Diiron Dichalcogenolato (Se and Te) Complexes: Models for the Active Site of [FeFe] Hydrogenase

Abstract

Keywords: Iron / Selenium / Tellurium / Hydrogenases / Electrocatalysis A short overview of diiron dichalcogenolato (Se and Te) model complexes related to the chemistry of the diiron subsite of [FeFe] hydrogenase is presented. These model complexes allow direct comparison with the diiron dithiolato compound analogues for their ability to catalyze the formation of H 2 from weak acids. Few detailed photoelectron spec-

Effects of Alkane Linker Length and Chalcogen Character in [FeFe]‐Hydrogenase Inspired Compounds

“…This shift to lower ν‐CO suggests that there is more electron density being donated into the π‐backbonding orbitals of the COs for the Se‐containing compounds. The shift to lower ν‐CO upon switching from S to Se is expected and the calculated Voronoi deformation electron density distributions, which is less sensitive to basis set artifacts than other population analyses, agrees with the observed frequency shifts. Much of the change around the diiron core is transferred to the carbonyls, but an increase in electron density around Fe is observed from the S compound to the analogous Se compound by 0.16 e − .…”

“…Recently, Se homologues of [FeFe]‐hydrogenase active site models with the [2Fe2Se] subunit were reported . Enhancement of the catalytic activity toward proton reduction was observed with strong acid ( p ‐toluenesulfonic acid in CH 3 CN) upon replacement of S atoms by more electropositive Se atoms . Substitution of Se into the butterfly core does not, however, guarantee an improved catalytic activity when weak acid (acetic acid in CH 3 CN) was used.…”

[FeFe]-Hydrogenases: recent developments and future perspectives

“…due to an increase of electron density at the diiron site and optimized electron transfer, accordingly. 41,[44][45][46] Maturation with the synthetic adSe cluster was performed 47 and yielded the selenium-modified HydA1 and CpI variants. The modified hydrogenases revealed a slightly increased H 2 release activity as compared to the wildtype enzyme.…”

[N,N′-Bis(2,6-diisopropylphenyl)acenaphthene-1,2-diimine-1κ2N,N′]heptacarbonyl-1κC,2κ3C,3κ3C-di-μ3-tellurido-triiiron(II)(2Fe—Fe)

“…Iron chalcogenide carbonyl clusters (ICCCs) attract a great deal of interest because of their similarity to the active subsites of [FeFe]-hydrogenase and related biological systems (Groysman & Holm, 2009;Tard & Pickett, 2009;Harb et al, 2011;Song, Gai et al, 2009). Recently, interest in ICCCs has increased due to the demonstration of catalytic activity in some complexes based on the {Fe 2 S 2 (CO) 6 } group towards photoreduction of H + to H 2 (Song et al, 2007(Song et al, , 2010Song, Yan et al, 2009;Gao et al, 2007).…”