•Schiff-base pre-assembly versus one-pot synthesis give different Ni(II) complexes.•Ni(II) complexes identified by IR, UV–VIS, elemental analysis and X-ray diffraction.•Select Ni(II) complexes fully inhibit growth of pathogenic yeast Candida albicans.

done Most notable is the conversion of methane to methyl bisulfate in the presence of a platinum catalyst. The reaction is carried out in 100% sulfuric acid using SO 3 as et al. 1998). In similar work, methane undergoes direct partial oxidation using iodate salts with catalytic amounts of chloride in protic solvents. In HTFA (where TFA is trifluoroacetate), greater than 20% methane conversion with more than 85% selectivity for MeTFA were achieved (Fortman et al. 2014). Work is continuing for closing trapped in the cross channels of the pores. The currently accepted mechanism is referred to as the hydrocarbon pool (HCP) mechanism. If not supplied with sufficient additional methanol (or DME), the HMB eventually leads to coke formation. At reaction temperatures below 250 °C, no methanol conversion is observed. Only methanol and dimethyl ether appear in the effluents. There is a fast deactivation of the catalyst at lower temperatures with the appearance of light olefins and other hydrocarbons in the temperature of 300−325 °C. The yield of hydrocarbon products catalytically to produce drop-in and and methoxymethyl-furfural) that can then upgraded precursors converted into distillate-range hydrocarbons through hydrogenation, condensation, and hydrodeoxygenation. ) acids can converted through converted hydrocarbon fuel ketonization, aldol condensation, and oxides of the spinel or perovskite structure, such as Co 3 O 4 that exhibit overpotentials of ~350 mV at a current density of 10 mA/cm 2 in 1.0 M KOH, have shown the most success (Esswein et al. 2009). A Ni foam ionomer-impregnated Ni-Fe cathode, which exhibited ~0.35 V overpotential at 400 mA/cm 2 in 1.0 M KOH solution at 40 °C, displayed even better OER performance (Xiao et al. 2012). Other catalysts, such as the recently developed ultrathin Ni-Fe layered double hydroxide (NiFe-LDH) nanoplates on mildly oxidized multiwalled CNTs (Gong et al. 2013), are difficult to compare directly to AEM electrolyzers, since the catalyst loading, catalyst morphology, interaction between catalyst and AEM ionomer, and mass transport challenges in ionomer-impregnated anodes are not present in model systems (Shen

ADVERTISEMENT RETURN TO ISSUEEditor's PageNEXTUndergraduate Research: Contributions to Organometallic ChemistryChristopher A. Bradley*Christopher A. BradleyDepartment of Science, Mount St. Mary’s University, Emmitsburg, Maryland 21727, United States*E-mail: [email protected]More by Christopher A. Bradley and Chip NataroChip NataroDepartment of Chemistry, Lafayette College, Easton, Pennsylvania 18042, United StatesMore by Chip NataroCite this: Organometallics 2018, 37, 12, 1813–1816Publication Date (Web):June 11, 2018Publication History Published online11 June 2018Published inissue 25 June 2018https://doi.org/10.1021/acs.organomet.8b00369Copyright © 2018 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1671Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (221 KB) Get e-AlertsSUBJECTS:Catalytic reactions,Ligands,Students,Transfer reactions,Undergraduates Get e-Alerts

Energy technologies affect virtually every aspect of life in modern societies—including transportation, utilities, agriculture, medicine, and the availability of a myriad of consumer products—and depend on human ability to accelerate and to guide chemical transformations. Controlling these transformations, which occur in the microscopic world of atoms and molecules, forms the basis of countless technologies such as production of fuels, fertilizers, plastics, pharmaceuticals and much more. At the very core of these chemical transformations are catalysts—specialized and often highly complex types of matter that allow chemical reactions to occur rapidly and produce specific products. Catalysts also have the remarkable ability to perform their tasks millions of times without themselves being consumed. The discovery of inexpensive and widely-deployable energy and chemical technologies, and their underpinning catalysis science, is critical to ensure the economic viability of US energy and chemical industries. Over the past decade, remarkable new tools have been discovered that allow the observation of catalytic transformations in exquisite detail, and assembly of novel and elaborate catalytic architectures with atomic precision. Furthermore, increasingly sophisticated theoretical and computational tools allow understanding of the essential details of the catalytic processes, and this overall progress has led to the discovery of catalysts with superior performance more»

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that derive from initial 2-bromo-2-butene lithiation followed by acid mediated dienol cyclization. The revised synthesis and purification of the ligand avoids the use of mechanical stirring while still permitting access to significant quantities (39 g) of Cp*H in good yield (58%). The procedure offers other additional benefits, including a more controlled quench of excess lithium during the production of the intermediate heptadienols and a simplified isolation of Cp*H of sufficient purity for metallation with transition metals. The ligand was subsequently used to synthesize [Cp*MCl2]2 complexes of both iridium and ruthenium to demonstrate the utility of the Cp*H prepared and purified by our method. The procedure outlined herein affords substantial quantities of a ubiquitous ancillary ligand support used in organometallic chemistry while minimizing the need for specialized laboratory equipment, thus providing a simpler and more accessible entry point into the chemistry of 1,2,3,4,5-pentamethylcyclopentadiene.

Energy technologies affect virtually every aspect of life in modern societies—including transportation, utilities, agriculture, medicine, and the availability of a myriad of consumer products—and depend on human ability to accelerate and to guide chemical transformations. Controlling these transformations, which occur in the microscopic world of atoms and molecules, forms the basis of countless technologies such as production of fuels, fertilizers, plastics, pharmaceuticals and much more. At the very core of these chemical transformations are catalysts—specialized and often highly complex types of matter that allow chemical reactions to occur rapidly and produce specific products. Catalysts also have the remarkable ability to perform their tasks millions of times without themselves being consumed. The discovery of inexpensive and widely-deployable energy and chemical technologies, and their underpinning catalysis science, is critical to ensure the economic viability of U.S. energy and chemical industries. Over the past decade, remarkable new tools have been discovered that allow the observation of catalytic transformations in exquisite detail, and assembly of novel and elaborate catalytic architectures with atomic precision. Furthermore, increasingly sophisticated theoretical and computational tools allow understanding of the essential details of the catalytic processes, and this overall progress has led to the discovery of catalysts with superior performance and the associated economic benefit. In the next decade and beyond, science promises to revolutionize how catalysts and catalytic processes are designed, to enable the introduction of new energy resources, to provide routes to sustainable synthesis of chemicals and other valuable materials, and to create novel approaches to chemical energy storage. This report is the result of the Basic Energy Sciences Workshop on Basic Research Needs for Catalysis Science to Transform Energy Technologies that was held in May 2017, and was attended by more than 100 leading national and international scientific experts. The attendees were organized into four panels: 1. Diversified Energy Feedstocks and Carriers, 2. Novel Approaches to Energy Transformations, 3. Advanced Chemical Conversion Approaches, and 4. Crosscutting Capabilities and Challenges: Synthesis, Theory, and Characterization. The workshop identified five priority research directions (PRDs) that are aimed at harnessing complexity in catalysis to create next-generation energy technologies and realizing efficient catalytic processes to increase the diversity of resources for production of chemicals and energy.

Synthesis of a series of sterically expanded arenes, containing one or more 1,2,3,4-tetrahydro-1,1,4,4-tetramethyl substituents, was accomplished in high yield utilizing classic Friedel–Crafts alkylation conditions. Metallation of these arenes with molybdenum was accomplished via reflux of Mo(CO)6 in a mixed solvent combination in the presence of the ligand. The (η6-arene)Mo(CO)3 complexes were isolated in reasonable yields (45–60%) and characterized through a combination of 1H and 13C NMR spectroscopy, X-ray crystallography, IR spectroscopy, elemental analysis, and mass spectrometry. The crystallographic data reveal the ability to tune the steric profile of the arene through judicious ligand choice. Ligand electronics can also be modified to some degree, though to a lesser extent than the steric congestion about the metal center. Computational analysis of the arene complexes corroborate the observed trend of increasing electron donation by the arene as the steric bulk increases. Reactivity of selected Mo complexes highlight the dramatic change in stability substitution imparts on the compounds, as the least sterically congested complex undergoes fastest arene exchange while the bulkiest ligand results in a compound indefinitely stable in neat arene under identical conditions. Attempts at determining whether this substitution chemistry is driven by thermodynamic or kinetic factors were explored computationally and align with systems that have been examined previously. These studies introduce a family of tunable, sterically congested arene ligands that may find value as new supports in the preparation of a range of metal–arene complexes.

Synthesis of coordinatively unsaturated Cp*Co(IPr) (2), is accomplished by addition of free N-heterocyclic carbene IPr to [(Cp*Co)2-μ-(η(4):η(4)-toluene)] (1). Stoichiometric reactivity is consistent with a 16 electron species, as 2 undergoes ligand addition/NHC displacement and reversible reaction with dihydrogen. Cp*Co(IPr) represents an elusive example of a stable Cp*CoL fragment.

Alkali metal reduction of (η(5)-C9H5-1,3-(SiMe3)2)2Co (1) in tetrahydrofuran (THF) permits isolation of the unusual and reactive 20 electron Co(I) anion [Na(THF)6][(η(5)-C9H5-1,3-(SiMe3)2)2Co] (2). Crystallographic characterization of both 1 and 2 provide support for the one electron reduction from Co(II) to Co(I). Reactivity studies of 2 are further consistent with a Co(I) equivalent, based on both one electron chemical oxidation to reform 1 and reaction with a variety of σ and π donors. Upon addition of pyridines or vinyltrimethylsilane to 2, known dimer [(C9H5-1,3-(SiMe3)2)2Co2] (3) is formed, likely through 16 electron (η(5)-C9H5-1,3-(SiMe3)2)Co(L) intermediates. Ethylene addition to 2 establishes an equilibrium between (η(5)-C9H5-1,3-(SiMe3)2)Co(η(2)-H2C═CH2)2 (8) and 2, suggestive of reversible ligand ejection from 2. Crossover experiments between a related metal indenide salt and 2 confirm ligand extrusion from the anion, even in the absence of strong supporting donors. Reaction of 2 with PMe3 results in formation of 3, (η(5)-C9H5-1,3-(SiMe3)2)Co(PMe3)2 (13), and a paramagnetic species, with the product ratios being highly dependent on the conditions of synthesis. Collectively, 2 demonstrates an alternative entry point into the chemistry of 14 electron Co(I) equivalents when compared to typical ligand loss from neutral 18 electron cyclopentadienyl cobalt bis(ligand) complexes, perhaps permitting generation of low electron count species more effective for small molecule activation.

AbstractCatalytic transfer dehydrogenation of silyl‐protected amines is achieved under mild conditions using the title bridging cobalt arene complex.

The preparation of terminally functionalized atactic polypropylenes is described. Using standard organic transformations, an olefin terminated polypropylene oligomer could be converted into many other important functional groups. Such species can serve as useful polymer-bound building blocks for synthesis and catalysis. These supported derivatives exhibit high phase-selective solubility in nonpolar solvents, making them excellent candidates for use as supported reagents/catalysts.

The synthesis of the sterically hindered 1,3,4,7-tetrasubstituted indenyl ligand 1,3-(CHMe2)(2)-4,7-Me-2-C9H3 is accomplished via initial preparation of 4,7-dimethylindene and subsequent installation of isopropyl groups on the five-membered ring. Synthesis of the corresponding bis(indenyl) iron complex (eta(5)-C9H3-1,3-(CHMe2)(2)-4,7-Me-2)(2)Fe (3) and comparison to a bis(indenyl) iron analogue devoid of benzo substituents, (eta(5)-C9H5-1,3-(CHMe2)(2))(2)Fe (4), through variable-temperature NMR studies and electrochemistry, establishes the new ligand as both more sterically demanding and slightly more electron rich. Alkali-metal reduction of (eta(5)-C9H3-1,3-(CHMe2)2-4,7-Me-2)(2)ZrCl2 (5) yields an equilibrium mixture of the eta(5),eta(9) sandwich complex 7 and the cyclometalated hydride 8, indicating both that benzo binding is still possible when the six-membered ring is substituted and that ligand activation can be modulated by the choice of substituents, as the eta(5),eta(9) zirconium sandwich 9, which lacks methyl groups on the benzo ring, does not cyclometalate under ambient conditions. The reactivity of 8 was explored, demonstrating that the cyclometalated species can act as a source of both Zr(II), via ligand-induced reductive elimination, and Zr(IV), through insertion or sigma bond metathesis, depending on the added reagent. Addition of H-2 to 8 gives (eta(5)-C9H3-1,3-(CHMe2)(2)-4,7-Me-2)(2)ZrH2 (17), which upon prolonged thermolysis results in benzo C=C bond insertion into the Zr hydride. The reaction rate in comparison to that of the bis(indenyl) zirconium dihydride analogue 19, without benzo substituents, suggests that the methyl groups on the six-membered ring significantly reduce the rate of intramolecular insertion. These studies show that benzo substitution accomplishes both major intended goals: destabilizing the interaction of the benzo ring with low-valent metals while reducing the rate of insertion of a benzo C=C bond into a metal hydride in high-oxidation-state complexes.

The well-defined oxidative addition of the vinylic sp(2) C-H bond of dimethyl fumarate is mediated by the cobalt triple decker complex [(Cp*Co)(2)-μ-(η(4) : η(4)-toluene)] (1) at ambient temperature, affording the dinuclear, bridging cobalt hydride, fumaryl compound (2). The C-H activation product has been characterized by mass spectrometry, NMR spectroscopy, and X-ray crystallography. Computational studies of 2 support asymmetric bonding interactions between the two metal centres and the bridging hydride/fumaryl fragments. Monitoring the reaction of dimethyl fumarate with 1 by (1)H NMR spectroscopy allows observation of intermediate [Cp*Co(MeO(2)CCH=CHCO(2)Me)](n) (n = 1 or 2) (3). Addition of 4 equivalents of dimethyl fumarate to 1 results in rapid formation of the bis(ligand) adduct Cp*Co(η(2)-MeO(2)CCH=CHCO(2)Me)(2) (5). Reversibility of the C-H activation was probed by reaction of additional dimethyl fumarate with 2, suggesting ligand induced reductive elimination is possible under ambient conditions. Reaction between 2 and strong σ or π ligands, such as PMe(3) or CO, affords the corresponding Cp*Co(η(2)-MeO(2)CCH=CHCO(2)Me)(L) (L = PMe(3) (7); L = CO (8)) complexes when heated, demonstrating the ability of 2 to undergo two electron redox processes. Further evidence for reversible C-H activation is provided by the isomerization of dimethyl maleate to the corresponding fumarate using 2, suggesting the complex can serve as a source of Co(I) under the appropriate catalytic conditions.