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Full-Text Articles in Physical Sciences and Mathematics

Electron Transfer By Excited Benzoquinone Anions: Slow Rates For Two-Electron Transitions, Matibur Zamadar, Andrew R. Cook, Anna Lewandowska-Andralojc, Richard Holroyd, Yan Jiang, Jin Bikalis, John R. Miller Jul 2013

Electron Transfer By Excited Benzoquinone Anions: Slow Rates For Two-Electron Transitions, Matibur Zamadar, Andrew R. Cook, Anna Lewandowska-Andralojc, Richard Holroyd, Yan Jiang, Jin Bikalis, John R. Miller

Faculty Publications

Electron transfer (ET) rate constants from the lowest excited state of the radical anion of benzoquinone, BQ−•*, were measured in THF solution. Rate constants for bimolecular electron transfer reactions typically reach the diffusion-controlled limit when the free-energy change, ΔG°, reaches −0.3 eV. The rate constants for ET from BQ−•* are one-to-two decades smaller at this energy and do not reach the diffusion-controlled limit until −ΔG° is 1.5−2.0 eV. The rates are so slow probably because a second electron must also undergo a transition to make use of the energy of the excited state. Similarly, ET, from solvated electrons to neutral …


Toward Designed Singlet Fission: Solution Photophysics Of Two Indirectly Coupled Covalent Dimers Of 1,3-Diphenylisobenzofuran, Justin C. Johnson, Akin Akdag, Matibur Zamadar, Xudong Chen, Andrew F. Schwerin, Irina Paci, Millicent B. Smith, Zdenek Havlas, John R. Miller, Mark A. Ratner, Arthur J. Nozik, Josef Michl Feb 2013

Toward Designed Singlet Fission: Solution Photophysics Of Two Indirectly Coupled Covalent Dimers Of 1,3-Diphenylisobenzofuran, Justin C. Johnson, Akin Akdag, Matibur Zamadar, Xudong Chen, Andrew F. Schwerin, Irina Paci, Millicent B. Smith, Zdenek Havlas, John R. Miller, Mark A. Ratner, Arthur J. Nozik, Josef Michl

Faculty Publications

In order to identify optimal conditions for singlet fission, we are examining the photophysics of 1,3- diphenylisobenzofuran (1) dimers covalently coupled in various ways. In the two dimers studied presently, the coupling is weak. The subunits are linked via the para position of one of the phenyl substituents, in one case (2) through a CH2 linker and in the other (3) directly, but with methyl substituents in ortho positions forcing a nearly perpendicular twist between the two joint phenyl rings. The measurements are accompanied with density functional theory (DFT) and timedependent DFT (TD-DFT) calculations. Although in neat solid state, 1 …


Ammonium Sulfate Precipitation Combined With Liquid Chromatography Is Sufficient For Purification Of Bovine Serum Albumin That Is Suitable For Most Routine Laboratory Applications, Odutayo O. Odunuge, Alina Shazhko Jan 2013

Ammonium Sulfate Precipitation Combined With Liquid Chromatography Is Sufficient For Purification Of Bovine Serum Albumin That Is Suitable For Most Routine Laboratory Applications, Odutayo O. Odunuge, Alina Shazhko

Faculty Publications

The use of bovine serum albumin (BSA) in routine biochemical assays such as restriction enzyme digestion and immunodetection is plagued largely by two common contaminants, DNase and immunoglobulins G (IgGs). Acetylation of BSA to inactivate DNase limits its use as a protein standard due to interference with color development in assays such as Lowry’s. In spite of the availability of inexpensive BSA, its purification involves several cumbersome and time-consuming steps. In this work, we employed a modified strategy of ammonium sulfate precipitation coupled with liquid chromatography to purify BSA that is free of DNase and IgGs. Purified BSA tested negative …


A Dft Study Of Vibrational Spectra And Mutagenicity Predictions Of Mononitrated Fluoranthenes [Abstract], Kefa Karimu Onchoke, Jorge Ojeda Jan 2013

A Dft Study Of Vibrational Spectra And Mutagenicity Predictions Of Mononitrated Fluoranthenes [Abstract], Kefa Karimu Onchoke, Jorge Ojeda

Faculty Publications

No abstract provided.


Oxidation Of Gold Clusters By Thiols, Brian M. Barngrover, Christine M. Aikens Jan 2013

Oxidation Of Gold Clusters By Thiols, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

The formation of gold–thiolate nanoparticles via oxidation of gold clusters by thiols is examined in this work. Using the BP86 density functional with a triple ζ basis set, the adsorption of methylthiol onto various gold clusters AunZ (n = 1–8, 12, 13, 20; Z = 0, −1, +1) and Au384+ is investigated. The rate-limiting step for the reaction of one thiol with the gold cluster is the dissociation of the thiol proton; the resulting hydrogen atom can move around the gold cluster relatively freely. The addition of a second thiol can lead to H2 …