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

Theoretical Analysis of Mechanistic Pathways for Hydrogen Evolution Catalyzed by Cobaloximes

Theoretical Analysis of Mechanistic Pathways for Hydrogen Evolution Catalyzed by Cobaloximes:

Inorganic Chemistry

DOI: 10.1021/ic201842v

Organochromium Complexes Bearing Noninnocent Diimine Ligands

Organochromium Complexes Bearing Noninnocent Diimine Ligands:

Abstract

We have prepared several anionic and neutral organochromium complexes featuring noninnocent α-diimine ligands. All neutral and anionic complexes refrain from insertion of the C=N bonds of the diimine ligand into the chromium–carbon bonds, presumably due to the reduced nature of the diimine ligand. However, insertion can be facilitated by one-electron oxidation. Thus, oxidation of [(^HL^iPr)CrR(THF)] [^HL^iPr = Ar–N=C(H)–(H)C=N–Ar in which Ar = 2,6-diisopropylphenyl and R = CH₂SiMe₃ or CH₃] with [(C₅H₅)₂Fe]⁺ presumably forms [(^HL^iPr)CrR(THF)]⁺, which contains a neutral diimine ligand coordinated to Cr^II. This cationic complex apparently undergoes immediate insertion of the C=N bond of the diimine ligand into the Cr–alkyl bond, followed by C–H activation of the isopropyl substituent of an N–aryl group on the diimine ligand. DFT calculations confirm that [(^HL^iPr)CrR(THF)]⁺ contains a neutral innocent diimine ligand that undergoes C=N bond insertion into the Cr–R bond.

A series of organochromium complexes bearing α-diimine ligands has been prepared. The compounds contain diimine ligands in the neutral, singly, and doubly reduced states. All the complexes resist alkyl migration to the diimine backbone, except for a cationic alkyl-Cr^II species that features a neutral diimine ligand. A C=N insertion mechanism followed by a hydride shift is proposed.

Directing Protons to the Dioxygen Ligand of a Ruthenium(II) Complex with Pendent Amines in the Second Coordination Sphere

Directing Protons to the Dioxygen Ligand of a Ruthenium(II) Complex with Pendent Amines in the Second Coordination Sphere:

Proton relay: A side-on Ru–O₂ complex with pendent amines in the ligand backbone has been synthesized to model proton delivery in O₂ reduction (see scheme and structure; red O, purple Ru, blue N, yellow P). Protonation occurs at the amine near the O₂ ligand, forming a hydrogen bond between the ammonium ion and the O₂ ligand, leading to small increase in OO bond length.

Ruthenium arene complex of DuBois' PNP ligand

A Mild Ligand-Free Iron-Catalyzed Liberation of Alcohols from Allylcarbonates

A Mild Ligand-Free Iron-Catalyzed Liberation of Alcohols from Allylcarbonates:

Organic LettersDOI: 10.1021/ol202270g

Bottom catalyst formula is incorrect

Pentacoordinate iron complexes as functional models of the distal iron in [FeFe] hydrogenases

Pentacoordinate iron complexes as functional models of the distal iron in [FeFe] hydrogenases:

Chem. Commun., 2011, Advance Article
DOI: 10.1039/C1CC14449A, Communication

Maryline Beyler, Salah Ezzaher, Michael Karnahl, Marie-Pierre Santoni, Reiner Lomoth, Sascha Ott
Mononuclear pentacoordinate Fe(II) complexes with a free coordination site were prepared as mimics of the distal Fe (Fe_d) in the active site of [FeFe] hydrogenases. The complexes catalyze the electrochemical reduction of protons at mild overpotential.
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Electrolyte tuning of electrode potentials: the one electron vs. two electron reduction of anthraquinone-2-sulfonate in aqueous media

Electrolyte tuning of electrode potentials: the one electron vs. two electron reduction of anthraquinone-2-sulfonate in aqueous media:

Chem. Commun., 2011, Advance Article
DOI: 10.1039/C1CC14191K, Communication

Qian Li, Christopher Batchelor-McAuley, Nathan S. Lawrence, Robert S. Hartshorne, Richard G. Compton
Ion paring effect between supporting electrolyte and reactive intermediate species can tune the ionic environment in an aqueous solution.
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Computational Investigations into Hydrogen-Atom Abstraction from Rhodium Hydride Complexes by Methyl Radicals in Aqueous Solution

Computational Investigations into Hydrogen-Atom Abstraction from Rhodium Hydride Complexes by Methyl Radicals in Aqueous Solution:

Abstract

The controversy in the reported kinetics for the hydrogen-atom abstraction reaction by methyl radicals for cis- and trans-[(Cyclam)Rh^IIIHCl]⁺ and trans-[(Cyclam)(H₂O)Rh^IIIH]²⁺ has been resolved by studying several feasible mechanistic pathways with density functional theory. The only low-energy reaction mechanism predicted by these calculations involves a single-step radical-propagation mechanism in which the methyl radical simply abstracts the Rh bound H atom from the complex to form methane and the reduced Rh product. Previous experimental work on the chloride and aquo complexes suggested contradictory kinetic isotope effect (KIE) values of 0.66 ± 0.30 and 1.42 ± 0.07 as well as rate constants for the reaction differing by four orders of magnitude. The calculated mechanism predicts a KIE value of 1.08 and a high reaction rate. The alternative mechanisms are described briefly.

The controversy in the reported kinetics for the hydrogen-atom abstraction reaction bymethyl radicals for cis- and trans-[(Cyclam)Rh^IIIHCl]⁺ and trans-[(Cyclam)(H₂O)Rh^IIIH]²⁺ has been resolved by studying several feasible mechanistic pathways with density functional theory.

Predicting the Air Stability of Phosphines

Predicting the Air Stability of Phosphines:

Organometallics

DOI: 10.1021/om200070a

[Report] Efficient Dehydrogenation of Formic Acid Using an Iron Catalyst

[Report] Efficient Dehydrogenation of Formic Acid Using an Iron Catalyst: Iron-catalyzed hydrogen generation raises prospects for a cheap hydrogen storage medium.

Authors: Albert Boddien, Dörthe Mellmann, Felix Gärtner, Ralf Jackstell, Henrik Junge, Paul J. Dyson, Gábor Laurenczy, Ralf Ludwig, Matthias Beller

[Perspective] Chemistry: Ironing Out Hydrogen Storage

[Perspective] Chemistry: Ironing Out Hydrogen Storage: The use of formic acid for storage of hydrogen fuel is enabled by an iron compound that catalyzes dehydrogenation

Author: Sascha Ott

Nature-Driven Photochemistry for Catalytic Solar Hydrogen Production: A Photosystem I–Transition Metal Catalyst Hybrid

Nature-Driven Photochemistry for Catalytic Solar Hydrogen Production: A Photosystem I–Transition Metal Catalyst Hybrid:

Journal of the American Chemical Society

DOI: 10.1021/ja206012r

Peptide-Bound Dinitrosyliron Complexes (DNICs) and Neutral/Reduced-Form Roussin’s Red Esters (RREs/rRREs): Understanding Nitrosylation of [Fe–S] Clusters Leading to the Formation of DNICs and RREs Using a De Novo Design Strategy

Peptide-Bound Dinitrosyliron Complexes (DNICs) and Neutral/Reduced-Form Roussin’s Red Esters (RREs/rRREs): Understanding Nitrosylation of [Fe–S] Clusters Leading to the Formation of DNICs and RREs Using a De Novo Design Strategy:

Inorganic Chemistry

DOI: 10.1021/ic201529e

Mechanistic Study on the Fluorination of K[B(CN)4] with ClF Enabling the High Yield and Large Scale Synthesis of K[B(CF3)4] and K[(CF3)3BCN]

Mechanistic Study on the Fluorination of K[B(CN)4] with ClF Enabling the High Yield and Large Scale Synthesis of K[B(CF3)4] and K[(CF3)3BCN]:

Inorganic Chemistry

DOI: 10.1021/ic201319h

Efficient Hydrogen Production from Alcohols under Mild Reaction Conditions

Efficient Hydrogen Production from Alcohols under Mild Reaction Conditions:

Run out of gas? A protocol for the title transformation under mild reaction conditions has been developed. Highest activities are found with an in situ catalyst system consisting of a 1:1 mixture of an HPNP^iPr ligand and [RuH₂(PPh₃)₃CO]. A turnover frequency of up to 14 145 h⁻¹ and turnover number of more than 40 000 have been achieved for production of hydrogen gas from isopropyl alcohol.

Coordinating ability of anions and solvents towards transition metals and lanthanides

Coordinating ability of anions and solvents towards transition metals and lanthanides:

Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT11000D, Paper

Raul Diaz-Torres, Santiago Alvarez
A new index deduced from a crystal structure analysis quantifies the coordinating power of solvents and weakly coordinating anions.
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Comparison of the Reactivity of Platinum(II) and Platinum(0) Complexes with Iminophosphine and Phosphinocarbonyl Ligands

Comparison of the Reactivity of Platinum(II) and Platinum(0) Complexes with Iminophosphine and Phosphinocarbonyl Ligands:

Organometallics DOI: 10.1021/om2005113

related to our PCHO project (see DoE grant proposal)

Synthesis and Reactivity of the Anionic Iridium(III) Complex [Cp*Ir(OTf)3][Ag{tBu2P(heptanoyl)}]

Synthesis and Reactivity of the Anionic Iridium(III) Complex [Cp*Ir(OTf)3][Ag{tBu2P(heptanoyl)}]:

OrganometallicsDOI: 10.1021/om200639e

Probably not very useful, but interesting since we do so much Cp*Ir work.

On the Diels–Alder Approach to Solely Biomass-Derived Polyethylene Terephthalate (PET): Conversion of 2,5-Dimethylfuran and Acrolein into p-Xylene

On the Diels–Alder Approach to Solely Biomass-Derived Polyethylene Terephthalate (PET): Conversion of 2,5-Dimethylfuran and Acrolein into p-Xylene:

Dean Toste et al. Chem-Eur J: Polyethylene terephthalate (PET) is a polymeric material with high global demand. Conventionally, PET is produced from fossil-fuel-based materials. Herein, we explored the feasibility of a sustainable method for PET production by using solely bio-renewable resources. Specifically, 2,5-dimethylfuran (derived from lignocellulosic biomass through 5-(hydroxymethyl)furfural) and acrolein (produced from glycerol, a side product of biodiesel production) were converted into the key intermediate p-xylene (a precursor of terephthalic acid). This synthesis consists of a sequential Diels–Alder reaction, oxidation, dehydration, and decarboxylation. In particular, the pivotal first step, the Diels–Alder reaction, was studied in detail to provide useful kinetic and thermodynamic data. Although it was found that this reaction requires low temperature to proceed efficiently, which presents a limitation on economic feasibility on an industrial scale, the concept was realized and bio-derived p-xylene was obtained in 34 % overall yield over four steps.

Making PET as green as grass: Polyethylene terephthalate (PET) can be prepared from solely bio-renewable sources by converting 2,5-dimethylfuran and acrolein into the key intermediate p-xylene (see scheme). This atom-economic route consists of a sequential Diels–Alder reaction, oxidation, dehydrative aromatization and decarboxylation. We examined the feasibility of this process with an emphasis on the Diels–Alder reaction step.

Not super-relevant to our approach, but the article highlights possible directions. The main catch is that even the largest scale chemicals do not approach the scale of fuels. And our program is focused on fuels.

Basic ancillary ligands promote O-O bond formation in iridium-catalyzed water oxidation: A DFT study

Basic ancillary ligands promote O-O bond formation in iridium-catalyzed water oxidation: A DFT study:

Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10660K, Paper

Laia Vilella, Pietro Vidossich, David Balcells, Agusti Lledos
A DFT(B3LYP) study on Ir-catalyzed water oxidation shows that the energy barrier associated with the critical O-O bond formation step is lowered by increasing the basicity of the ancillary ligands.
The role of M-C bonds to stabilizing M=O and M-OOH bonds is possibly relevant to our collaboration with Gewirth group.

Structural Study-Guided Development of Versatile Phase-Transfer Catalysts for Asymmetric Conjugate Additions of Cyanide

Structural Study-Guided Development of Versatile Phase-Transfer Catalysts for Asymmetric Conjugate Additions of Cyanide:

Unprecedented phase-transfer catalysts for the first example of an organocatalytic asymmetric conjugate addition of cyanide with acetone cyanohydrin are reported (see scheme). Utilizing an accessible cupreidinium salt and a cyanation reagent suitable for industrial scale, this reaction holds significant promise for practical asymmetric synthesis. The catalysts were developed as a result of key structural insights gained by X-ray analysis.

Novel source of CN-?

Controlled Aqueous Atom Transfer Radical Polymerization with Electrochemical Generation of the Active Catalyst

Controlled Aqueous Atom Transfer Radical Polymerization with Electrochemical Generation of the Active Catalyst:

Enhanced control: Electrochemically mediated atom transfer radical polymerization (ATRP) allows easy modulation of the overall rate and control of polymerization through the variation of an external applied potential, E_app (see picture). This method has been successfully applied to aqueous ATRP of oligo(ethylene glycol) methyl ether methacrylate (OEOMA₄₇₅) catalyzed by Cu/tris(2-pyridylmethyl)amine.
We could probably contribute to this theme with Chris Letko's ligands.  This topic (ATRP) would be a good for a future literature talk).

Comparison of the photochemistry of organometallic N-heterocyclic carbene and phosphine complexes of manganese

Comparison of the photochemistry of organometallic N-heterocyclic carbene and phosphine complexes of manganese:

Chem. Commun., 2011, Advance Article
DOI: 10.1039/C1CC14467G, Communication

Madeeha Batool, Thomas A. Martin, M. Abu Naser, Michael W. George, Stuart A. Macgregor, Mary F. Mahon, Michael K. Whittlesey
Agostic interactions in the unsaturated intermediates ([small eta]⁵-C₅H₄Me)Mn(L)(CO) (L = NHC, PPh₃) are revealed by time-resolved IR studies and DFT calculations.
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Preparation and Reactivity of a Nickel Dihydride Complex

Preparation and Reactivity of a Nickel Dihydride Complex:

A generous donor: A dinuclear octahedral bis(μ-hydrido)dinickel(II) complex (see picture; C gray, H black, N blue, Ni green) acts as an electron donor to reduce electron acceptors such as methyl viologen. The complex is proposed as a functional model for the dihydride intermediate of an NiRu hydrogenase mimic and, by extension, of [NiFe]hydrogenase itself.
by Seiji Ogo's Group: Very relevant to us. Note the presence of two picolinyl groups, not just TPA and not tris(picolinyl)amine. The redox and magnetic properties of this species (high spin?) would be interesting.  Note his reference to viologens and his effort to connect to the enzyme.

Balance between Fluorescence Enhancement and Association Affinity in Fluorescent Heteroditopic Indicators for Imaging Zinc Ion in Living Cells

Balance between Fluorescence Enhancement and Association Affinity in Fluorescent Heteroditopic Indicators for Imaging Zinc Ion in Living Cells:

Inorganic Chemistry DOI: 10.1021/ic201728f

Dual Coordination Modes of Ethylene-Linked NP2 Ligands in Cobalt(II) and Nickel(II) Iodides

Dual Coordination Modes of Ethylene-Linked NP2 Ligands in Cobalt(II) and Nickel(II) Iodides:

Inorganic Chemistry

DOI: 10.1021/ic201213c