A mono-oxo-bridged binuclear iron(iii) complex with a Fe–O–Fe angle of 180.0° and its catalytic activity for hydrogen evolution†
Abstract
There are potential applications for binuclear oxo-bridged iron complexes in biological processes, catalysts, and magnetic materials, and the design of new bridged-iron complexes is important. A new mono-oxo-bridged binuclear iron(III) complex, [(H2O)(bpc)Fe–O–Fe(bpc)(H2O)], is designed and provided by the reaction of FeCl3 with 1,2-bis(pyridine-2-carboxamido)-4,5-dichlorobenzene) (H2bpc) in our group. Structural investigations show that two ions are connected with a Fe–O–Fe angle of 180.0°, so it is a novel linear mono-oxo-bridged iron complex. Magnetic studies indicate that the iron(III) ions are in low spin (ls) states. Electrochemical investigations exhibit that [(H2O)(bpc)Fe–O–Fe(bpc)(H2O)] has FeIV/III, FeIII/II, and FeII/I couples at 0.689, −0.476, and −2.065 V versus Ag/AgNO3, respectively, and can electro-catalyze hydrogen evolution from acetic acid with a rate constant of 7561.95 M−1 s−1.