A5037207298- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Crystallography and molecular interactions
- Radioactive element chemistry and processing
- Coordination Chemistry and Organometallics
- Organometallic Complex Synthesis and Catalysis
- Asymmetric Hydrogenation and Catalysis
- Catalysis and Oxidation Reactions
- Catalysis and Hydrodesulfurization Studies
- Catalysis for Biomass Conversion
- Oxidative Organic Chemistry Reactions
- Catalytic Processes in Materials Science
- Synthesis and characterization of novel inorganic/organometallic compounds
- Chemical Thermodynamics and Molecular Structure
- History and advancements in chemistry
- Mesoporous Materials and Catalysis
- Protein Hydrolysis and Bioactive Peptides
- Semiconductor materials and devices
- Advancements in Semiconductor Devices and Circuit Design
- Food composition and properties
- Biofuel production and bioconversion
- Boron Compounds in Chemistry
- Advanced Photocatalysis Techniques
- Synthetic Organic Chemistry Methods
- Electrocatalysts for Energy Conversion
Argonne National Laboratory
2017-2024
University of California, Irvine
2014-2018
Alex's Lemonade Stand Foundation
2017-2018
Biothera (United States)
2010-2015
ProThera Biologics (United States)
2010-2015
Irvine Valley College
2014
University of California System
2014
Structural, spectroscopic, and DFT analysis of the first molecular complexes Th<sup>2+</sup> indicate they have a 6d<sup>2</sup> electron configuration type expected for transactinide ions Rf<sup>2+</sup> Db<sup>3+</sup>.
The reactivity of the recently discovered Th2+ complex [K(18-crown-6)(THF)2][Cp″3Th], 1 [Cp′′ = C5H3(SiMe3)2-1,3], with hydrogen reagents has been investigated and found to provide syntheses new classes thorium hydride compounds. Complex reacts [Et3NH][BPh4] form terminal Th4+ Cp″3ThH, 2, a reaction that formally involves net two-electron reduction. also in solid state solution H2 mixed-valent bimetallic product, [K(18-crown-6)(Et2O)][Cp″2ThH2]2, 3, which was analyzed by X-ray...
The Th3+ complex, (C5Me5)3Th, has been isolated despite the fact that tris(pentamethylcyclopentadienyl) complexes are highly reactive due to steric crowding and few crystallographically characterizable known their reducing nature. Reaction of (C5Me5)2ThMe2 with [Et3NH][BPh4] produces cationic thorium complex [(C5Me5)2ThMe][BPh4] can be treated KC5Me5 generate (C5Me5)3ThMe, 1. methyl group on (C5Me5)3ThMe removed form [(C5Me5)3Th][BPh4], 2, first metal which reduced KC8 yield 3. Complexes 1–3...
An enzymatic method to measure β-glucan content (GEM assay) is applicable in a variety of matrices. The composed swelling the sample with KOH and initial digestion lyticase, which followed by treatment mixture exo-1,3-β-d-glucanase β-glucosidase that converts glucose. glucose generated hydrolysis measured another method. shown be accurate precise. selective both highly branched unbranched β-1,3-glucans.
A well-defined, isolated, single-site organovanadium(iii) catalyst on SiO2 [(SiO2)V(Mes)(THF)] was synthesized via surface organometallic chemistry, and fully characterized using a combination of analytical spectroscopic techniques (EA, ICP, 1H NMR, TGA-MS, EPR, XPS, DR-UV/Vis, UV-Raman, DRIFTS, XAS). The exhibits unprecedented reactivity in liquid- gas-phase alkene/alkyne hydrogenation. Kinetic poisoning experiments revealed that 100% the V sites are active for
Reactions of the 2,2,6,6-tetramethylpiperidin-1-oxyl radical (TEMPO) with thorium metallocenes have been examined to investigate both reaction patterns for organothorium complexes and coordination chemistry TEMPO thorium. (η(5)-C5Me5)2ThMe2 reacts 2 equiv generate 1-methoxy-2,2,6,6-tetramethylpiperidine (Me-TEMPO) (η(5)-C5Me5)2ThMe(η(1)-TEMPO), which contains a TEMPO(-) anion coordinated through oxygen only. (η(5)-C5Me5)2Th(η(1)-C3H5)(η(3)-C3H5), synthesized from (η(5)-C5Me5)2ThBr2...
(C5Me5)2Y(μ-Ph)2BPh2, 1, reacted with ethyllithium at −15 °C to make (C5Me5)2Y(CH2CH3), 2, which is thermally unstable room temperature and formed the C–H bond activation product, (C5Me5)2Y(μ-H)(μ-η1:η5-CH2C5Me4)Y(C5Me5), 3, containing a metalated (C5Me5)1– ligand. Spectroscopic evidence for 2 was obtained low temperature, trapping experiments iPrNCNiPr CO2 gave Y–CH2CH3 insertion products, (C5Me5)2Y[iPrNC(Et)NiPr-κ2N,N′], 4, [(C5Me5)2Y(μ-O2CEt)]2, 5. Although highly reactive, isolation...
Combinatorial screening of 150 supported metal oxide (manganese and additives) catalysts was carried out via a high-throughput synthesis platform parallel reactors for the oxidative dehydrogenation (ODH) propane to propylene. Specifically, an organomanganese (0.05–2.5 Mn atoms/nm2) complex grafted on supports (Al2O3, SiO2, TiO2, ZrO2) premodified with either Lewis acid (Al, Ti, Zn, Zr) or redox-active (Cu, Cr, Ga Ni, V) additives at various surface coverages (25, 50, 75%). Catalysts were...
Understanding the mechanisms of action for base metal catalysis transformations typically associated with precious metals is essential design technologies a sustainable energy economy. Isolated transition-metal and post-transition-metal catalysts on oxides such as silica are generally proposed to effect hydrogenation dehydrogenation by mechanism featuring either σ-bond metathesis or heterolytic bond cleavage key activation step. In this work, an organovanadium(III) complex silica, which...
Scleroglucan is a β-(1,3)-glucan which highly branched at the 6-position with single glucose residue. Acid hydrolysis of high molecular weight scleroglucan gave medium weight, freely soluble material. Linkage analysis by partially methylated alditol acetate method showed that solubilized material had 30% branching. When was subjected to partial Smith degradations, percent branching reduced accordingly 12% or 17%. After reduced, average samples increased considerably, indicating assembly...
Olefin metathesis is a broadly employed reaction with applications that range from fine chemicals to materials and petrochemicals. The design investigation of olefin catalysts have been ongoing for over half century, advancements made in terms activity, stability, selectivity. Immobilization organometallic complexes onto solid supports such as silica or alumina promising strategy catalyst heterogenization, often resulting increased activity stability. Consequently, broad early transition...
Attempts to synthesize the base-free dication [(C5Me5)2Th]2+ by reaction of bis(allyl) complex (C5Me5)2Th(C3H5)2 with 2 equiv [Et3NH][BPh4] in benzene yielded a cationic phenyl that, presence THF, crystallized from toluene as [(C5Me5)2Th(C6H5)(THF)][BPh4]. The dimethyl (C5Me5)2ThMe2 nitriles RCN generates cations formula [(C5Me5)2Th(NCR)5][BPh4]2 (R = Me, Ph) 40–55% crystalline yield. molecular structures reveal first examples thorium cyclopentadienyl metallocene complexes parallel rings.
Thin hafnium oxide films were prepared by atomic layer deposition using a carbon-free precursor, tetrakis(tetrahydroborato)hafnium [Hf(BH4)4], and H2O. Film growth was studied an in situ quartz crystal microbalance Fourier transform infrared spectroscopy measurements. Self-limiting observed between 100 175 °C, but the thermal decomposition of Hf precursor occurred at higher temperatures. The film properties investigated x-ray photoelectron spectroscopy, reflectivity, diffraction,...
Dimeric and monomeric supported single-site Fe(ii) pre-catalysts on SiO2 have been prepared via organometallic grafting characterized with advanced spectroscopic techniques. Manipulation of the surface hydroxyl concentration support influences monomer/dimer formation. While both are highly active in liquid-phase hydrogenation, dimeric pre-catalyst is ∼3× faster than monomer. Preliminary XAS experiments H2-activated samples suggest species isolated sites.
Tetrabutylammonium chloride and nitrate salts react with (C5Me5)2UCl2 to expand the coordination sphere of metallocene form formal 9- 10-coordinate complexes, [NBu4][(C5Me5)2UCl2(NO3)], 1, 2, respectively. Complex 2 displays modified reactivity compared that in substitution reactions Khpp [hpp =1,3,4,6,7,8-hexahydro-2H-pyrimido(1,2-a)pyrimidine] K(NC4Me4) synthesis (C5Me5)2U(hpp)Cl, (C5Me5)U(hpp)3, (C5Me5)2U(NC4Me4)Cl. The U3+ complex, [NBu4][(C5Me5)2UCl2], can be formed by reduction K(Hg),...
Understanding the mechanisms of action for base metal catalysis transformations typically associated with precious metals is essential design new technologies a sustainable energy economy. Isolated transition and post-transition catalysts on oxides such as silica are generally proposed to effect hydrogenation dehydrogenation by mechanism featuring either σ-bond metathesis or heterolytic bond cleavage key activation step. In this work an organovanadium(III) complex silica, which precatalyst...