A Binuclear Isocyanide Azadithiolatoiron Complex Relevant to the Active Site of Fe‐Only Hydrogenases: Synthesis, Structure and Electrochemical Properties

Abstract

An aromatic isocyanide-substituted diiron complex 5 has been synthesized as a mimic for the active site of Fe-only hydrogenases. Its structure has been fully characterized by X-ray crystallography. The 4-iodophenylisocyanide ligands in 5 are in the basal positions and are nearly parallel to each other, with π-π stacking interactions. Four isomeric geometries of complex 5 have been optimized by DFT calculations, and the electrochemical properties of 5 have been investi-

A new cumulene diiron complex related to the active site of Fe-only hydrogenases and its phosphine substituted derivatives: Synthesis, electrochemistry and structural characterization

“…The Fe\Fe bond distance is 2.5102(14) Å, and the average value for Fe\S bond lengths is 2.2396 Å. These values are in good agreement with those found for other all-CO diiron complexes [12][13][14][15][16][17][18][19][20][21][22][23]. A special feature for 1 is the rigid dithiolate bridge compared to pdt-or edt-bridged diiron complexes.…”

“…phosphines in most cases, would increase the electron density of the diiron center, thus facilitating the proton binding to the Fe(I)\Fe(I) active site. It is only quite recently that the importance of the organic part of dithiolates (S-to-S linker) in the model complexes has been recognized, as demonstrated by reports of a large number of model complexes with various S-to-S linkers, such as the alkyl bridges in [(μ-pdt)Fe 2 (CO) 6 ] and [(μ-edt)Fe 2 (CO) 6 ] (pdt = propane-1,3-dithiolato; edt = ethene-1,2-dithiolato) [12,13], N-substituted bridges like N-alkyl and N-benzyl species, and heterocyclic rings [14][15][16][17][18][19][20][21][22][23]. Among these models, the C-functionalized pdt mode is of particular interest, since it could be easily modified by functional transformation reactions to get a variety of biomimetic analogs with improved catalytic properties.…”

Diiron Proton Reduction Catalysts Possessing Electron‐Rich and Electron‐Poor Naphthalene‐1,8‐dithiolate Ligands

“…[Fe 2 (CO) 6 (SCH 2 XCH 2 S)] (X = CH 2 , [15][16][17][18] NR, [19][20][21][22][23][24][25][26][27][28][29][30][31][32] O, [20,33,34] and S; [35] R = alkyl or related species), as hydrogenase mimics that contain dithiolates with three-atom bridges. In addition, complexes with saturated and unsaturated two-atom bridges, such as [Fe 2 (CO) 6 -A C H T U N G T R E N N U N G (SCH 2 CH 2 S)] [18,[36][37][38][39][40][41][42][43] and [Fe 2 (CO) 6 (1,2-S 2 C 6 H 4 )], [44][45][46][47][48][49][50][51] have been synthesized.…”

Preparation and Protonation of Fe2(pdt)(CNR)6, Electron-Rich Analogues of Fe2(pdt)(CO)6

“…A similar effect had been observed in Fe 2 (pdt)(CO) 4 (CNC 6 H 4 -4-I) 2 . 15 Indicative of the stabilizing influence of this π -stacking, this (CNC 6 H 4 I) 2 species adopts an unusual cis-dibasal structure. In contrast, the isocyanide ligands are nonadjacent in Fe 2 (pdt)(CO) 4 (CNBu- t ) 2 , occupying the apical sites 14 as is typical for Fe 2 (pdt)(CO) 4 L 2 derivatives.…”