A new nitrogen heterocyclic carbene containing diiron complex as bio-inspired catalyst for proton reduction and benzen

摘要

A new diiron complex (mu-dmedt)[Fe-2(Co)(5)IPr] (2, dmedt = 2,3-butanedithiol, IPr = 1,3-bis(2,6-diisopropylphenyl) imidazol-2-ylidene) was synthesized as analogue of the active site of [Fe-Fe]H(2)ases. The sterically bulky nitrogen heterocyclic carbene ligand of IPr coordinated to the iron center was introduced via CO/L substitution reaction in mild conditions. The reactivity of electrocatalytic reduction of proton and catalytic hydroxylation of benzene were explored for the developed diiron complex. Complex 2 undergoes two irreversible reduction events at ca. -2.17 V and -2.50 V and acts as an efficient electrocatalyst for proton reduction to hydrogen with both HOAc and H2O as proton source. The catalytic hydroxylation of benzene by complex 2 achieved phenol yield of 32.4% with almost 100% selectivity. The enhanced catalytic activity compared to the all carbonyl precursor and related derivatives was attributed to the good electron donating ability of introduced IPr ligand. (C) 2016 Elsevier B.V. All rights reserved.