A5022090989- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Synthesis and Properties of Aromatic Compounds
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- Organometallic Complex Synthesis and Catalysis
- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Supramolecular Chemistry and Complexes
- Crystallography and molecular interactions
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Catalytic C–H Functionalization Methods
- Luminescence and Fluorescent Materials
- Luminescence Properties of Advanced Materials
- Carbon dioxide utilization in catalysis
- Catalytic Cross-Coupling Reactions
- Advanced battery technologies research
- Cyclopropane Reaction Mechanisms
- Electrocatalysts for Energy Conversion
- Radical Photochemical Reactions
- International Science and Diplomacy
- Fullerene Chemistry and Applications
- Catalysis and Hydrodesulfurization Studies
- Zeolite Catalysis and Synthesis
- Catalytic Alkyne Reactions
Sandia National Laboratories California
2023-2024
Argonne National Laboratory
2020-2023
University of California, Berkeley
2018-2022
Lawrence Berkeley National Laboratory
2020-2022
Berkeley College
2019
The field of Surface Organometallic Chemistry (SOMC) aims to blend the positive attributes homogeneous and heterogeneous catalysis. Significant insight into systems has been gained over years through synthesis, characterization, application well-defined surface organometallic catalysts, predominantly supported on silica alumina. Considerable research efforts have focused methods synthesis characterization these systems. Homogeneous catalysis thrived its ability electronically sterically tune...
A general synthetic strategy for the construction of large, nitrogen-containing polycyclic aromatic hydrocarbons (PAHs) is reported. The involves two key steps: (1) a titanocene-mediated reductive cyclization an oligo(dinitrile) precursor to form PAH appended with di(aza)titanacyclopentadiene functionality; (2) divergent titanocene transfer reaction, which allows final-step installation one or more o-quinone, diazole, pyrazine units into framework. new methodology enables rational,...
Pentacene's extraordinary photophysical and electronic properties are highly dependent on intermolecular through-space interactions. Macrocyclic arrangements of chromophores have been shown to provide a high level control over these interactions, but few examples exist for pentacene due inherent synthetic challenges. In this work, zirconocene-mediated alkyne coupling was used as dynamic covalent C–C bond forming reaction synthesize two geometrically distinct, pentacene-containing macrocycles...
The synthesis and reactivity of the first open-shell two-coordinate silyl complex, (IPr)Ni-Si(SiMe3)3, (IPr = 1,3-di(2,6-di-iso-propylphenyl)imidazolin-2-ylidene) is reported. Reaction with CO2 results in a novel insertion product that possesses distorted geometry. Oxidations Ni center, [Cp2Fe][B(C6F5)4] Ph3CCl, result migratory rearrangements ligand, apparently via related silylene intermediates. distinct oxidation products are interconverted by reactions introduce or remove chloride.
A series of supported electrophilic organoruthenium complexes has been synthesized via surface organometallic chemistry (SOMC) techniques and applied to the selective hydrosilylation olefins. The air-sensitive 16e– complex Cp*RuMes(PCy3) (1) (Cp* = pentamethylcyclopentadienyl, Mes mesityl) was by treatment Cp*RuCl(PCy3) with mesityl Grignard MesMgBr. This species chemisorbed onto sulfated zirconia SO4/ZrO2, but resulting material inactive toward cyclohexene phenylsilane. Instead, treated...
The two-coordinate compound (IPr)Fe[N(SiMe3)DIPP] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; DIPP 2,6-diisopropylphenyl) catalyzes the cyclotrimerization of alkynes to arenes. Treatment Fe complex with 1 equiv diphenylacetylene results in formation a bimetallic bridging alkyne complex, along dissociation IPr from Fe. At elevated temperatures, undergoes oxidative coupling form dimetallacyclopentadiene formally by one-electron oxidation at each metal center. Each...
The development of general strategies for the electronic tuning a catalyst's active site is an ongoing challenge in heterogeneous catalysis. To this end, herein, we describe application Li-ion battery cathode and anode materials as redox non-innocent catalyst supports that can be continuously modulated function lithium intercalation. A zero-valent nickel complex was oxidatively grafted onto surface manganese oxide (LixMn2O4) to yield isolated Ni2+ occupying vacant interstitial octahedral Li...
The synthesis and reactivity of a dimeric Ni(I) methyl complex, [(IPr)Ni(μ-CH3)]2, (1; IPr = 1,3-bis(2,6-di-isopropylphenyl)imidazolin-2-ylidene) is reported. Reaction with CO2 results in the formation bridging Ni(II) carbonate species. Additionally, 1 activates variety element-H bonds to form methane new Ni-element linkages. In one instance, treatment SiH4 resulted Si–H bond activation silylene [(IPr)NiH(μ-SiH2)]2. Finally, complex competent catalyst for coupling CH3MgCl aryl halides.
Organometallic catalysts with strong metal-to-ligand charge-transfer (MLCT) optical transitions and reactive metal–hydride bonds provide opportunities for new excited-state reactivity. Toward this end, we have investigated photoinduced transfer hydrogenation reactions a series of Cp*IrH complexes functionalized bipyridyl ligands. Overcoming the baseline reactivity class catalyst toward hydrogen evolution in aqueous media presents major challenge focusing photochemical into desired...
Sequential treatment of Fe[N(SiMe3)DIPP]2 (2) with Et3NHCl, IAd, and KC8 (IAd = 1,3-diadamantyl-imidazolin-2-ylidene, DIPP 2,6-diisopropylphenyl) results in the formation two new complexes, (IAd)Fe[N(SiMe3)DIPP]2 (3) {(IAd)Fe[N(SiMe3)DIPP]}2(μ-N2) (4), via disproportionation N2 trapping intermediate species (IAd)Fe[N(SiMe3)DIPP] (A), respectively. Independent syntheses complexes 3 4 were also developed. These differ from those observed IPr-supported analogue (IPr...
The low-coordinate monovalent cobalt complex (IPr)Co[N(SiMe3)DIPP] [2, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; DIPP 2,6-diisopropylphenyl], supported by bulky amide and N-heterocyclic carbene (NHC) ligands its 9-diazofluorene (FluN2) adduct (IPr)Co[N(SiMe3)DIPP](FluN2) (3) are described. Complex 3 was characterized as possessing a high-spin divalent center antiferromagnetically coupled to ligand-based radical, resulting in an overall triplet spin ground state (S 1). Both 2...
Low-coordinate titanium(III) amido complexes were readily prepared via treatment of β-TiCl3 with 1 or 2 equiv Li[N(SiiPr3)DIPP] (DIPP = 2,6-di-iso-propylphenyl) to form dinuclear [{Ti(N(SiiPr3)DIPP)Cl(μ-Cl)}2] (1) mononuclear Ti[N(SiiPr3)DIPP]2Cl (2), respectively. Both characterized by a variety methods, including NMR spectroscopy, Evans method magnetic susceptibility, and single-crystal X-ray diffraction studies. Complex was shown be versatile precursor for salt metathesis reactions...
Plastic scintillators are widely used as radiation detection media in homeland security and nuclear physics applications. Their attributes include low cost, scalability to large detector volumes, additive compounding enable additional material features, such pulse shape discrimination (PSD), gamma-ray spectroscopy, aging resistance, coincidence timing. However, traditional chemically cured plastic (CCS) require long reaction times, hazardous wet chemical procedures performed by specially...
Abstract Anionic molecular models for nonhydrolyzed and partially hydrolyzed aluminum gallium framework sites on silica, M[OSi(O t Bu) 3 ] 4 − HOM[OSi(O (where M=Al or Ga), were synthesized from anionic chlorides Li{M[OSi(O Cl} in salt metathesis reactions. Sequestration of lithium cations with [12]crown‐4 afforded charge‐separated ion pairs composed monomeric anions outer‐sphere [([12]crown‐4) 2 Li] + cations, hydroxides {HOM[OSi(O } pendant [([12]crown‐4)Li] cations. These characterized by...
Pentacene’s extraordinary photophysical and electronic properties are highly dependent on intermolecular, through-space interactions. Macrocyclic arrangements of chromophores have been shown to provide a high level control over these interactions, but few examples exist for pentacene due inherent synthetic challenges. In this work, zirconocene-mediated alkyne coupling was used as dynamic covalent C-C bond forming reaction synthesize two geometrically distinct, pentacene-containing...
Multi-mode radiation detectors capable of gamma-ray spectroscopy are needed as the next generation portal monitors (RPMs) at ports entry along nation's borders. Inorganic scintillators difficult to procure in large volumes for monitoring and their cost can be prohibitive. Plastic that currently used RPMs produced very low cost, but due density effective atomic number (Zeff), limited gross counting. To meet performance size requirements RPMs, RMD SNL developing metal-loaded Polymer Organic...