A5053893566- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Crystallography and molecular interactions
- Radioactive element chemistry and processing
- Organometallic Complex Synthesis and Catalysis
- Lanthanide and Transition Metal Complexes
- Coordination Chemistry and Organometallics
- Nuclear Materials and Properties
- Magnetism in coordination complexes
- Nanocluster Synthesis and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Inorganic Chemistry and Materials
- Synthesis and characterization of novel inorganic/organometallic compounds
- Metal complexes synthesis and properties
- Chemical Synthesis and Characterization
- Radiopharmaceutical Chemistry and Applications
- Radioactive contamination and transfer
- Gold and Silver Nanoparticles Synthesis and Applications
- Polyoxometalates: Synthesis and Applications
- Catalysis and Oxidation Reactions
- Oxidative Organic Chemistry Reactions
- Advanced Nanomaterials in Catalysis
- Metalloenzymes and iron-sulfur proteins
- Carbon dioxide utilization in catalysis
- Vanadium and Halogenation Chemistry
University of California, Santa Barbara
2016-2025
Santa Barbara City College
2015-2020
University of California System
2015-2020
Robert Bosch (Germany)
2020
University at Buffalo, State University of New York
2019
Technische Universität Berlin
2013
North Carolina State University
2013
Los Alamos National Laboratory
2005-2008
University of British Columbia
2002-2005
University of Florida
2005
In the last few years, considerable progress has been made in synthesis and characterization of complexes containing actinide–ligand multiple bonds, especially regards to isolation terminal oxo, nitrido carbene-containing complexes. This review summarizes synthesis, structure, reactivity these complexes, from 2010 until present. These are interest for a variety reasons, including their potential use novel catalytic transformations ability engage 5f orbitals metal–ligand bonding. Of...
Atomically precise copper nanoclusters (NCs) are of immense interest for a variety applications, but have remained elusive. Herein, we report the isolation NC, [Cu25H22(PPh3)12]Cl (1), from reaction Cu(OAc) and CuCl with Ph2SiH2, in presence PPh3. Complex 1 has been fully characterized, including analysis by X-ray crystallography, XANES, XPS. In solid state, complex is constructed around Cu13 centered-icosahedron formally features partial Cu(0) character. XANES reveals Cu K-edge at 8979.6...
There is a growing interest in uranium coordination chemistry, particularly as it relates to metal-ligand multiple bonding, and the last decade significant progress has been made synthesizing oxo, imido, mu-nitrido, carbene-containing complexes of uranium. This review summarizes synthesis, structure reactivity these complexes, starting from inception field 1981. Particular attention focused on recent developments this area, such synthesis bis(imido) analogues uranyl ion, isolation first...
Here we describe the synthesis of two imido analogs uranyl ion, UO(2+)2, in which oxygens are replaced by divalent alkyl or aryl nitrogen groups: U(NtBu)2I2(THF)2 (1) and U(NPh)2I2(THF)3 (2) (where tBu is tert-butyl THF tetrahydrofuran). Both compounds have been fully characterized standard analytical techniques, including x-ray crystallography, chemical bonding between metal center ligands was quantified using hybrid density functional theory calculations. As expected for a analog, these...
The development of atomically precise nanoclusters (APNCs) protected by organometallic ligands, such as acetylides and hydrides, is an emerging area nanoscience. In principle, these APNCs should not require harsh pretreatment for activation toward catalysis, calcination, which can lead to sintering. Herein, we report the synthesis mixed-valent copper APNC, [Cu20(CCPh)12(OAc)6)] (1), via reduction Cu(OAc) with Ph2SiH2 in presence phenylacetylene. This cluster a rare example two-electron...
Addition of 0.5 equiv NaN3 to U[NR2]3 (R = SiMe3) affords the metallacycle [Na(DME)2(TMEDA)][(NR2)2U(μ-N)(CH2SiMe2NR)U(NR2)2] (1) in 69% yield. Complex 1 is readily oxidized by I2, generating mixed valent U(IV/V) nitrido complex (NR2)2U(μ-N)(CH2SiMe2NR)U(NR2)2 (2). Alternatively, oxidation with Me3NO oxo-nitrido [Na(DME)2][(NR2)2(O)U(μ-N)(CH2SiMe2NR)U(NR2)2] (3) good The solid-state molecular structures 1−3 have been determined X-ray crystallography. A notable feature these complexes are...
Reaction of [Th(I)(NR2)3] (R = SiMe3) (1) with 1 equiv either [K(18-crown-6)]2[Se4] or [K(18-crown-6)]2[Te2] affords the thorium dichalcogenides, [K(18-crown-6)][Th(η(2)-E2)(NR2)3] (E Se, 2; E Te, 3), respectively. Removal one chalcogen atom via reaction Et3P, Et3P and Hg, monoselenide monotelluride complexes thorium, [K(18-crown-6)][Th(E)(NR2)3] 4; 5), Both 4 5 were characterized by X-ray crystallography found to feature shortest known Th-Se Th-Te bond distances. The electronic structure...
The copper hydride nanocluster (NC) [Cu29Cl4H22(Ph2phen)12]Cl (2; Ph2phen = 4,7-diphenyl-1,10-phenanthroline) was isolated cleanly, and in good yields, by controlled growth from the smaller NC, [Cu25H22(PPh3)12]Cl (1), presence of a chloride source at room temperature. Complex 2 fully characterized single-crystal X-ray diffraction, XANES, XPS, represents rare example an N* superatom. Its formation 1 demonstrates that atomically precise clusters can be used as templates to generate larger NCs...
ConspectusAtomically precise nanoclusters (APNCs) are an emerging area of nanoscience. Their monodispersity and well-defined arrangement capping ligands facilitates the interrogation their fundamental physical properties, allowing for development structure–function relationships, as well optimization a variety applications, including quantum computing, solid-state memory, catalysis, sensing, imaging. However, APNCs present several unique synthetic characterization challenges. For example,...
Addition of 1 equiv 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) to U(NR(2))(3) in hexanes affords U(O)(NR(2))(3) (2), which can be isolated 73% yield. Complex 2 is a rare example terminal U(V) oxo complex. In contrast, addition Me(3)NO (R = SiMe(3)) pentane generates the U(IV) bridging [(NR(2))(3)U](2)(μ-O) (3) moderate yields. Also formed this reaction, low yield, iodide complex U(I)(NR(2))(3) (4). The ligand 4 likely originates from residual NaI, present starting material. generated...
Addition of 1 equiv E (E = 0.125 S(8), Se, Te) to U(H(2)C═PPh(3))(NR(2))(3) (R SiMe(3)) (1) in Et(2)O results generation the terminal chalcogenide complexes, [Ph(3)PCH(3)][U(E)(NR(2))(3)] S, 2; 3; Te, 4; R SiMe(3)), modest yield. Complexes 2-4 represent extremely rare examples uranium monochalcogenides. Synthesis oxo analogue, [Cp*(2)Co][U(O)(NR(2))(3)] (5), was achieved by reduction [U(O)(NR(2))(3)] with Cp*(2)Co. All complexes were fully characterized, including analysis X-ray...
Addition of 1.5 equiv I2 to a THF solution UI3(THF)4, containing either 6 tBuNH2 or 2 RNH2 (R = Ph, 3,5-(CF3)2C6H3, 2,6-(iPr)2C6H3) and 4 NEt3, generates orange solutions U(NtBu)2I2(THF)2 (1) U(NAr)2I2(THF)3 (Ar 2; 3; 2,6-(iPr)2C6H3, 4), respectively, all which can be isolated in good yields. Alternatively, 1 prepared by reaction uranium metal with 3 tBuNH2, also yield. Complexes 1-4 have been characterized X-ray crystallography, each these complexes exhibits linear N-U-N linkages short U-N...
Addition of the Wittig reagent Ph(3)P═CH(2) to U(III) tris(amide) U(NR(2))(3) (R = SiMe(3)) generates a mixture products from which U(IV) complex U═CHPPh(3)(NR(2))(3) (2) can be obtained. Complex 2 features short U═C bond and represents rare example uranium carbene. In solution, exists in equilibrium with metallacycle U(CH(2)SiMe(2)NR)(NR(2))(2) free Ph(3)P═CH(2). Measurement this as function temperature provides ΔH(rxn) 11 kcal/mol ΔS(rxn) 31 eu. Additionally, electronic structure was...
Treatment of the U(III)-ylide adduct U(CH(2)PPh(3))(NR(2))(3) (1, R = SiMe(3)) with TEMPO generates U(V) oxo metallacycle [Ph(3)PCH(3)][U(O)(CH(2)SiMe(2)NSiMe(3))(NR(2))(2)] (2) via O-atom transfer, in good yield. Oxidation 2 0.85 equiv AgOTf affords neutral U(VI) species U(O)(CH(2)SiMe(2)NSiMe(3))(NR(2))(2) (3). The electronic structures and 3 are investigated by DFT analysis. Additionally, nucleophilicity ligands toward Me(3)SiI is explored.
Addition of 1 equiv Li(Ar2nacnac) (Ar2nacnac = (2,6-(i)Pr2C6H3)NC(Me)CHC(Me)N(2,6-(i)Pr2C6H3)) to an Et2O suspension UO2Cl2(THF)3 generates the uranyl dimer [UO2(Ar2nacnac)Cl]2 (1) in good yield. A second species can be isolated low yield from reaction mixtures 1, namely [Li(OEt2)2][UO2(Ar2nacnac)Cl2] (2). The structures both and 2 have been confirmed by X-ray crystallography. Complex reacts with Ph3PO generate UO2(Ar2nacnac)Cl(Ph3PO) (3). In addition, AgOTf either DPPMO2 or Ph2MePO provide...
f Orbital bonding in actinide and lanthanide complexes is critical to their behavior a variety of areas from separations magnetic properties. Octahedral f(1) hexahalide have been extensively used study orbital due simple electronic structure extensive spectroscopic characterization. The recent expansion this family include alkyl, alkoxide, amide, ketimide ligands presents the opportunity extend wider ligands. To better understand these complexes, existing molecular (MO) model was refined...
The addition of 4.5 equiv LiCH(2)SiMe(3) to [Li(THF)](2)[U(O(t)Bu)(6)], in the presence LiCl, results formation homoleptic uranium(IV) alkyl complex [Li(14)(O(t)Bu)(12)Cl][U(CH(2)SiMe(3))(5)] (1) low yield. Complex 1 has been characterized by X-ray crystallography. As a solid, is thermally stable for several days at room temperature. However, rapidly decomposes C(6)D(6), as indicated (1)H and (7)Li{(1)H} NMR spectroscopy, owing lability [Li(14)(O(t)Bu)(12)Cl](+) cation. To avoid counterion,...
Synthetic routes to salts containing uranium bis-imido tetrahalide anions [U(NR)(2)X(4)](2-) (X = Cl(-), Br(-)) and non-coordinating NEt(4)(+) PPh(4)(+) countercations are reported. In general, these compounds can be prepared from U(NR)(2)I(2)(THF)(x) (x 2 R (t)Bu, Ph; x 3 Me) upon addition of excess halide. providing stable coordination complexes with the [U(NMe)(2)](2+) cation also reacts Br(-) form [NEt(4)](2)[U(NMe)(2)Br(4)] complexes. These materials were used as a platform compare...
Addition of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) to MCl(3) (M = Fe, Al) results in the formation MCl(3)(η(1)-TEMPO) [M Fe (1), Al (2)]. Both 1 and 2 oxidize alcohols generate ketones or aldehydes along with reduced complexes MCl(3)(η(1)-TEMPOH) (3), (4)]. Complexes 1-4 were fully characterized, including analysis by X-ray crystallography. Additionally, control experiments indicated that neither Al, Fe) nor TEMPO are capable effecting oxidation independently.
Oxidation of [Li(DME)(3)][U(CH(2)SiMe(3))(5)] with 0.5 equiv I(2), followed by immediate addition LiCH(2)SiMe(3), affords the high-valent homoleptic U(V) alkyl complex [Li(THF)(4)][U(CH(2)SiMe(3))(6)] (1) in 82% yield. In solid-state, 1 adopts an octahedral geometry as shown X-ray crystallographic analysis. Addition 2 tert-butanol to generates heteroleptic U(IV) [Li(DME)(3)][U(O(t)Bu)(2)(CH(2)SiMe(3))(3)] (2) high Treatment AgOTf fails produce a derivative, but instead...
A series of tetravalent An(IV) complexes with a bis-phenyl β-ketoiminate N,O donor ligand has been synthesized the aim identifying bonding trends and changes across actinide series. The neutral molecules are homoleptic formula An((Ar)acnac)(4) (An = Th (1), U (2), Np (3), Pu (4); (Ar)acnac ArNC(Ph)CHC(Ph)O; Ar 3,5-(t)Bu(2)C(6)H(3)) were through salt metathesis reactions chloride precursors. NMR electronic absorption spectroscopy confirm purity all four new compounds demonstrate stability in...
Addition of E (E = 0.125S8, Se) to [Cp*2Co][U(O)(NR2)3] (R SiMe3) in THF results the isolation chalcogen-substituted uranyl analogues [Cp*2Co][U(O)(E)(NR2)3] [E S (1), Se (2)] good yields. Similarly, addition 1 equiv 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) affords complex [Cp*2Co][UO2(NR2)3] (3). All complexes were fully characterized, including analysis by X-ray crystallography. They also analyzed density functional theory calculations probe changes U-E bond as group 16 is descended.