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Jay Groves Named Rayson Huang Visiting Lecturer at the University of Hong Kong

Nov. 11, 2014 —Congratulations to Professor Jay Groves of Princeton University on his selection as the Rayson Huang Visiting Lecturer in Chemsitry at the University of Hong Kong for 2015. This lectureship was established in 1987 to honor Dr. Rayson Huang, and is given annually to a prominent chemist  to participate in teaching and research activities at the University of Hong Kong for a period of up to one month.

Jay Groves to Receive 2015 ACS Award in Inorganic Chemistry

Aug. 22, 2014 — Prof. John T. Groves (Princeton University) has been named the recipient of the 2015 ACS Award in Inorganic Chemistry, sponsored by the Aldrich Chemical Company, LLC. The award will be presented in March 2015 at the ACS National Meeting in Denver.

CCHF Iodate Chemistry Highlighted in C&EN

Aug. 18, 2014In news from last week's ACS National Meeting, held in San Francisco, C&EN highlighted the paper by T. Brent Gunnoe (University of Virginia) on the iodate chemistry for alkane oxidation developed by the CCHF. The process uses simple iodate salts, along with catalytic amounts of chloride, to selectively oxidize methane, ethane and propane to trifluoromethyl esters, precusrsors to alcohols.

  

Science Highlights Roy Periana's Efforts to Break C-H Bonds

In the June 27, 2014 issue of Science, staff writer Robert Service profiles the career of Roy Periana (The Scripps Research Institute). The article describes Roy's career-long quest for a cheaper, better way to transform methane into liquid chemical fuels and feedstocks and highlights the recent CCHF-funded work by the Periana Group on use of thallium and lead-based catalysts in the presence of acetic acid to convert methane to an alcohol ester.

CCHF Post-Doc/Former Grad Student Receives a 2013 Extraordinary Potential Prize for Outstanding Chinese Students Studying Abroad

May 23, 2014 — Congratulations to Wei Liu, a CCHF post-doctoral researcher and recent Ph. D. student in the laboratory of John Groves (Princeton University) on his receipt of the 2013 Extraordinary Potential Prize for Outstanding Chinese Students Studying Abroad from the China Scholarship Council. Wei was one of six students to receive this award, selected based on their academic and research accomplishments. This award recognizes Wei's outstanding work developing catalysts for CH fluorination and chlorination, including the development of the first aliiphatic C-H fluorination reaction using an easily handled fluoride source. For more information on this award see http://www.princeton.edu/chemistry/news/archive/?id=12907.

CCHF Undergraduate Student Receives Fulbright Student Fellowship Award

 

Mar. 31, 2014  — Congratulations to Dina Sharon of Princeton University for receiving a Fulbright U.S. Student Award to study in Israel for the 2014-2015 academic year. The Fulbright Program sponsors research by U.S. students and scholars in other countries in an effort to promote cross-cultural understanding.

Dina, a student in John Groves' Lab, has been studying the functionalization of C–H bonds with high valent iodine using computational chemistry. In the CCHF, she has collaborated with the Gunnoe (University of Virginia), Goddard (Caltech), Ess (Brigham Young University) and Cundari (University of North Texas) groups, and she credits these collaborations with providing insight and technical knowledge for her computational research as well as an understanding of the importance of collaboration in addressing modern scientific challenges. From Dina's narrative about her senior thesis research, "The Groves lab and the Center for Catalytic Hydrocarbon Functionalization fostered both my curiosity about specific scientific concepts and my enthusiasm for research. These traits will help me as a Fulbright Award recipient. C-H bonds are ubiquitous but often inert. If they could be activated, they would represent a valuable starting point for fuels and for the construction of chemical building blocks. Seeing, and contributing to, the CCHF’s work, I have been inspired as I see significant progress being made on this challenging chemical problem … In addition, the CCHF’s collaborative culture has made me enthusiastic about doing further research. Professor Goddard (CalTech), Professor Ess (Brigham Young University), Professor Cundari (University of North Texas), and members of their groups have generously shared their knowledge, from providing new insight into my data to suggesting DFT computational basis sets. This has greatly helped my research. Working with different groups, incorporating a wide variety of perspectives, I have seen firsthand how collaboration breeds synergy. During our conference calls, thousands of miles may separate us, but it feels as if we are in the same room, as we figure out solutions to problems on the frontiers of chemistry."  

In Israel, Dina will work in the laboratory of Professor Sason Shaik at the Hebrew University of Jerusalem. Her research will continue to focus on computational chemistry applied to C–H functionalization with a focus on modification of the SyrB2 enzyme to enhance its selectivity for formation of carbon-chlorine bonds.

Science Paper from Ess and Periana Groups

Main-Group Compounds Selectively Oxidize Mixtures of Methane, Ethane and Propane to Alcohol Ethers

Mar. 14, 2014 — In this paper published in Science, the Ess (Brigham Young University) and Periana (The Scripps Research Institute) Groups report a novel approach using main-group catalysts for the conversion of alkanes to mono-functionalized products. THey report that thallium(III) and lead(IV) cations stoichiometrically oxidize methane, ethane, and propone to the corresponding alcohol ethers at 180 C with selectivities greater than 95%. This addresses a key challenge for the inexpensive conversion of natural gas to liquid fuels and precursors to higher value chemicals. This paper has generated substantial coverage in the press, including:

http://cen.acs.org/articles/92/i11/Natural-Gas-Upgrade.html

http://m.csmonitor.com/Environment/2014/0314/Lab-results-raise-question-Do-we-need-oil-if-we-have-natural-gas

http://news.yahoo.com/experts-see-cheaper-easier-way-turn-natural-gas-181143158.html

http://www.reuters.com/article/2014/03/13/science-naturalgas-idUSL2N0M929620140313

business week

 

Mechanistic Study of the Oxidation of a Methyl Platinum (II) Complex with O2 in Water: PtIIMe-to- PtIVMe and PtIIMe-to-PtIVMe2 Reactivity

Mar. 7, 2014 — The Vedernikov (University of Maryland) and Goddard (California Institute of Technology) Groups report on the pH dependence of the pathways for oxidation of (dpms)PtIIMe(OH2) complex with dioxygen in water.

 

Density Functional Theory Study of Oxygen-Atom Insertion into Metal-Methyl Bonds of Iron(II), Ruthenium(II), and Osmium(II) Complexes: Study of Metal-Mediated C-O Bond Formation

Feb. 27, 2014 — This paper from the Cundari (University of North Texas) and Gunnoe (University of Virginia) Groups reports DFT analysis of oxygen insertion into a metal-carbon bond of Cp*M(CO)(OPy)R where M = Fe, Ru, Os. The calculations predict that oxygen-atom insertion through a concerted single-step organometallic Baeyer-Villiger pathway is lower in energy than a two-step pathway via a metal- oxo intermediate.

 

Catalyst Activation by Loss of Cyclopentadienyl Ligands in Hydrogen Transfer Catalysis with Cp*IrIII Complexes

Feb.21, 2014— In this ACS Catalysis paper, the Crabtree Group (Yale University) proposes a novel catalyst activation method for transfer hydrogenation based on the lability of the cyclopentadienyl ligand.

 

Mechanism of O2 Activation and Methanol Production by (Di(2-pyridyl)methanesulfonate)PtIIMe(OHn)(2-n)- Complex from Theory with Validation from Experiment

Feb. 7, 2014 — This paper from the Goddard (California Institute of Technology) and Vedernikov (University of Maryland) Groups describes DFT analysis of the title reaction. A pH dependence was found for both oxygen activation and O — O bond cleavage. The dpms ligand was found to facilitate Pt(II) oxidation both enthalpically and entropically.

Hydrogen-Transfer Catalysis with Cp*IrIII Complexes: The Influence of the Ancillary Ligands

Dec. 5, 2013The Crabtree Group (Yale University) assayed 14 Cp*IrIII complexes in hydrogen-transfer catalysis from isopropyl alcohol to acetophenone to investigate ligand effects. The study found that having both N-heterocyclic carbine ligands in monodentate form is necessary for efficient catalysis.

Efficient water oxidation catalyzed by homogeneous cationic cobalt porphyrins with critical roles for the buffer base

Nov. 13, 2013 — The Groves Group (Princeton University) reports mechanistic studies of a series of single-site homogeneous water oxidation catalysts based on cationic cobalt porphyrins. The reported catalysts are effective electrochemical water oxidation catalysts under mild conditions at neutral pH.

Activation of carbon–hydrogen bonds and dihydrogen by 1,2-CH-addition across metal–heteroatom bonds

Oct. 23, 2013—This perspective article from the Cundari (University of North Texas) and Gunnoe (University of Virginia) Groups discusses 1,2-CH-addition across d0 transition metal imido complexes and compares these with reactions involving d6 and d8 metal complexes.  

Aerobic C-H Acetoxylation of 8-Methylquinoline in PdII-Pyridinecarboxylic Acid Systems: Some Structure-Reactivity Relationships

Aug. 30, 2013—The Vedernikov Group (University of Maryland) studied the relationship between the structure and reactivity of palladium(II) carboxylate catalysts in the acetoxylation of 8-methylquinoline as a model substrate with O2 as oxidant. The C—H oxidation step was found to be rate-limiting, with the chelate ring size and the chelate ring strain proposed to be the key factors affecting this step.

Using Reduced Catalysts for Oxidation Reactions: Mechanistic Studies of the "Periana-Catalytica" System for CH4 Oxidation

Aug. 13, 2013— The Goddard (California Institute of Technology) and Periana (The Scripps Research Institute) Groups report that the oxidation of methane to methanol using the Periana-Catalytica (Bpym)PtCl2 catalyst in concentrated sulfuric acid operates by a more complex mechanism than previously reported. Increasing the rate of oxidation of PtII to PtIV was found to lead to stable systems with higher TOF.

Computational study of carbon-hydrogen bond deprotonation by alkali metal superbases

Aug. 13, 2013— Using density functional theory calculations, the Cundari (University of North Texas), Periana (The Scripps Research Institute) and Ess (Brigham Young University) Groups analyzed deprotonation of C–H bonds by alkali metal amide "superbases". Studies included the role of alkali metal, amide substituents, solvent and substrate.

Precursor Transformation during Molecular Oxidation Catalysis with Organometallic Iridium Complexes

Aug. 5, 2013—The Crabtree (Yale University) and Ess (Brigham Young University) groups provide experimental and computational evidence that Cp* is a sacrificial placeholder ligand in organometallic Cp*IrIII complexes used in water and CH-oxidation catalysis.

 

Computational study of carbon-hydrogen bond deprotonation by alkali metal superbases

Aug. 5, 2013—In this paper from the Cundari (University of North Texas), Periana (The Scripps Research Institute) and Ess (Brigham Young University) groups, density functional theory calculations are used to study the role of alkali metal, amide substituents, solvent and substrate in deprotonation of hydrocarbon C-H bonds by alkali metal amide superbases.

Manganese-Catalyzed Oxidative Benzylic C—H Fluorination by Fluoride Ions

Apr. 24, 2013— The Groves Group (Princeton University) reports a general Mn-catalyzed method for formation of benzylic fluorides directly from C–H bonds using simple and easily handled nucleophilic fluoride reagents.

Bob Crabtree to Receive 2013 Centenary Prize

Apr. 18, 2013—

Congratulations to Professor Robert Crabtree of Yale University, a CCHF PI, on his selection as a 2013 winner of the Centenary Prize of the Royal Chemical Society. The Centenary Prize, established in 1947 to commemorate the 1941 centenary of the Chemical Society, is awarded annually to up to three outstanding chemists from overseas to give lectures in the British Isles.

The Critical Role of Phosphate in Vanadium Phosphate Oxide for the Catalytic Activation and Functionalization of n-Butane to Maleic Anhydride

Apr. 16, 2013— Using density functional theory (DFT), the Goddard Group (California Institute of Technology) studied the mechanism of catalysis on the vanadium phosphorous oxide surface for oxidation of n-butane to maleic anhydride, an important industrial reaction.

CCHF Graduate Student Daria Huang Receives NSF Fellowship

Apr. 10, 2013—Congratulations to Daria Huang, a graduate student in the Crabtree Group at Yale University, for receiving a NSF Graduate Research Fellowship to pursue research on chemical catalysis. The fellowship provides three years of support, including an annual stipend and cost of education allowance to the institution. Daria, who received a B.S. from Georgetown University, was one of 2,000 recipients of the prestigious fellowship.

Cp* Iridium Precatalysts for Selective C– H Oxidation with Sodium Periodate As the Terminal Oxidant

Feb. 6, 2013— The Crabtree (Yale University) and Periana (The Scripps Research Institute) groups report that sodium periodate is a mild and efficient terminal oxidant for C–H oxidation with Cp*Ir complexes as precatalysts.

Variable Pathways for Oxygen Atom Insertion into Metal–Carbon Bonds: The Case of Cp*W(O)2(CH2SiMe3)

Dec. 27, 2012— In this paper, the Gunnoe (University of Virginia) and Cundari (University of North Texas) Groups establish that Cp*WVI complexes can undergo clean oxygen atom insertion by at least three different pathways, including an OMBV pathway. The studies of the OMBV reaction suggest that catalysts with nucleophilic hydrocarbyl groups that are tolerant of water should be amenable for this process.

Complete methane-to-methanol catalytic cycle: A DFT study of oxygen atom transfer from N2O to late-row (M=Ni, Cu, Zn) β-diketiminate C—H activation catalysts

Dec. 27, 2012 —This computational study by the Cundari Group (University of North Texas) indicates that  methane C-H activation and functionalization is thermodynamically and kinetically feasible using N2O as an oxidant and a β-diketiminate supported metal catalyst when the metal is Ni, Cu or Zn. The methane to methanol transformation is exergonic for the Ni system, which is the more favorable metal among the metals modeled. This study also highlights the challenge in this catalytic cycle of removal of methanol from the metal center to avoid further oxidation.  

Nickelation of PCP- and POCOP-Type Pincer Ligands: Kinetics and Mechanism

Dec. 27, 2012 —The Ess Group (Brigham Young University) reports computational and experimental studies of  the C—H metalation step involved in the formation of PCP- and POCOP- type nickel complexes. Metalation of PCP ligands was found to be  more facile in comparison to their POCOP counterparts due to the greater donor character of phosphine moieties.  

Computational Hammett analysis of redox based oxy-insetion by Pt(II) complexes

Dec. 3, 2012 The Cundari Group (University of North Texas) studied oxy-insertion into platinum–aryl bonds using computational Hammett analysis. They concluded that the metal and oxidant are the most important factors in controlling the oxy-insertion functionalization reaction crucial to selective oxidation of methane, benzene and other hydrocarbons.

Redox-active ligands in catalysis

Oct. 22, 2012— This review from the Crabtree Group (Yale University) focuses on ligand-based, non-singlet state intermediates and their participation in catalytic processes and related stoichiometric transformations.

Science Paper from Goddard and Groves Groups

Oxidative Aliphatic C-H Fluorination with Fluoride Ion Catalyzed by a Manganese Porphyrin

September 14, 2012 — In this paper published in Science, the Goddard (CalTech) and Groves (Princeton University) groups report discovery of a manganese porphyrin complex that catalyzes fluorination of aliphatic C-H bonds by fluoride ion under mild conditions in conjunction with stoichiometric oxidation by iodosylbenzene. The fluorinating agent was identified as trans-difluoroMn(IV)(TMP).

Proton-Coupled Electron Transport

August 25, 2012— This review from the Meyer (University of North Carolina at Chapel Hill) and Ess (Brigham Young University) groups is a broad, comprehensive review of the role of Proton-Coupled Electron Transfer in chemistry and biology and its implications for catalysis and energy conversion.

Flavin-Catalyzed Insertion of Oxygen into Rhenium-Methyl Bonds

August 2, 2012 — In this communication, the Gunnoe (University of Virginia), Cundari (University of North Texas) and Groves (Princeton University) groups report that experimental and DFT studies indicate that flavins and related molecules catalyze the insertion of oxygen into metal-carbon bonds through a Baeyer-Villiger-like transition state.

Theory of Late-Transition-Metal Alkyl and Heteroatom Bonding: Analysis of Pt, Ru, Ir, and Rh Complexes

July 17, 2012 — This study by the Ess and Gunnoe Groups uses density functional and ab initio methods to calculate, compare and analyze bond energies of late-transition-metal alkyl and heteroatom complexes. Pauli repulsion was found to decrease along the alkyl to heteroatom ligand series and therefore does not control M—X bond strengths. However, Pauli repulsion was found to play an important role when comparing M—CH3  and M—NH2 bond energies for some of the complexes studied. Correlation between M—X and H—X bond dissociation energies was good.

Mechanistic Study of Oxy Insertion into Nickel-Carbon Bonds with Nitrous Oxide

July 6, 2012 —This computational study from the Cundari Group (University of North Texas) explores the mechanisms of oxy insertion into metal carbon bonds of the NiII alkyl complexes reacting with nitrous oxide (N2O) recently reported by Hillhouse and co-workers. Nitrous oxide was found to be critical for net oxy insertion due to the substantial thermodynamic advantage of N2 expulsion. Understanding of this reaction could lead to design of catalysts for selective partial oxidation of hydrocarbons using earth-abundant 3d metals.

Particle Formation during Oxidation Catalysis with Cp* Iridium Complexes

June 6, 2012— This paper from the Crabtree Group describes the use of time-resolved dynamic light scattering to study particle formation during oxidation catalysis with organometallic iridium complexes using chemical oxidants. The formation of a deep purple-blue color was found not to be indicative of particle formation during oxidation catalysis with molecular iridium precursors.

Brian Trewyn to Join Colorado School of Mines

May 8, 2012 —Congratulations to Brian Trewyn, a CCHF PI, who has accepted a position as tenure tracked assistant professor of inorganic chemistry at the Colorado School of Mines, starting in August 2012. His research at Mines will continue to focus on supported catalyst design, sequestering high value naturally produced molecules, and the design and synthesis of new porous materials including carbon and non carbon conductive materials.

John Groves Elected to National Academy of Sciences

May 2, 2012 — Congratulations to Prof. John T. "Jay" Groves of Princeton University, a CCHF PI and member of the CCHF Management Committee, on his election yesterday to membership in the National Academy of Sciences. Groves is one of 84 new members recognized for their distinguished and continuing achievements in original research.

Reversible hydrogen storage using CO2 and a proton-switchable iridium catalyst in aqueous media under mild temperatures and pressures

Apr. 18, 2012 —The Periana group (The Scripps Research Institute) reports a novel homogeneous iridium catalyst with a proton-responsive ligand that uses CO2 and hydrogen to store energy in formic acid. This is the first reversible and recyclable hydrogen storage system using CO2, formate and formic acid that operates under near ambient conditions.

Recent Publications from the Meyer Group (University of North Carolina at Chapel Hill)

Apr. 16, 2012— Two recent publications from the Meyer group are highlighted below:

Photostability of Phosphonate-Derivatized, RuII Polypyridyl Complexes on Metal Oxide Surfaces

Desorption and photochemical processes of the title complexes on TiO2 and ZrO2 films were found to be dependent upon solvent, anion, semiconductor and presence of oxygen. Based on the anion and solvent dependence of  kphoto, the photoreaction likely involves ligand substitution initiated by population of metal centered d-d states.

Nonaqueous Electrocatalytic Oxidation of the Alkylaromatic Ethylbenzene by a Surface Bound RuV(O) Catalyst

This letter reports electrocatalytic oxidation of ethylbenzene, toluene and cumene in polycarbonate/water mixtures with a RuV(O) catalyst attached to nanocrystalline Sn(IV)-doped In2O3 (nanoITO) electrodes. A faradaic efficiency of 95% was found for electrocatalytic oxidation of ethylbenzene to acetophenone.

The Role of Proton Coupled Electron Transfer in Water Oxidation

This paper presents recent studies regarding water oxidation, a key half reaction in solar fuel schemes, which is dominated by proton coupled electron transfer. A new pathway for the O/O bond forming step, Atom-Proton Transfer, was identified from kinetic, mechanistic and DFT studies. Addition of proton acceptor bases was found to provide significant rate enhancement. Accelerated water oxidation in propylene carbonate as solvent with water added as a stoichiometric reagent is also reported.

Proton-coupled electron transfer at modified
electrodes by multiple pathways

Investigations  of  the mechanisms of single site water or hydrocarbon oxidation catalysis with polypyridyl Ru complexes is reported, with a focus on identifying microscopic phenomena associated with electrochemical conversion of two oxidation states.

Designing Catalysts for the Functionalization of Unactivated C-H Bonds Based on the CH Activation Reaction

Apr. 11, 2012— This account from the Periana Group (The Scripps Research Institute) describes ongoing studies of the acceleration by basic solvents of CH activation and M-R functionalization reactions based on more electron-rich metals. The researchers believe that exploring the continuum of base-or acid-modulated (BAM) catalysis could lead to new catalytic cycles for CH activation as well as conversion of other small molecules.

The para-substituent effect and pH-dependence of the organometallic Baeyer-Villiger oxidation of rhenium-carbon bonds

Mar. 29, 2012— This publication from the Goddard (CalTech), Gunnoe (University of Virginia) and Periana (Scripps Research Institute) groups describes DFT studies of oxidation of phenylrhenium trioxide by hydrogen peroxide in the aqueous phase and studies of the pH-dependence of this reaction. Substituting an electron-donating functional group in the para-position of phenyl was found to lower the migration barrier. However, in contrast to the organic Baeyer-Villiger oxidation, the para-substitution was found to push electon density to Re, slowing the reaction. Due to these competing effects, and the dependence of the resting state on pH and concentration, para-substitution was found to have surprisingly little effect on the reaction rate.

Water Oxidation Intermediates Applied to Catalysis: Benzyl Alcohol Oxidation

Mar. 2, 2012 — In this Communication, the Meyer group (University of North Carolina at Chapel Hill) identifies four distinct intermediates in electrocatalytic benzyl alcohol oxidation with high oxidation state Ru oxo complexes. The study points to the importance of multiple reactive intermediates under catalytic water oxidation conditions.

Direct Functionalization of M-C (M= PtII, PdII) Bonds Using Environmentally Benign Oxidants, O2 and H2O2

Mar. 1, 2012 — This research account by Andrei Vedernikov (University of Maryland) describes development of novel organometallic platinum and palladium catalysts for M-C bond functionalization and selective hydrocarbon C-H oxidation using "green" oxidants, O2 or H2O2. This paper introduces catalysts incorporating facially chelating semilabile ligands.

NY Times OP-ED "The Methanol Alternative to Gasoline"

Feb. 27, 2012 — The Feb. 23, 2012 New York Times published an OP-ED by Tom Ridge and Mary E. Peters regarding the need for the United States to make greater use of its large natural gas resources by converting natural gas to methanol for use as a transportation fuel. The editorial calls for Congress to pass legislation requiring that new automobiles sold in the US be capable of operating on methanol as well as ethanol, gasoline and alcohol-gasoline blends.

C-H Bond Activation of Methane by PtII-N-Heterocyclic Carbene Complexes. The Importance of Having the Ligands in the Right Place at the Right Time

Feb. 16, 2012 — This computational study from the Cundari group (University of North Texas) focuses on catalyst models with N-heterocyclic carbine supporting ligands and their ability to activate C-H bonds. The analysis highlights the importance of having the ground state active species in the correct conformation for C-H bond scission in the subsequent transition state.  

Carbon–Oxygen Bond Formation via Organometallic Baeyer–Villiger Transformations: A Computational Study on the Impact of Metal Identity

Feb. 16, 2012 — This publication from the Cundari (University of North Texas) and Gunnoe (University of Virginia) groups reports DFT studies of the impact of metal identity on O-atom insertions for the reaction [(bpy)xM(Me)(OOH0]n→[(bpy)xM(OMe)(OH)]n (x= 1 or 2; bpy = 2,2'-bipyridyl; n is varied to maintain the d-electron count at d6 or d8). Organometallic Baeyer-Villiger insertions were found to be favored by lower coordination numbers, earlier transition metals, and first-row (3d) transition metals.

Cp* Iridium Precatalysts for Selective C-H Oxidation via Direct Oxygen Insertion. A Joint Experimental/Computational Study

ACS Catalysis cover Crabtree

Feb. 15, 2012 — The cover of the February 2012 issue of ACS Catalysis showcases recent studies from the Crabtree group (Yale University) and colleagues from the Universitat Autònoma de Barcelona and Institut Charles Gerhardt, Université Montpellier regarding Cp*Ir complexes as precatalysts for C-H oxidation of alkanes. Experimental studies of the nature of the active species and DFT studies of the oxygen insertion mechanism were conducted for the C-H activation of cis-decalin by Cp*Ir(ppy)(Cl)(ppy = o-phenylpyridine).

Highlights of Recent CCHF Publications

Feb. 14, 2012 —Recent publications from the CCHF are highlighted below.

DFT modeling of a methane-to-methanol catalytic cycle via group 6 organometallics: The role of metal in determining the mode of C–H activation

 This recent publication from the Cundari group (University of North Texas) reports DFT studies of the reaction mechanism, involving C-H activation and oxygen-atom transfer, of Group 6 organometallics with respect to the oxy-inserton catalytic cycle for the conversion of methane to methanol.

Two Metals Are Better Than One in the Gold Catalyzed Oxidative Heteroarylation of Alkenes

Binuclear Au(II)- Au(III) complexes are proposed to be key intermediates in the mechanism for gold catalyzed oxidative heteroarylation. In this publication by the Goddard (CalTech) and Toste (Berkley) groups, experimental and DFT studies suggest that the key C-C bond forming reaction occurs via a bimolecular reductive elimination process.

DFT Study of the reactivity of methane and dioxygen with d10-L2M complexes

A recent DFT study that evaluates the kinetics and thermodynamics of oxidation of metal-alkyl bonds with respect to metal identity and supporting ligand is presented in this publication from the Cundari group (University of North Texas). This study could inform synthetic attempts to identify novel late transition metal catalysts for partial oxidation of methane.

Synthesis and Characterization of the k2-acac-O,O Complex OsIV(acac)2PhCl and Study of CH Activation with Benzene

 In this publication, the Goddard (CalTech) and Periana (The Scripps Research Institute) groups present the first known example of stoichiometric and catalytic, homogeneous, intermolecular CH activation of arenes by a discrete Os complex. Experimental and DFT data is presented.

Iridium complexes bearing a PNP ligand, favoring facile C(sp3)-H bond cleavage

The synthesis, structure and reactivity of new Iridium complexes for more efficient C-H activation chemistry is reported by the Peraina (The Scripps Research Institute) and Goddard (CalTech) groups.

Interfacial Electron Transfer Dynamics for [Ru(bpy)2((4,4'-PO3H2)2bpy)]2+ Sensitized TiO2 in a Dye-Sensitized Photoelectrosynthesis Cell: Factors Influencing Efficiency and Dynamics

This study by the Meyer group (University of North Carolina at Chapel Hill) reports use of nanosecond laser flash photolysis and photocurrent measurements to study hydrogen production in a dye-sensitized photoelectrosynthesis cell configuration.

Phosphoramidite Gold(I)-Catalyzed Diastereo- and Enantioselective Synthesis of 3,4-Substituted Pyrrolidines

The Goddard (CalTech) and Bergman (UC Berkeley) groups report the utility of phosphoramidite ligands in enantioselective AuI catalysis of cycloadditions of allenenes. The paper includes results of a DFT study of the cycloaddition mechanism. 

Making solar fuels by artificial photosynthesis

This paper from the Meyer group (University of North Carolina at Chapel Hill) discusses natural photosynthesis and reviews the progress in chemical approaches to artificial photosynthesis. Recent  advances in catalytic single-site water oxidation in dye-sensitive photoelectrosynthesis cells are presented.

Computational Study on the Mechanism and Selectivity of C–H Bond Activation and Dehydrogenative Functionalization in the Synthesis of Rhazinilam

This publication from the Ess group (Brigham Young University) studies the key platinum mediated C-H bond activation and functionalization of ( — ) –rhazinilam using DFT approximation methods, and extends the results to questions that may be germane to the general class of chelate assisted C-H activation reactions.

Alkane-oxidizing metalloenzymes in the carbon cycle

Metallomics cover Groves

In this critical review featured on the cover of the August 2011 issue of Metallomics, Rachel Narehood Austin and John Groves (Princeton University) review metalloenzymes for aerobic and anaerobic oxidation of alkanes in the environment. The review discusses the enzymes, reaction mechanisms, global distribution of organisms that oxidize alkanes and the environmental significance of metalloenzymes.

Photoinduced Stepwise Oxidative Activation of a Chromophore-Catalyst Assembly on TiO2

This Letter from the Meyer group (University of North Carolina at Chapel Hill) describes a molecular chromophore-catalyst assembly on TiO2 for organic/water oxidations in dye-sensitized photoelectrosynthesis cells.

Non-redox Oxy-Insertion via Organometallic Baeyer–Villiger Transformations: A Computational Hammett Study of Platinum(II) Complexes

The Cundari group (University of North Texas) reports the results of computational modeling of platinum-modified oxy-insertion into Pt— aryl bonds. This is part of on-going studies of the organometallic Bayer-Villiger reaction with low-valent systems known to activate C-H bonds.

Structures, Mechanisms, and Kinetics of Ammoxidation and Selective Oxidation of Propane Over the M2 Phase of MoVNbTeO Catalysts

In this publication from the Goddard group (CalTech), quantum mechanical calculations and ReaxFF are used in the first-principles-based study of  propane activation by the M2 phase of the MoVNbTeO multi-metal oxide catalysts for direct conversion of propane to acrylonitrile.

The magnetic and electronic structure of vanadyl pyrophosphate from density functional theory

In this paper from the Goddard group (CalTech), density functional theory with full three-dimensional periodicity was used to study the magnetic structure of vanadyl pyrophosphate, the most active phase of the vanadium phosphorous oxide catalyst system in the partial oxidation of n-butane to maleic anhydride.

Synthesis of osmium and ruthenium complexes bearing dimethyl (S,S)-2,2′-(pyridine-2,6-diyl)-bis-(4,5-dihydrooxazol-4-carboxylate) ligand and application to catalytic H/D exchange

The preparation of several new osmium and ruthenium complexes, using tridentate, neutral PyBox ligands, that are active for C—H activation of benzene is reported by the Goddard (CalTech) and Periana (The Scripps Research Institute) groups. The osmium complex was characterized by X-ray diffraction, and DFT studies corroborate that the osmium complex in acetic acid is more active for benzene C—H  than the Ru complex in basic solution.

Functionalization of Rhenium Aryl Bonds by O-Atom Transfer

This communication from the Goddard (CalTech), Gunnoe (University of Virginia) and Periana (The Scripps Research Institute) groups reports the rapid oxy-functionalization of aryltrioxorhenium to selectively generate the corresponding phenols. DFT studies reveal a Baeyer-Villiger type mechanism for the oxy-functionalization.

C-H Oxidation by Platinum Group Metal Oxo or Peroxo Species

This tutorial review from the Crabtree group (Yale University) surveys the preparation and reactivity of late-transition metal oxo and peroxo complexes for C-H oxidation.

An Iridium(IV) Species, [Cp*Ir(NHC)Cl]+, Related to a Water-Oxidation Catalyst

The structure, electrochemical characterization, and EPR spectroscopy of an iridium precatalyst, which is a precursor to a catalyst that can oxidize water to dioxygen, is described in this publication from the Crabtree group (Yale University). The results support previous studies of Cp*Ir catalysts and provide further knowledge of the electrochemical behavior of these water-oxidation catalysts.

Group Picture from CCHF Summer School and Annual Meeting

group photo 2011

June 6, 2011 — The 2nd Annual Meeting of the CCHF took place on June 1-3 in Charlottesville VA. The first day was a Summer School followed by two days of research presentations including a poster session.

PDF document icon CCHF Poster from EFRC Summit and Forum (.pdf, 1.3MB)

May 24, 2011 — The CCHF presented a Center overview poster at the EFRC Summit and Forum in Washington, DC.

ACS Voices of Research Video features CCHF

April 22, 2011 — The American Chemical Society, Office of Public Affairs produces a video series that highlights researchers working on today’s most cutting-edge scientific challenges called Voices of Research. The CCHF was filmed for one of the three minutes videos that focus on how fundamental research can impact everyday life. Use the link above to view the video.

Robert H. Crabtree Elected to the American Academy of Arts and Sciences

April 19, 2011 — Some of the world’s most accomplished leaders from academia, business, public affairs, the humanities, and the arts have been elected members of the American Academy of Arts and Sciences. 

A list of the new Academy members announced today is located at:

PDF document icon http://www.amacad.org/news/alphalist2011.pdf (.pdf). 

The 212 new members join one of the nation’s most prestigious honorary societies and a leading center for independent policy research. Members contribute to Academy studies of science and technology policy, global security, social policy and American institutions, the humanities, and education. 

Strem Chemicals, Inc. to Sponsor ACS Symposium

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April 8, 2011 — Strem Chemicals, Inc. will sponsor the Frontiers in C-H Activation and Functionalization Symposium at the 242nd ACS Meeting in Denver, CO in August. For a complete list of speakers and sponsors, PDF document icon click here (.pdf, 224KB).

The Dow Chemical Company to Sponsor ACS Symposium

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April 7, 2011 — The Dow Chemical Company will sponsor the Frontiers in C-H Activation and Functionalization Symposium at the 242nd ACS Meeting in Denver, CO in August. For a complete list of speakers and sponsors, PDF document icon click here (.pdf, 224KB).

Chevron Corporation to Sponsor ACS Symposium

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April 4, 2011 — Chevron Corporation will sponsor the Frontiers in C-H Activation and Functionalization Symposium at the 242nd ACS Meeting in Denver, CO in August. For a complete list of speakers and sponsors, PDF document icon click here (.pdf, 224KB).

Local News Highlights Research at UNT

March 28, 2011 — Kurtis Carsch, a student in Tom Cundari's group at the University of North Texas was featured on the local news.

PDF document icon CCHF Talks at 2011 Spring ACS National Meeting (.pdf, 152KB)

March 27-31, 2011 — CCHF faculty will present multiple talks at the meeting in Anaheim.

Interfacial Electron Transfer Dynamics Following Laser Flash Photolysis of [Ru(bpy)2((4,4'-PO3H2)2bpy)]2+ in TiO2 Nanoparticle Films in Aqueous Environments

February 16, 2011 — In a new publication from the Meyer group (University of North Carolina, Chapel Hill), nanosecond laser flash photolysis has been used to investigate injection and back electron transfer from the complex [(Ru(bpy)2(4,4'-(PO3H2)2bpy)]2+ surface-bound to TiO2. The measurements were conducted under conditions appropriate for water oxidation catalysis by known single-site water oxidation catalysts. Systematic variations in average lifetimes for back electron transfer, <τbet>, were observed with changes in pH, surface coverage, incident excitation intensity, and applied bias. The results were qualitatively consistent with a model involving rate-limiting thermal activation of injected electrons from trap sites to the conduction band or shallow trap sites followed by site-to-site hopping and interfacial electron transfer, TiO2(e−)-Ru3+→TiO2-Ru2+. 

An Iridium(IV) Species, [Cp*Ir(NHC)Cl]+, Related to a Water-Oxidation Catalyst

February 8, 2011 — The Ir precatalyst developed by the Crabtree group (Yale University) contains both a Cp* and a chelating NHC. Like their other recently described Cp*Ir catalysts, this compound is a precursor to a catalyst that can oxidize water to dioxygen. Electrochemical characterization of the new compound shows that it has a stable iridium(IV) oxidation state.

Vigor Gloveboxes to Sponsor ACS Symposium

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February 1, 2011 — Vigor Gloveboxes will sponsor the Frontiers in C-H Activation and Functionalization Symposium at the 242nd ACS Meeting in Denver, CO in August. For a complete list of speakers and sponsors, PDF document icon click here (.pdf, 224KB).

Multiple Pathways for Benzyl Alcohol Oxidation by RuV═O3+ and RuIV═O2+

January 20, 2011 — Significant rate enhancements were found for benzyl alcohol oxidation when the ruthenium water oxidation catalyst was in the +5 oxidation state. This publication by the Meyer group (UNC, Chapel Hill) also describes a new pathway, concerted hydride proton transfer (HPT).

Mechanism of Efficient Anti-Markovnikov Olefin Hydroarylation Catalyzed by Homogeneous Ir(III) Complexes

January 17, 2011 — The mechanism of the hydroarylation reaction between unactivated olefins (ethylene, propylene, and styrene) and benzene catalyzed by Ir(III) complexes was studied with experimental methods by the Periana (The Scripps Research Institute, Florida) and Goddard (Caltech) groups. The system is selective for generating the anti-Markovnikov product of linear alkylarenes. The reaction mechanism was found to follow a rate law with first-order dependence on benzene and catalyst, but a non-linear dependence on olefin. 

Catalytic Oxy-Functionalization of Methane and Other Hydrocarbons: Fundamental Advancements and New Strategies

ChemSusChem Cover

January 17, 2011 — The cover image of the January 2011 issue showcases the research of Joanna Webb, Tamara Bolaño, and Brent Gunnoe (University of Virginia). Their Minireview outlines strategies towards the catalytic oxy-functionalization of methane and other hydrocarbons. The development of a catalyst for the controlled conversion of methane to methanol (MTM) would result in a paradigm shift for the chemical industry.

Synthesis, Characterization, and C–H Activation Reactions of Novel Organometallic O-donor Ligated Rh(III) Complexes

January 15, 2011 — The synthesis and characterization of the O-donor ligated, air and water stable rhodium complexes are reported. These compounds are analogues to the O-donor iridium complexes that are active catalysts for the hydroarylation and C–H activation reactions as well as the bis-acetylacetonato rhodium complexes, which we recently reported. The rhodium complex undergoes a quantitative trans to cis isomerization in cyclohexane to form a new complex, which activates C–H bonds in both benzene and mesitylene. All of these compounds are air and water stable and do not lead to decomposition products.

An Organometallic Future in Green and Energy Chemistry?

January 4, 2011 — The title topic is reviewed by Robert H. Crabtree (Yale University) with selected examples taken from recent work, such as: the 'hydrogen borrowing' amine alkylation by alcohols; the dehydrogenative coupling of amine and alcohol to give amide; Ru complexes as solar cell photosensitizers; Ir organometallics as water oxidation catalyst precursors and as OLED emitters; as well as recent hydrogen storage strategies involving catalytic dehydrogenation of ammonia-borane and of organic heterocycles.

Multifunctional Ligands in Transition Metal Catalysis

NJC cover

December 21, 2010 — Sophisticated ligands are now being designed that do far more than just fulfill their traditional spectator roles by binding to the metal and providing a sterically-defined binding pocket for the substrate in homogeneous transition metal catalysis. This Focusreview by Robert H. Crabtree (Yale University) emphasizes selected cases in which ligands carry additional functional groups that change the properties of the ligand as a result of an external stimulus or undergo catalytically-relevant ligand-based reactivity.

Ligand Lone-Pair Influence on Hydrocarbon C−H Activation: A Computational Perspective

December 3, 2010 — A joint publication from the Ess, Gunnoe, Cundari, Goddard, and Periana groups recently appeared in Organometallics. This computational paper describes mid to late transition metal complexes that break hydrocarbon C−H bonds by transferring the hydrogen to a heteroatom ligand while forming a metal−alkyl bond offer a promising strategy for C−H activation.

Chemistry in the Center for Catalytic Hydrocarbon Functionalization: An Energy Frontier Research Center

December 2, 2010 — A perspective article describing the research in the CCHF written by the management committee recently appeared in Catalysis Letters.

Nonaqueous Catalytic Water Oxidation

November 23, 2010 — The Meyer group (University of North Carolina, Chapel Hill) has recently published a communication in the Journal of the American Chemical Society reporting ruthenium complexes on oxide electrodes that are water oxidation catalysts in propylene carbonate and 2,2,2-trifluoroethanol (TFE) to which water has been added as a limiting reagent. The rate of water oxidation is greatly enhanced relative to that with water as the solvent and occurs by a pathway that is first-order in water; an additional pathway that is first-order in acetate appears when TFE is used as the solvent.

Rhodium complexes bearing tetradentate diamine-bis(phenolate) ligands

November 11, 2010 — A joint publication from the Goddard (Caltech) and Periana (Scripps) groups discloses rhodium complexes for C-H activation. Using tetradentate, dianionic ligands, several new rhodium complexes have been prepared. Some of these diamine-bis(phenolate) compounds, are active for C–H activation of benzene. These complexes are air and thermally stable. All four complexes were characterized by X-ray diffraction.

Electrophilic, Ambiphilic, and Nucleophilic C−H Bond Activation: Understanding the Electronic Continuum of C−H Bond Activation Through Transition-State and Reaction Pathway Interaction Energy Decompositions

November 1, 2010 — The potential energy and interaction energy profiles for metal- and metal−ligand-mediated alkane C−H bond activation were explored using B3LYP density functional theory (DFT) and the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) by Ess (Brigham Young University), Goddard (Caltech), and Periana (Scripps) in a recent article in Organometallics. Quantitative analysis using ALMO-EDA of both directions of charge-transfer stabilization (occupied to unoccupied orbital stabilization) energies between the metal−ligand fragment and the coordinated C−H bond in the transition state for cleavage of the C−H bond allows classification of C−H activation reactions as electrophilic, ambiphilic, or nucleophilic on the basis of the net direction of charge-transfer energy stabilization. As a qualitative approximation, investigation of transition-state fragment orbital energies showed that relative frontier orbital energy gaps correctly reflect electrophilic, ambiphilic, or nucleophilic charge-transfer stabilization patterns.

ReaxFF Monte Carlo reactive dynamics:  Application to resolving the partial occupations of the M1 phase of the MoVNbTeO catalyst

November 1, 2010 — A new publication from the Goddard (Caltech) group in Catalysis Today describes how they have developed the ReaxFF-MC-RD computational approach to resolve such partial occupations of crystallographic sites, which were used to determine the atomistic arrangements in the M1 phase of the MoVNbTeO system.

Recent Periana Communication Highlighted in Science by Crabtree

October 22, 2010 — Bob Crabtree (Yale University) contributed a perspectives article to the most recent issue of Science. The article describes Periana's recent JACS communication in the context of ligands that respond to the reaction media in order to tune complex reactivity.

PDF document icon First Issue of Focus on Catalysis (.pdf, 834KB)

October 18, 2010 — The CCHF is pleased to publish the first issue of its newsletter, Focus on Catalysis. The newsletter highlights meetings, recent publications from the CCHF, and other news items of interest to the CCHF community.

Manganese Porphyrins Catalyze Selective C−H Bond Halogenations

August 31, 2010 — A new publication in the Journal of the American Chemical Society from the Groves group (Princeton University) reports a manganese porphyrin mediated aliphatic C−H bond chlorination using sodium hypochlorite as the chlorine source.

Acceleration of Nucleophilic C-H Activation by Strongly Basic Solvents

August 24, 2010 — A new publication in the Journal of the American Chemical Society from the Periana group (The Scripps Research Institute, Florida) describes a ruthenium complex that can catalyze H/D exchange between hydrocarbons and strongly basic solvents at higher rates than in the case of the solvent alone. Significantly, this catalysis is accelerated rather than inhibited by increasing solvent basicity. 

Cp* Iridium Complexes Give Catalytic Alkane Hydroxylation with Retention of Stereochemistry

August 23, 2010 — A new publication in the Journal of the American Chemical Society from the Crabtree group (Yale University) describes a series of Cp*Ir complexes that can catalyze C-H oxidation, with ceric ammonium nitrate as the terminal oxidant and water as the source of oxygen.

PDF document icon CCHF Researchers to give Presentations and Posters at Fall 2010 ACS Meeting, Boston (.pdf, 163KB)

July 21, 2010 — Use this link to see a list of all talks and posters to be presented by CCHF researchers at the Fall 2010 ACS National Meeting in Boston, MA from August 22 through August 26.

Presentation by Brent Gunnoe (UVa) at Organometallic GRC

July 14, 2010 — Prof. Brent Gunnoe from the University of Virginia presented a talk entitled "Development of New Catalysts for the Functionalization of Hydrocarbons" at the Organometallic Gordon Research Conference in Newport, RI.

Presentation by Jay Groves (Princeton) at International Conference on Porphyrins and Phthalocyanines

July 9, 2010 — Prof. Jay Groves presented the Hans Fischer Award address at the meeting of the International Conference on Porphyrins and Phthalocyanines in Santa Ana Pueblo, NM. The award is sponsored by the Hans Fischer Gesellschaft of Munich. Jay spoke about his work with metal-oxo complexes and C-H bond oxygenation to an audience of 500 attendees.

Catalytic Water Oxidation on Derivatized nanoITO

June 30, 2010 — New publication in Dalton Transactions from the Meyer group at the University of North Carolina, Chapel Hill.

Presentation by Jonathan Hull (UNC-CH) at Inorganic GRC

June 20, 2010 — Dr. Jonathan Hull from the Meyer group at the University of North Carolina, Chapel Hill presented a poster entitled "C-H Bond Oxidations using Ruthenium Complexes: Transferring Reactivity from Solution to Electrode Surface" at the Inorganic Chemistry Gordon Research Conference in Biddeford, ME.

Presentation by Jay Groves (Princeton) at the ACS Maryland Section Meeting

June 16, 2010 — Prof. Jay Groves presented the Ira Remsen Award address at the meeting of the American Chemical Society Maryland Section at Johns Hopkins University. The Remsen Award, which can be in any field, has been given annually by the ACS since 1946. Jay spoke about his work with metal-oxo complexes and C-H bond oxygenation. 

CCHF Director Presents at DOE Catalysis Science Meeting

June 5, 2010 — Prof. Brent Gunnoe, Director of the Center, presented a talk describing the ongoing research in the Center at the DOE meeting in Annapolis, MD.

First Annual Meeting of the Center for Catalytic Hydrocarbon Functionalization was Success

May 28, 2010 — Over forty researchers attended the meeting in Charlottesville, VA. Presentations were given by seven professors, six postdoctoral scholars, and two graduate students. Keynote addresses were presented by Prof. Alan Goldman, Dr. Dan Dubois, and Prof. Dean Harman. Posters were presented by researchers in the Center and associated research groups at the University of Virginia.

First Annual Meeting of the Center for Catalytic Hydrocarbon Functionalization

March 31, 2010 — The first annual meeting of the Center for Catalytic Hydrocarbon Functionalization will be held on May 27 and 28 at the University of Virginia in Charlottesville, VA. The two-day meeting will feature presentations from CCHF senior personnel, graduate students and postdoctoral researchers. In addition, we are pleased to announce that Professor Alan Goldman (Rutgers University) and Dr. Daniel Dubois (Pacific Northwest National Laboratory) will deliver research presentations.

 

Department of Energy announces awards for new Energy Frontier Research Centers

August 6, 2009

“Washington, DC – In a major effort to accelerate the scientific breakthroughs needed to build a new 21st-century energy economy, U.S. Energy Secretary Steven Chu announced the delivery of $377 million in funding for 46 new multi-million-dollar Energy Frontier Research Centers (EFRCs) located at universities, national laboratories, nonprofit organizations, and private firms across the nation.…”

Read more at energy.gov