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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Theoretical Examination Of Solvent And R Group Dependence In Gold Thiolate Nanoparticle Synthesis, Suzanne M. Neidhart, Brian M. Barngrover, Christine M. Aikens
Theoretical Examination Of Solvent And R Group Dependence In Gold Thiolate Nanoparticle Synthesis, Suzanne M. Neidhart, Brian M. Barngrover, Christine M. Aikens
Faculty Publications
The growth of gold thiolate nanoparticles can be affected by the solvent and the R group on the ligand. In this work, the difference between methanol and benzene solvents as well as the effect of alkyl (methyl) and aromatic (phenyl) thiols on the reaction energies and barrier heights is investigated theoretically. Density functional theory (DFT) calculations using the BP86 functional and a triple ζ polarized basis set show that the overall reaction favors methylthiol over phenylthiol with reaction energies of −0.54 and −0.39 eV in methanol, respectively. At the same level of theory, the methanol solvent is favored over the …
Prediction Of Nonradical Au (0)-Containing Precursors In Nanoparticle Growth Processes, Brian M. Barngrover, Timothy J. Manges, Christine M. Aikens
Prediction Of Nonradical Au (0)-Containing Precursors In Nanoparticle Growth Processes, Brian M. Barngrover, Timothy J. Manges, Christine M. Aikens
Faculty Publications
This density functional theory (DFT) investigation examines the formation of nonradical Au(0) species from the reduction of Au(I) species. The Au(I) complexes of interest are AuCl2–, AuBr2–, AuI2–, AuClPH3, and AuCl(H)SCH3(−), which are precursors for gold nanoparticle and cluster formation. Reaction of two of the Au(I) species with a hydride results in ejection of two of the ligands and formation of Au2 with two ligands still attached. AuX2– (where X = Cl, Br, or I) reactions eject two halides and form Au2 …
The Golden Pathway To Thiolate-Stabilized Nanoparticles: Following The Formation Of Gold (I) Thiolate From Gold (Iii) Chloride, Brian M. Barngrover, Christine M. Aikens
The Golden Pathway To Thiolate-Stabilized Nanoparticles: Following The Formation Of Gold (I) Thiolate From Gold (Iii) Chloride, Brian M. Barngrover, Christine M. Aikens
Faculty Publications
Pathways for the formation of gold thiolate complexes from gold(III) chloride precursors AuCl4– and AuCl3 are examined. This work demonstrates that two distinct reaction pathways are possible; which pathway is accessible in a given reaction may depend on factors such as the residue group R on the incoming thiol. Density functional theory calculations using the BP86 functional and a polarized triple-ζ basis set show that the pathway resulting in gold(III) reduction is favored for R = methyl. A two-to-one ratio of thiol or thiolate to gold can reduce Au(III) to Au(I), and a three-to-one ratio can lead …
Incremental Binding Energies Of Gold (I) And Silver (I) Thiolate Clusters, Brian M. Barngrover, Christine M. Aikens
Incremental Binding Energies Of Gold (I) And Silver (I) Thiolate Clusters, Brian M. Barngrover, Christine M. Aikens
Faculty Publications
Density functional theory is used to find incremental fragmentation energy, overall dissociation energy, and average monomer fragmentation energy of cyclic gold(I) thiolate clusters and anionic chain structures of gold(I) and silver(I) thiolate clusters as a measure of the relative stability of these systems. Two different functionals, BP86 and PBE, and two different basis sets, TZP and QZ4P, are employed. Anionic chains are examined with various residue groups including hydrogen, methyl, and phenyl. Hydrogen and methyl are shown to have approximately the same binding energy, which is higher than phenyl. Gold–thiolate clusters are bound more strongly than corresponding silver clusters. Lastly, …
Electron And Hydride Addition To Gold (I) Thiolate Oligomers: Implications For Gold–Thiolate Nanoparticle Growth Mechanisms, Brian M. Barngrover, Christine M. Aikens
Electron And Hydride Addition To Gold (I) Thiolate Oligomers: Implications For Gold–Thiolate Nanoparticle Growth Mechanisms, Brian M. Barngrover, Christine M. Aikens
Faculty Publications
Electron and hydride addition to Au(I):SR oligomers is investigated using density functional theory. Cyclic and chain-like clusters are examined in this work. Dissociation to Au– ions and Aun(SR)n+1– chains is observed after 2–4 electrons are added to these systems. The free thiolate (SR–) is rarely produced in this work; dissociation of Au– is preferred over dissociation of SR–. Electron affinities calculated in gas phase, toluene, and water suggest that the electron addition process is unlikely, although it may be possible in polar solvents. In contrast, hydride addition to Au(I):SR …
Structure–Mutagenicity Relationships And Energies Of 1-, And 2-Nitrotriphenylenes [Abstract], Kefa Karimu Onchoke
Structure–Mutagenicity Relationships And Energies Of 1-, And 2-Nitrotriphenylenes [Abstract], Kefa Karimu Onchoke
Faculty Publications
No abstract provided.
Structure And Vibrational Spectra Of Mononitrated Benzo [A] Pyrenes., Kefa Karimu Onchoke, Christopher M. Hadad, Prabir K. Dutta
Structure And Vibrational Spectra Of Mononitrated Benzo [A] Pyrenes., Kefa Karimu Onchoke, Christopher M. Hadad, Prabir K. Dutta
Faculty Publications
The molecules benzo[a]pyrene (BaP) and 1-, 3-, and 6-nitrobenzo[a]pyrene (1-NBaP, 3-NBaP, 6-NBaP) are currently of significant interest due to their presence in respirable combustion exhaust particulates and their mutagenic and carcinogenic properties. Structure−function correlations as well as spectroscopic signatures for trace analysis are necessary for these benzo[a]pyrene derivatives. In this paper, detailed infrared and Raman spectroscopic data of BaP and its three mononitrated isomers are provided for the first time. By utilizing density functional theory (DFT, B3LYP method with 6-311+G** basis set), the molecular geometries and the vibrational spectra are calculated. Good agreement is …