Table 1. Electrochemical and electrocatalytic data for complexes with increasing number of proton relays.

Compound	Fe(iii/ii) couple a (V) X = Cl	Fe(iii/ii) couple b (V) X = H	TOF c (s–1)	Overpotential d (V)
(CpC5F4N)Fe(depp)(X)	–0.45	–0.60	NC e	—
(CpC5F4N)Fe(PEtNMePEt)(X)	–0.41	–0.56	34	0.64
1-X	–0.42	–0.61	290	0.65

^aConditions: fluorobenzene solution, 1 mM [Fe], 0.1 M [ⁿBu₄N][B(C₆F₅)₄], 50 mV s^–1, 22 °C.

^bValues reported are for the oxidative peak potential.

^cReported values were determined upon addition of a DABCO solution, and are given under base- and scan rate-independent conditions (see above and the ESI† for additional information).

^dReported values were determined upon addition of a 10 : 1 DABCO to DABCO-H⁺ solution as the exogenous base, and are given under base- and scan rate-independent conditions (see above and the ESI† for additional information).

^eNot Catalytic (NC) – no significant current enhancement was observed, indicating this complex is not a catalyst for H₂ oxidation.