First insights into the protonation of dissymetrically disubstituted di-iron azadithiolate models of the [FeFe]H2ases active site

Abstract

Dissymetrically disubstituted di-iron azadithiolate complexes [Fe2(CO)4(kappa 2-LL){mu-SCH2N(iPr)CH2S}] (LL = dppe, phen) protonate exclusively at the N atom of the bridge, like the hexacarbonyl precursor but in contrast to symmetrically disubstituted analogues; substitution of dppe for two CO groups noticeably increases the kinetics of the electrocatalytic proton reduction process.

Electrochemical study of the role of a H-bridged, unsymmetrically disubstituted diiron complex in proton reduction catalysis

“…0.2 and 0.3 V, respectively [8,48]. For these complexes, as well as for the hexacarbonyl parent of 1, namely [Fe 2 (CO) 6 (l-pdt)] [4], and for a phosphido-bridged analogue [Fe 2 (CO) 6 (l-(Ph)P(CH 2 ) 3 P(Ph)] [6b], the second process started to develop only when the current of the first one levelled off.…”

Modeling [FeFe] hydrogenase: Synthesis and protonation of a diiron dithiolate complex containing a phosphine-N-heterocyclic-carbene ligand

“…6). Closer inspection of the CV reveals however that the catalytic wave is composed of several peaks depending on the acid concentration, which suggests that several mechanisms might be involved [22].…”

Investigation of amino acid containing [FeFe] hydrogenase models concerning pendant base effects

“…In every case only a nonsoluble dark brown precipitate was obtained, suggesting decomposition of the product. One possible explanation for the decomposition is the presence of the free amino group, as the amino-function itself is able to coordinate to iron [33,34] and may form an instable assembly under these conditions. Accordingly, the ligand was protected (2) using di-tert-butyl dicarbonate [(Boc) 2 O] (Scheme 1) [35].…”