A5089408235- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Crystallography and molecular interactions
- Metalloenzymes and iron-sulfur proteins
- Magnetism in coordination complexes
- Metal-Organic Frameworks: Synthesis and Applications
- Organometallic Complex Synthesis and Catalysis
- Electrocatalysts for Energy Conversion
- Metal-Catalyzed Oxygenation Mechanisms
- Metal complexes synthesis and properties
- Asymmetric Hydrogenation and Catalysis
- Porphyrin and Phthalocyanine Chemistry
- Iron-based superconductors research
- Lanthanide and Transition Metal Complexes
- Molecular Junctions and Nanostructures
- CO2 Reduction Techniques and Catalysts
- 2D Materials and Applications
- Organic and Molecular Conductors Research
- Carbon dioxide utilization in catalysis
- Inorganic Fluorides and Related Compounds
- Advanced Condensed Matter Physics
- Conducting polymers and applications
- Oxidative Organic Chemistry Reactions
- Crystal Structures and Properties
- Nuclear materials and radiation effects
University of Illinois Urbana-Champaign
2016-2025
Urbana University
2018-2021
Texas A&M University
2015-2019
College Station Medical Center
2015-2019
University of Illinois System
2018
Eastern Washington University
2012-2016
Mitchell Institute
2015
The selective hydrogenation of nitriles to primary amines using a bench-stable cobalt precatalyst under 4 atm H2 is reported herein. catalyst precursor was reduced in situ NaHBEt3, and the resulting Lewis acid formed, BEt3, found be integral observed catalysis. Mechanistic insights gleaned from para-hydrogen induced polarization (PHIP) transfer NMR studies revealed that pairwise proceeded through Co(I/III) redox process.
A family of isostructural, mononuclear CoII complexes with distorted trigonal bipyramidal coordination environments is reported. The degree distortion as well the overall symmetry molecules varies among members series. Different experimental procedures resulted in isolation solvomorphs (pseudopolymorphs different solvent content) for some members. Importantly, their disparate packing arrangements lead to very dynamic magnetic behavior. results magnetostructural correlations and ab initio...
Shear selectivity Chemical reactions typically proceed by distributing energy statistically among all accessible molecular vibrations. Liu et al. report that external shear forces can sometimes pry open strained carbon rings without dissipating into adjacent bond rotations. Through careful design and synthesis of polymer-embedded cyclobutyl rings, the authors showed certain relative substituent geometries are preserved when sonication induces ring opening. Accompanying simulations support...
Advances in genome sequencing and bioinformatics methods have identified a myriad of biosynthetic gene clusters (BGCs) encoding uncharacterized molecules. By mining genomes for BGCs containing prevalent peptide-binding domain used the biosynthesis ribosomally synthesized post-translationally modified peptides (RiPPs), we uncovered new compound class involving modifications installed by cytochrome P450, multinuclear iron-dependent non-heme oxidative enzyme (MNIO, formerly DUF692), cobalamin- radical
We investigate an approach to tune the d-band center and enhance oxygen reduction reaction (ORR) activity of Pt material without relying on foreign metals or process alloying/dealloying. It is known that exhibits suboptimal ORR catalytic due its strong binding oxygen, therefore requiring a downshift in by approximately 0.2 eV weaken Pt-O energy boost kinetics. found can be tuned inducing microstrain electrodeposit, simply achieved introducing polymer into electrodeposition bath. electrodes...
Like silicon, single crystals of organic semiconductors are pursued to attain intrinsic charge transport properties. However, they intolerant mechanical deformation, impeding their application in flexible electronic devices. Such contradictory properties, namely exceptional molecular ordering and flexibility, unified this work. We found that bis(triisopropylsilylethynyl)pentacene (TIPS-P) can undergo mechanically induced structural transitions exhibit superelasticity ferroelasticity. These...
Oxygen evolution reaction (OER) takes place in various types of electrochemical devices that are pivotal for the conversion and storage renewable energy. This paper describes a strategy design solid-state structures OER electrocatalysts through controlling cation substitution on active metal site consequently valence band center position site-mixed Y2(YxRu1–x)2O7−δ pyrochlore to achieve high catalytic activity. We found partially replacing B-site Ru4+ with A-site Y3+ pyrochlore-structured...
A spin-crossover conductor with partially charged TCNQ exhibits a high room temperature conductivity and an anomaly in conductivity.
We report the oxygen reduction reaction (ORR) activity in acid of an Fe porphyrin on different supports. While is high (E1/2 = 0.34 V vs RHE with n 3.8) when adsorbed XC72 (a graphitic carbon), this much lower either MoS2 −0.15 2.2) or g-C3N4 −0.24 3.1). Electron paramagnetic resonance (EPR), X-ray absorption fine structure (XAFS), and magnetometry measurements show electronic around center same for all three Only supported exhibits a pH dependence its ORR activity. This observation, coupled...
The biosynthesis of the active site [FeFe]-hydrogenases (HydA1), H-cluster, is interest because these enzymes are highly efficient catalysts for oxidation and production H2. [2Fe]H subcluster H-cluster proceeds from simple precursors, which processed by three maturases: HydG, HydE, HydF. Previous studies established that HydG produces an Fe(CO)2(CN) adduct cysteine, substrate HydE. In this work, we show using synthetic cluster [Fe2(μ-SH)2(CN)2(CO)4]2– HydA1 can be biosynthesized without maturases
The ligand-centered radical complex [(CoTPMA)2 -μ-bmtz(.-) ](O3 SCF3 )3 ⋅CH3 CN (bmtz=3,6-bis(2'-pyrimidyl)-1,2,4,5-tetrazine, TPMA=tris-(2-pyridylmethyl)amine) has been synthesized from the neutral bmtz precursor. Single-crystal X-ray diffraction studies have confirmed presence of radical. Co(II) exhibits slow paramagnetic relaxation in an applied DC field with a barrier to spin reversal 39 K. This behavior is result strong antiferromagnetic metal-radical coupling combined positive axial...
In the dynamic synthesis of covalent organic frameworks and molecular cages, typical synthetic approach involves heuristic methods discovery. While this has yielded many remarkable products, ability to predict structural outcome subjecting a multitopic precursor chemistry (DCC) remains challenge in field. The cages is prime example phenomenon, where precursors designed with intention affording specific product may deviate dramatically when DCC attempted. As such, rational design principles...
Mononuclear monodioxolene valence tautomeric (VT) cobalt complexes typically exist in their low spin (l.s.) Co
When only poorly diffracting crystals are available, it is often necessary to truncate the resolution of final integration. What limit choose for integration a gray area. There numerous statistics that can be examined aid in deciding where transition from weak data noise occurs. In this presentation, we will examine pair and try decide at what should terminated.
The radical bridged compound [(Ni(TPMA))2-μ-bmtz•–](BF4)3·3CH3CN (bmtz = 3,6-bis(2′-pyrimidyl)-1,2,4,5-tetrazine, TPMA tris(2-pyridylmethyl)amine) exhibits strong ferromagnetic exchange between the S 1 NiII centers and bridging 1/2 bmtz with J 96 ± 5 cm–1 (−2JNi-radSNiSrad). DFT calculations support existence of exchange.
Bifunctional electrically conducting single-molecule magnets are highly promising platforms for non-volatile memory devices and quantum computing applications. The development of these molecular materials, however, has largely been hindered by the lack straightforward synthetic methods. Herein a facile modular approach is demonstrated realization bifunctional materials that does not require electrochemical or chemical oxidation to obtain partially charged organic radicals. Magnetic...
The crystal structures of NiX2(pyz)2 (X = Cl (1), Br (2), I (3), and NCS (4)) were determined by synchrotron X-ray powder diffraction. All four compounds consist two-dimensional (2D) square arrays self-assembled from octahedral NiN4X2 units that are bridged pyz ligands. 2D layered motifs displayed 1–4 relevant to bifluoride-bridged [Ni(HF2)(pyz)2]EF6 (E P, Sb), which also possess the same layers. In contrast, terminal X ligands occupy axial positions in cause a staggered packing adjacent...
Described is the preparation of first iron carbide-sulfides. The cluster [Fe6C(CO)15(SO2)]2- ([2]2-), which generated quantitatively from [Fe6C(CO)16]2- ([1]2-), was O-methylated to give sulfinite [2Me]-. Demethoxylation [2Me]- with BF3 gave face-capped octahedral Fe6C(CO)15(SO) (3). In solution, 3 spontaneously converted sulfide Fe6C(CO)16(S) (4), an edge-fused double Fe5C and Fe3S subunits. Although 4 undergoes 1e- reduction reversibly, 2e- (or base hydrolysis) gives...
The synthesis and redox properties are presented for the electron-rich bis(monothiolate)s Fe2(SR)2(CO)2(dppv)2 R = Me ([1]0), Ph ([2]0), CH2Ph ([3]0). Whereas related derivatives adopt C2-symmetric Fe2(CO)2P4 cores, [1]0–[3]0 have Cs symmetry resulting from unsymmetrical steric of axial vs equatorial groups. Complexes undergo 1e– oxidation upon treatment with ferrocenium salts to give mixed valence cations [Fe2(SR)2(CO)2(dppv)2]+. As established crystallographically, [3]+ adopts a rotated...
Described are the syntheses of several Ni(μ-SR)2Fe complexes, including hydride derivatives, in a search for improved models active site [NiFe]-hydrogenases. The nickel(II) precursors include (i) nickel with tripodal ligands: Ni(PS3)− and Ni(NS3)− (PS33– = tris(phenyl-2-thiolato)phosphine, NS33– tris(benzyl-2-thiolato)amine), (ii) traditional diphosphine-dithiolates, chiral diphosphine R,R-DIPAMP, (iii) cationic Ni(phosphine-imine/amine) (iv) organonickel Ni(o-tolyl)Cl(tmeda) Ni(C6F5)2....
Seleniferous oxyanions are groundwater contaminants from both anthropogenic and natural sources, while pure amorphous selenium nanoparticles have a variety of industrial applications. Biology can achieve the multicomponent 6 e–/8 H+ reduction selenate to using multiple metalloenzymes, like selenite reductase. Inspired by biology, we developed new homogeneous system that generate elemental with no caustic waste. The stoichiometric reductions selenate, selenite, dioxide an iron(II) complex...