Search

[FeFe] hydrogenases demonstrate remarkable catalytic efficiency in hydrogen evolution and oxidation processes. However, susceptibility of these enzymes to oxygen‐induced degradation impedes their practical deployment in hydrogen‐production devices and fuel cells. Recent investigations into the oxygen‐stable (Hinact) state of the H‐cluster revealed its inherent capacity to resist oxygen degradation. Herein, we present findings on Cl‐ and SH‐bound [2Fe‐2S] complexes, bearing relevance to the oxygen‐stable state within a biological context. A characteristic attribute of these complexes is the terminal Cl−/SH− ligation to the iron center bearing the CO bridge. Structural analysis of the t‐Cl demonstrates a striking resemblance to the Hinact state of DdHydAB and CbA5H. The t‐Cl/t‐SH exhibit reversible oxidation, with both redox species, electronically, being the first biomimetic analogs to the Htrans and Hinact states. These complexes exhibit notable resistance against oxygen‐induced decomposition, supporting the potential oxygen‐resistant nature of the Htrans and Hinact states. The swift reductive release of the Cl‐/SH‐group demonstrates its labile and kinetically controlled binding. The findings garnered from these investigations offer valuable insights into properties of the enzymatic O2‐stable state, and key factors governing deactivation and reactivation conversion. This work contributes to the advancement of bio‐inspired molecular catalysts and the integration of enzymes and artificial catalysts into H2‐evolution devices and fuel‐cell applications. [ABSTRACT FROM AUTHOR]

The oxygen‐stable state of the [Fe,Fe] hydrogenase H‐cluster is modeled. Insights into properties of the enzymatic oxygen‐stable state, and key factors governing deactivation and reactivation mechanism are elucidated. For details see the Research Article (e202408142) by Yih‐Chern Horng, Ming‐Hsi Chiang et al...By Yu‐Chiao Liu; Kai‐Ti Chu; Hong‐Ru Wang; Gene‐Hsiang Lee; Mei‐Chun Tseng; Cheng‐Hsin Wang; Yih‐Chern Horng and Ming‐Hsi ChiangReported by Author; Author; Author; Author; Author; Author; Author; Author [Extracted from the article]

The first structurally characterized copper cluster with a Cu13 centered cuboctahedral arrangement, a model of the bulk copper fcc structure, was observed in [Cu13(S2CN nBu2)6(C≡CR)4](PF6) (R=C(O)OMe, C6H4F) nanoclusters. Four of the eight triangular faces of the cuboctahedron are capped by acetylide groups in μ3 fashion, and each of the six square faces is bridged by a dithiolate ligand in μ2,μ2 fashion, which leads to a truncated tetrahedron of twelve sulfur atoms. DFT calculations are fully consistent with the description of these Cu13 clusters as two-electron superatoms, that is, a [Cu13]11+ core passivated by ten monoanionic ligands, with an a1 HOMO containing two 1S jellium electrons. [ABSTRACT FROM AUTHOR]

A polyhydrido copper nanocluster, [Cu20H11{Se2P(O iPr)2}9] ( 2H), which exhibits an intrinsically chiral inorganic core of C3 symmetry, was synthesized from achiral [Cu20H11{S2P(O iPr)2}9] ( 1H) of C3 h symmetry by a ligand-exchange method. The structure has a distorted cuboctahedral Cu13 core, two triangular faces of which are capped along the C3 axis, one by a Cu6 cupola and the other by a single Cu atom. The Cu20 framework is further stabilized by 9 diselenophosphate and 11 hydride ligands. The number of hydride, phosphorus, and selenium resonances and their splitting patterns in multinuclear NMR spectra of 2H indicate that the chiral Cu20H11 core retains its C3 symmetry in solution. The 11 hydride ligands were located by neutron diffraction experiments and shown to be capping μ3-H and interstitial μ5-H ligands (in square-pyramidal and trigonal-bipyramidal cavities), as supported by DFT calculations on [Cu20H11(Se2PH2)9] ( 2H′) as a simplified model. [ABSTRACT FROM AUTHOR]

A novel discrete [Ag21{S2P(O iPr)2}12](PF6) nanocluster has been synthesized and characterized by single-crystal X-ray diffraction and also NMR spectroscopy (1H, 31P), ESI mass spectrometry, and other analytic techniques (XPS, EDS, UV/Vis spectroscopy). The Ag21 skeleton has an unprecedented silver-centered icosahedron that is capped by eight additional metal atoms. The whole framework is protected by twelve dithiophosphate ligands. According to the spherical Jellium model, the stability of monocationic nanocluster can be described by an 8-electron superatom with 1S2 1P6 configuration, as confirmed by DFT calculations. [ABSTRACT FROM AUTHOR]