Ligand Adducts of Bis(acetylacetonato)iron(II): A 1H NMR Study

Ligand Adducts of Bis(acetylacetonato)iron(II): A 1H NMR Study

by Zhigang Xue, Jean-Claude Daran, Yohan Champouret and Rinaldo Poli

Inorganic Chemistry DOI: 10.1021/ic201486v

Mechanistic Studies of O2 Reduction Effected by Group 9 Bimetallic Hydride Complexes

Mechanistic Studies of O2 Reduction Effected by Group 9 Bimetallic Hydride Complexes:

Journal of the American Chemical Society DOI: 10.1021/ja2069196

Nocera and Teets

Liquid-phase catalytic transfer hydrogenation and cyclization of levulinic acid and its esters to [gamma]-valerolactone over metal oxide catalysts

Liquid-phase catalytic transfer hydrogenation and cyclization of levulinic acid and its esters to [gamma]-valerolactone over metal oxide catalysts:

Chem. Commun., 2011, Advance Article DOI: 10.1039/C1CC14748J, Communication

Mei Chia, James A. Dumesic
The reduction of levulinic acid and its esters to [gamma]-valerolactone can be achieved via the Meerwein-Ponndorf-Verley reaction over inexpensive and regenerable metal oxide catalysts.

A rare terminal dinitrogen complex of chromium

A rare terminal dinitrogen complex of chromium:

Chem. Commun., 2011, Advance Article
DOI: 10.1039/C1CC15430C, Communication

Michael T. Mock, Shentan Chen, Roger Rousseau, Molly J. O'Hagan, William G. Dougherty, W. Scott Kassel, Daniel L. DuBois, R. Morris Bullock
A rare example of a terminal bis(dinitrogen) complex of chromium(0) was prepared, supported by P^Ph₂N^Bn₂, a diphosphine ligand with positioned pendant amines.
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Specific Incorporation of Chalcogenide Bridge Atoms in Molybdenum/Tungsten-Iron-Sulfur Single Cubane Clusters

Specific Incorporation of Chalcogenide Bridge Atoms in Molybdenum/Tungsten-Iron-Sulfur Single Cubane Clusters:

by Amit Majumdar and R. H. Holm

Inorganic Chemistry DOI: 10.1021/ic2018117

Note the use of (CH2NMe)3 as a labile tridentate

Approaches to efficient molecular catalyst systems for photochemical H2 production using [FeFe]-hydrogenase active site mimics

Approaches to efficient molecular catalyst systems for photochemical H2 production using [FeFe]-hydrogenase active site mimics:

Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT11166C, Perspective

Mei Wang, Lin Chen, Xueqiang Li, Licheng Sun
This perspective reports on progress achieved in the past three years in the field of photochemical H₂ production using [FeFe]-H₂ase mimics as catalysts.
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A Reduced (β-Diketiminato)iron Complex with End-On and Side-On Nitriles: Strong Backbonding or Ligand Non-Innocence?

A Reduced (β-Diketiminato)iron Complex with End-On and Side-On Nitriles: Strong Backbonding or Ligand Non-Innocence?:

Abstract

Treatment of the iron(I) synthon L^MeFeNNFeL^Me (L^Me = β-diketiminato ligand) with pivalonitrile gives a formally iron(I) complex L^MeFe(NCtBu)₂, which has one strongly bound side-on nitrile and one weakly bound end-on nitrile ligand. The side-on nitrile ligand has N–C–C bending and N–C weakening that suggests partial reduction of the nitrile group. The S = 3/2 ground state of this molecule can be described as either an iron(II) atom with a nitrile radical anion or an iron(I) atom that is strongly backbonding. DFT computations show that strong backbonding comes from a doubly occupied orbital, and that there is little ligand radical character. Therefore, the iron(I) formulation is the most appropriate. This study exemplifies how one-electron transfer to ligands and two-electron backbonding to ligands may be distinguished by using spectroscopically calibrated and validated computations.

In the S = 3/2 molecule L^MeFe(NCtBu)₂, the side-on nitrile ligand has N–C–C bending and N–C weakening that suggests partial reduction of the nitrile group. Even though the molecule has three unpaired spins, the interaction between the iron atom and the nitrile ligand is two-electron backbonding rather than redox non-innocence.

Synthesis, Structures, and Transfer Hydrogenation Catalysis of Bifunctional Iridium Complexes Bearing a C–N Chelate Oxime Ligand

Synthesis, Structures, and Transfer Hydrogenation Catalysis of Bifunctional Iridium Complexes Bearing a C–N Chelate Oxime Ligand:

Abstract

We have synthesized a series of organometallic oxime complexes as novel metal–ligand cooperating bifunctional catalysts. The reaction of [{Cp*IrCl(μ₂-Cl)}₂] with ketoximes in the presence of sodium acetate afforded the half-sandwich chlorido iridium complexes 6 bearing a C–N chelate oxime ligand with a protic OH group in the β-position to the metal. Complex 6a, derived from acetophenone oxime, reacted with silver triflate to give the triflate complex 7 and cationic nitrile complex 8 depending upon the reaction solvent. Complexes 6 also reacted with a base in dichloromethane to afford the oximato-bridged dinuclear complexes 9, which were converted back to the chlorido complexes 6 upon treatment with an amine hydrochloride. In contrast, dehydrochlorination of 6 in 2-propanol as well as the reaction of 9 with 2-propanol yielded the hydrido-bridged dinuclear oxime–oximato complexes 10. Crossover experiments revealed that 10 dissociates into the mononuclear hydrido–oxime complex 11 and unsaturated oximato complex 12, which are interconvertible by reactions with hydrogen donors and acceptors. Owing to the metal–ligand cooperation, 10 effectively catalyzed transfer hydrogenation of ketones with 2-propanol.

A series of organometallic oxime complexes featuring a β-protic OH group have been synthesized. The hydrido-bridgedoxime–oximato complex (pictured) dissociates into two mononuclear species, which are interconvertible through reactions with hydrogen donors and acceptors. Owing to the metal–ligand cooperation, catalytic transfer hydrogenation of ketones with 2-propanol has been achieved.

Visible-Light-Driven H2 Generation from Water and CO2 Conversion by Using a Zwitterionic Cyclometalated Iridium(III) Complex

Visible-Light-Driven H2 Generation from Water and CO2 Conversion by Using a Zwitterionic Cyclometalated Iridium(III) Complex:

From light comes hydrogen: Photosensitizer [Ir(4-CF₃bt)₂(Hbpdc)] behaves as a very active promoter towards H₂ evolution from water when irradiated with visible light (see figure). A remarkable selective-photoreduction for CO₂ was also achieved.

57Fe ENDOR Spectroscopy and ‘Electron Inventory’ Analysis of the Nitrogenase E4 Intermediate Suggest the Metal-Ion Core of FeMo-Cofactor Cycles Through Only One Redox Couple

57Fe ENDOR Spectroscopy and ‘Electron Inventory’ Analysis of the Nitrogenase E4 Intermediate Suggest the Metal-Ion Core of FeMo-Cofactor Cycles Through Only One Redox Couple:

Journal of the American Chemical SocietyDOI: 10.1021/ja205304t

Synthesis and Decarbonylation Reactions of the Triiron Phosphinidene Complex [Fe3Cp3(μ-H)(μ3-PPh)(CO)4]: Easy Cleavage and Formation of P–H and Fe–Fe Bonds

Synthesis and Decarbonylation Reactions of the Triiron Phosphinidene Complex [Fe3Cp3(μ-H)(μ3-PPh)(CO)4]: Easy Cleavage and Formation of P–H and Fe–Fe Bonds:

Inorganic Chemistry DOI: 10.1021/ic201491v

Impact of Ligand Exchange in Hydrogen Production from Cobaloxime-Containing Photocatalytic Systems

Impact of Ligand Exchange in Hydrogen Production from Cobaloxime-Containing Photocatalytic Systems:

Inorganic Chemistry DOI: 10.1021/ic2010166

Photosensitized Water Oxidation by Use of a Bioinspired Manganese Catalyst

Photosensitized Water Oxidation by Use of a Bioinspired Manganese Catalyst:

Manganificent potential: A dinuclear manganese catalyst contains metal centers that are coordinated by a central phenolate, with adjoining imidazole and carboxylate groups, which are all important functionalities in the natural oxygen-evolving center. The complex catalyzes the conversion of water to oxygen in the presence of a single-electron oxidant [Ru(bpy)₃]³⁺ (see picture, bpy=2,2′-bipyridine, A=acceptor).

Oxygen-Tolerant [NiFe]-Hydrogenases: The Individual and Collective Importance of Supernumerary Cysteines at the Proximal Fe-S Cluster

Oxygen-Tolerant [NiFe]-Hydrogenases: The Individual and Collective Importance of Supernumerary Cysteines at the Proximal Fe-S Cluster:

Journal of the American Chemical Society

DOI: 10.1021/ja205393w

Artificial metalloenzymes for olefin metathesis based on the biotin-(strept)avidin technology

Artificial metalloenzymes for olefin metathesis based on the biotin-(strept)avidin technology:

Chem. Commun., 2011, Advance Article DOI: 10.1039/C1CC15004A, Communication

Cheikh Lo, Mark R. Ringenberg, David Gnandt, Yvonne Wilson, Thomas R. Ward
Incorporation of a biotinylated Hoveyda-Grubbs catalyst within (strept)avidin affords artificial metalloenzymes for the ring-closing metathesis of N-tosyl diallylamine in aqueous solution. Optimization of the performance can be achieved either by chemical or genetic means.

Catalytic Turnover of [FeFe]-Hydrogenase Based on Single-Molecule Imaging

Catalytic Turnover of [FeFe]-Hydrogenase Based on Single-Molecule Imaging:

Journal of the American Chemical Society

DOI: 10.1021/ja207461t

A Nonclassical Dihydrogen Adduct of S = 1/2 Fe(I)

A Nonclassical Dihydrogen Adduct of S = 1/2 Fe(I):

Journal of the American Chemical Society

DOI: 10.1021/ja207003m

Wilkinson's iridium acetate trimer as a water-oxidation catalyst

Wilkinson's iridium acetate trimer as a water-oxidation catalyst:

Chem. Commun., 2011, Advance Article
DOI: 10.1039/C1CC15501F, Communication

Alexander R. Parent, James D. Blakemore, Gary W. Brudvig, Robert H. Crabtree
Wilkinson's iridium acetate trimer is a competent precatalyst for water oxidation with NaIO₄ but rapidly decomposes using Ce(IV) as a primary oxidant.
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Structural and Electronic Study of an Amorphous MoS3 Hydrogen-Generation Catalyst on a Quantum-Controlled Photosensitizer

Structural and Electronic Study of an Amorphous MoS3 Hydrogen-Generation Catalyst on a Quantum-Controlled Photosensitizer:

Light–water reactor: An amorphous molybdenum sulfide species structurally similar to reduced MoS₃ is shown to be photocatalytically active for hydrogen generation from H₂O with visible light (see picture; TEOA=triethanolamine). Thermally deposited in one step, MoS₃ is photosensitized by quantum-controlled semiconductor nanocrystals that serve as model systems for the photophysics of solar fuel generation.

Synthesis and Structural Characterization of Tris(2-mercapto-1-adamantylimidazolyl)hydroborato Complexes: A Sterically Demanding Tripodal [S3] Donor Ligand

Synthesis and Structural Characterization of Tris(2-mercapto-1-adamantylimidazolyl)hydroborato Complexes: A Sterically Demanding Tripodal [S3] Donor Ligand:

Inorganic Chemistry

DOI: 10.1021/ic201504d