions a problem here?

No—unlike earlier electrochemical FLPs, incoming hydride does not make H2 with electrogenerated H+.

Can 1+ be turned over more than once?

Yes—electrocatalytic in 1+ and rechargeable multiple times without loss of activity (with enough base).

What Lewis pair activates H2 in the first place?

A frustrated Lewis pair of a bulky Lewis acid and base that can heterolytically cleave H2.

Did lutidine form a classical adduct with BArF18?

No adduct by NMR after 2 days in CD2Cl2.

What future FLP do the authors want?

A more air/moisture-stable boron FLP or a carbon acid that splits H2 without a boron shuttle.