60 results on '"Susan A. Odom"'
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2. Comparison of Separators vs Membranes in Nonaqueous Redox Flow Battery Electrolytes Containing Small Molecule Active Materials
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Susan A. Odom, N. Harsha Attanayake, William L. Eubanks, James Landon, Aman Preet Kaur, Fikile R. Brushett, Bertrand J. Neyhouse, Katharine V. Greco, Zhiming Liang, and John L. Barton
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Chemistry ,Energy Engineering and Power Technology ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Flow battery ,Redox ,Small molecule ,0104 chemical sciences ,Membrane ,Chemical engineering ,Materials Chemistry ,Electrochemistry ,Chemical Engineering (miscellaneous) ,Electrical and Electronic Engineering ,0210 nano-technology - Published
- 2021
3. Ethynylated Acene Synthesis and Photophysics for an Organic Chemistry Laboratory Course
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Anthony J. Petty and Susan A. Odom
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chemistry.chemical_classification ,010405 organic chemistry ,Silica gel ,05 social sciences ,Diol ,050301 education ,Alkyne ,General Chemistry ,01 natural sciences ,Fluorescence spectroscopy ,0104 chemical sciences ,Education ,Quinone ,chemistry.chemical_compound ,Ultraviolet visible spectroscopy ,chemistry ,Molecule ,Organic chemistry ,0503 education ,Acene - Abstract
An operationally simple, reliable synthesis of ethynylated acenes suitable for an upper-division undergraduate organic chemistry laboratory course has been developed. This experiment requires students to synthesize two acene derivatives and can be completed in 6–8 laboratory sessions (3 h each); a shorter experiment could be realized in the synthesis of only one product. Synthesis is carried out by first treating a terminal alkyne with n-butyllithium in an oven-dried flask under nitrogen at 0 °C. An acene quinone is added, which produces a doubly ethynylated diol. Dehydration with SnCl2/HCl yields a bis(ethynylated) acene, which is purified via a short pad or column of silica gel. The intense colors of the products allow for great ease in determining reaction completion and following the products in chromatography. UV–vis and fluorescence spectroscopy may be used to better understand the effect of molecular structure on electronic properties.
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- 2021
4. Quantifying Environmental Effects on the Solution and Solid-State Stability of a Phenothiazine Radical Cation
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Susan A. Odom, Oliver C. Harris, Zhiming Liang, Maureen H. Tang, Aman Preet Kaur, N. Harsha Attanayake, and Sean Parkin
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Chemical process ,General Chemical Engineering ,Solid-state ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Radical ion ,Computational chemistry ,Phenothiazine ,Materials Chemistry ,0210 nano-technology - Abstract
Organic radical cations are important intermediates in a wide variety of chemical processes. To date, significant progress has been made to improve the stability of these charged materials for use ...
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- 2020
5. Improved synthesis of N-ethyl-3,7-bis(trifluoromethyl)phenothiazine
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N. Harsha Attanayake, Selin Ergun, Aman Preet Kaur, Susan A. Odom, Matthew D. Casselman, and Sean Parkin
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chemistry.chemical_classification ,Overcharge ,Trifluoromethyl ,Salt (chemistry) ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,Medicinal chemistry ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Radical ion ,chemistry ,Phenothiazine ,Materials Chemistry ,Carbonate ,Graphite ,0210 nano-technology - Abstract
N-Ethyl-3,7-bis(trifluoromethyl)phenothiazine is a highly soluble redox shuttle for overcharge protection in lithium-ion batteries with an oxidation potential of ca. 3.8 V vs. Li+/0 in carbonate solvents. This compound has enabled extensive overcharge protection of LiFePO4/graphite cells and does so at high charging rates at high concentrations. Our initial synthesis of this compound suffered from low yields and difficult purifications. Here we report a cleaner, higher-yielding synthesis and additional characterization of the product and its stable radical cation salt.
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- 2020
6. Mitigating Chemical Paths to Capacity Fade in Organic Flow Batteries
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Susan A. Odom
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genetic structures ,Chemistry ,General Chemical Engineering ,Biochemistry (medical) ,Flow (psychology) ,02 engineering and technology ,General Chemistry ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,behavioral disciplines and activities ,01 natural sciences ,Biochemistry ,Flow battery ,Redox ,Chemical reaction ,eye diseases ,0104 chemical sciences ,chemistry.chemical_compound ,Chemical engineering ,Anthraquinones ,Materials Chemistry ,Environmental Chemistry ,Fade ,0210 nano-technology - Abstract
In this issue of Chem, Michael Aziz, Roy Gordon, and collaborators report soluble, functionalized anthraquinones that serve to deactivate and recover from chemical reactions that lead to capacity fade in organic redox flow battery electrolytes. The result is an unprecedented low rate of capacity fade of
- Published
- 2020
7. Tailoring Two-Electron-Donating Phenothiazines To Enable High-Concentration Redox Electrolytes for Use in Nonaqueous Redox Flow Batteries
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Steven J. Chapman, Jeffrey A. Kowalski, N. Harsha Attanayake, Susan A. Odom, Matthew D. Casselman, Sean Parkin, Fikile R. Brushett, Jarrod D. Milshtein, and Katharine V. Greco
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High concentration ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,02 engineering and technology ,General Chemistry ,Electrolyte ,Electron ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Redox ,0104 chemical sciences ,Materials Chemistry ,0210 nano-technology - Abstract
This study aims to advance our understanding of the physical and electrochemical behavior of nonaqueous redox electrolytes at elevated concentrations and to develop experimentally informed structur...
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- 2019
8. Extending the Lifetime of Organic Flow Batteries via Redox State Management
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Daniel A. Pollack, Michael J. Aziz, Roy G. Gordon, Marc-Antoni Goulet, Liuchuan Tong, Eugene E. Kwan, Susan A. Odom, Alán Aspuru-Guzik, and Daniel P. Tabor
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business.industry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Decomposition ,Anthrone ,Redox ,Anthraquinone ,Catalysis ,Energy storage ,0104 chemical sciences ,Quinone ,Renewable energy ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Chemical engineering ,Capacity loss ,business - Abstract
Redox flow batteries based on quinone-bearing aqueous electrolytes have emerged as promising systems for energy storage from intermittent renewable sources. The lifetime of these batteries is limited by quinone stability. Here, we confirm that 2,6-dihydroxyanthrahydroquinone tends to form an anthrone intermediate that is vulnerable to subsequent irreversible dimerization. We demonstrate quantitatively that this decomposition pathway is responsible for the loss of battery capacity. Computational studies indicate that the driving force for anthrone formation is greater for anthraquinones with lower reduction potentials. We show that the decomposition can be substantially mitigated. We demonstrate that conditions minimizing anthrone formation and avoiding anthrone dimerization slow the capacity loss rate by over an order of magnitude. We anticipate that this mitigation strategy readily extends to other anthraquinone-based flow batteries and is thus an important step toward realizing renewable electricity storage through long-lived organic flow batteries.
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- 2019
9. Correction to 'Extending the Lifetime of Organic Flow Batteries via Redox State Management'
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Marc-Antoni Goulet, Liuchuan Tong, Eugene E. Kwan, Daniel A. Pollack, Daniel P. Tabor, Michael J. Aziz, Roy G. Gordon, Alán Aspuru-Guzik, and Susan A. Odom
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Colloid and Surface Chemistry ,Flow (mathematics) ,business.industry ,Chemistry ,General Chemistry ,Process engineering ,business ,Biochemistry ,Redox ,Catalysis - Published
- 2021
10. Steric Manipulation as a Mechanism for Tuning the Reduction and Oxidation Potentials of Phenothiazines
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Kate E. Fraser, Corrine F. Elliott, Chad Risko, and Susan A. Odom
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Steric effects ,chemistry.chemical_compound ,Molecular geometry ,Computational chemistry ,Chemistry ,Ionization ,Phenothiazine ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,Ionization energy ,Redox - Abstract
Synthetic chemists customarily tune the redox characteristics of π-conjugated molecules by introducing electron-donating or electron-withdrawing substituents onto the molecular core, or by modifying the length of the π-conjugated pathway. Any steric effects of such efforts on molecular geometry typically affect both the neutral and charged (oxidized or reduced) states indiscriminately. However, in electroactive systems that undergo significant conformational changes upon oxidation or reduction, we can leverage the steric and inductive effects of substitution to attain considerable control over individual redox potentials. Here, we make use of density functional theory to elucidate the interplay between electronic and geometric effects of peripheral substitution on the model system of phenothiazine. For instance, we introduce substituents at positions ortho to the nitrogen atom (positions 1 and 9) to induce steric strain in the radical-cation state without significant effect on the neutral molecule, thereby augmenting the overall ionization potential. Notably, this steric effect persists for electron-donating substituents; the resulting ionization potentials therefore deviate from outcomes foretold by Hammett constants. Moreover, the same procedure has limited effect on electron affinities because of differences in phenothiazines' relaxation process upon reduction compared to oxidation. Our results promote molecular design guidelines for manipulating redox potentials in classes of electroactive compounds that experience dramatic changes in geometry upon ionization.
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- 2021
11. Viscous flow properties and hydrodynamic diameter of phenothiazine-based redox-active molecules in different supporting salt environments
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Lei Cheng, N. Harsha Attanayake, Aman Preet Kaur, Zhou Yu, Thilini M. Suduwella, Susan A. Odom, Randy H. Ewoldt, and Yilin Wang
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Fluid Flow and Transfer Processes ,Physics ,Mechanical Engineering ,Intrinsic viscosity ,Diffusion ,Computational Mechanics ,FOS: Physical sciences ,Viscometer ,Thermodynamics ,Condensed Matter - Soft Condensed Matter ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Shear rate ,Solvent ,Viscosity ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,0103 physical sciences ,Soft Condensed Matter (cond-mat.soft) ,Density functional theory ,010306 general physics ,Acetonitrile - Abstract
We report viscous flow properties of a redox-active organic molecule, N-(2-(2-methoxyethoxy)ethyl)phenothiazine (MEEPT), a candidate for non-aqueous redox flow batteries, and two of its radical cation salts. A microfluidic viscometer enabled the use of small sample volumes in determining viscosity as a function of shear rate and concentration in the non-aqueous solvent, acetonitrile, both with and without supporting salts. All solutions tested show Newtonian behavior over shear rates of up to 30,000 1/s, which is rationalized by scaling arguments for the diffusion-based relaxation time of a single MEEPT molecule without aggregation. Neat MEEPT is flowable but with a large viscosity (412 mPa s) at room temperature), which is approximately 1,000 times larger than acetonitrile. When dissolved in acetonitrile, MEEPT solutions have low viscosities; at concentrations up to 0.5 M, the viscosity increases by less than a factor of two. From concentration-dependent viscosity measurements, molecular information is inferred from intrinsic viscosity (hydrodynamic diameter) and the Huggins coefficient (interactions). Model fit credibility is assessed using the Bayesian Information Criterion (BIC). It is found that the MEEPT and its charged cation are "flowable" and do not flocculate at concentrations up to 0.5 M. MEEPT has a hydrodynamic diameter of around 0.85 nm, which is largely insensitive to supporting salt and state of charge. This size is comparable to molecular dimensions of single molecules obtained from optimized structures using density function theory calculations. The results suggest that MEEPT is a promising candidate for redox flow batteries in terms of its viscous flow properties., 22 pages, 11 figures in manuscript; 8 pages, 5 figures in supporting information
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- 2020
12. Application of Cross-Linked Polyborosiloxanes and Organically Modified Boron Silicate Binders in Silicon-Containing Anodes for Lithium-Ion Batteries
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Yang-Tse Cheng, Darius A. Shariaty, Dali Qian, and Susan A. Odom
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Materials science ,Silicon ,Renewable Energy, Sustainability and the Environment ,020209 energy ,chemistry.chemical_element ,02 engineering and technology ,Condensed Matter Physics ,Silicate ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Anode ,Ion ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Materials Chemistry ,Electrochemistry ,Lithium ,Boron - Published
- 2018
13. Determining Parasitic Reaction Enthalpies in Lithium-Ion Cells Using Isothermal Microcalorimetry
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Aman Preet Kaur, Stephen Glazier, Susan A. Odom, and J. R. Dahn
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Isothermal microcalorimetry ,Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,chemistry ,Parasitic reaction ,0202 electrical engineering, electronic engineering, information engineering ,Materials Chemistry ,Electrochemistry ,Lithium - Published
- 2018
14. Combined Computational and Experimental Approach to Determine and Understand the Solubility of Phenothiazines as Redoxmers
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Rahul Kant Jha, Matthew S. Sigman, Aman Preet Kaur, Alexandria Watrous, Chad Risko, Thillini Malsha Suduwella, Anton Sameera Perera, Sophia G. Robinson, and Susan A. Odom
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Computational chemistry ,Chemistry ,Solubility - Published
- 2021
15. Crowded electrolytes containing redoxmers in different states of charge: Solution structure, properties, and fundamental limits on energy density
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Rajeev S. Assary, Zhou Yu, Hossam Farag, Lei Cheng, Tao Li, T. Malsha Suduwella, Aman Preet Kaur, Randy H. Ewoldt, Xinyi Liu, Erik Sarnello, Lily A. Robertson, Susan A. Odom, Yilin Wang, Lu Zhang, and Ilya A. Shkrob
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Materials science ,Conductometry ,02 engineering and technology ,Electrolyte ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Thermal diffusivity ,Electrochemistry ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Ion ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Ionic liquid ,Materials Chemistry ,Ionic conductivity ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy - Abstract
Nonaqueous redox flow batteries use liquid electrolytes containing redox-active organic molecules (redoxmers) as their energy storage medium. To maximize energy density, the redoxmer concentration needs to be maximized while maintaining low viscosity and high ionic conductivity. During charge, a redoxmer molecule pairs with an ion in the electrolyte while another ion migrates across the membrane to maintain electric neutrality. In a crowded electrolyte, this reconstitution changes physical and chemical properties of the solution. To explore these behaviors, a phenothiazine redoxmer fully miscible with acetonitrile was used, and electrochemical charge was mimicked by chemical oxidation. The solutions were examined using small-angle X-ray scattering, nuclear magnetic resonance, and conductometry and modeled using classical molecular dynamics. Our study indicates that physical and structural properties of redoxmer solutions in both states of charge make it exceedingly difficult to increase the redoxmer concentrations over 2 M at any temperature without compromising dynamic properties of such solutions. The cause for this limitation is proximity to a gel-like regime in which fluidity, diffusivity, and ionic conductivity exponentially decrease with increasing concentration. This tendency is compounded by non-Arrhenius behavior of the electrolyte: a small increase in the concentration outruns gains in fluidity and conductivity at a higher temperature. Thus the properties of crowded electrolytes generally make it impossible to operate when gel-like behavior sets in. Pushing the redoxmer concentration to 2.5–3 M might be possible for small redoxmer molecules, but it would require the use of ionic liquid electrolytes at 340–360 K.
- Published
- 2021
16. A stable two-electron-donating phenothiazine for application in nonaqueous redox flow batteries
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Jeffrey A. Kowalski, Corrine F. Elliott, Chad Risko, N. Harsha Attanayake, Jarrod D. Milshtein, Fikile R. Brushett, Naijao Zhang, Aman Preet Kaur, Susan A. Odom, Sean Parkin, Matthew D. Casselman, and Subrahmanyam Modekrutti
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Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Electron ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Nitrogen ,Redox ,Small molecule ,0104 chemical sciences ,Dication ,Delocalized electron ,chemistry.chemical_compound ,chemistry ,Radical ion ,Phenothiazine ,General Materials Science ,0210 nano-technology - Abstract
Stable electron-donating organic compounds are of interest for numerous applications that require reversible electron-transfer reactions. Although many organic compounds are stable one-electron donors, removing a second electron from a small molecule to form its dication usually leads to rapid decomposition. For cost-effective electrochemical energy storage utilizing organic charge-storage species, the creation of high-capacity materials requires stabilizing more charge whilst keeping molecular weights low. Here we report the simple modification of N-ethylphenothiazine, which is only stable as a radical cation (not as a dication), and demonstrate that introducing electron-donating methoxy groups para to nitrogen leads to dramatically improved stability of the doubly oxidized (dication) state. Our results reveal that this derivative is more stable than an analogous compound with substituents that do not allow for further charge delocalization, rendering it a promising scaffold for developing atom-efficient, two-electron donors.
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- 2017
17. High current density, long duration cycling of soluble organic active species for non-aqueous redox flow batteries
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Subrahmanyam Modekrutti, Chad Risko, Jarrod D. Milshtein, Peter L. Zhang, Matthew D. Casselman, Corrine F. Elliott, Sean Parkin, Fikile R. Brushett, Aman Preet Kaur, N. Harsha Attanayake, Jeffrey A. Kowalski, and Susan A. Odom
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Aqueous solution ,Renewable Energy, Sustainability and the Environment ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,7. Clean energy ,01 natural sciences ,Pollution ,Redox ,0104 chemical sciences ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,Chemical engineering ,chemistry ,Phenothiazine ,Electrode ,Environmental Chemistry ,Bulk electrolysis ,Cyclic voltammetry ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
Non-aqueous redox flow batteries (NAqRFBs) employing redox-active organic molecules show promise to meet requirements for grid energy storage. Here, we combine the rational design of organic molecules with flow cell engineering to boost NAqRFB performance. We synthesize two highly soluble phenothiazine derivatives, N-(2-methoxyethyl)phenothiazine (MEPT) and N-[2-(2-methoxyethoxy)ethyl]phenothiazine (MEEPT), via a one-step synthesis from inexpensive precursors. Synthesis and isolation of the radical-cation salts permit UV-vis decay studies that illustrate the high stability of these open-shell species. Cyclic voltammetry and bulk electrolysis experiments reveal the promising electrochemical properties of MEPT and MEEPT under dilute conditions. A high performance non-aqueous flow cell, employing interdigitated flow fields and carbon paper electrodes, is engineered and demonstrated; polarization and impedance studies quantify the cell's low area-specific resistance (3.2–3.3 Ω cm2). We combine the most soluble derivative, MEEPT, and its tetrafluoroborate radical-cation salt in the flow cell for symmetric cycling, evincing a current density of 100 mA cm−2 with undetectable capacity fade over 100 cycles. This coincident high current density and capacity retention is unprecedented in NAqRFB literature.
- Published
- 2016
18. Overcharge protection of lithium-ion batteries above 4 V with a perfluorinated phenothiazine derivative
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Aman Preet Kaur, Corrine F. Elliott, Chad Risko, Susan A. Odom, Matthew D. Casselman, and Sean Parkin
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Overcharge ,Phenothiazine derivative ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,0104 chemical sciences ,Ion ,chemistry.chemical_compound ,chemistry ,Phenothiazine ,General Materials Science ,Lithium ,Graphite ,0210 nano-technology ,Derivative (chemistry) - Abstract
Electron-withdrawing substituents are introduced onto the phenothiazine core to raise its oxidation potential for use as a redox shuttle in high-voltage lithium-ion batteries. A perfluorinated derivative oxidizes at 4.3 V vs. Li+/0, and functions for ca. 500 h of 100% overcharge in LiNi0.8Co0.15Al0.05O2/graphite coin cells at a charging rate of C/10.
- Published
- 2016
19. Carbonic anhydrase mimics for enhanced CO2 absorption in an amine-based capture solvent
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Felice C. Lightstone, Sean Parkin, David A. Miller, Rachael A. Kelsey, Cameron A. Lippert, Yue Yang, Kunlei Liu, Joe E. Remias, Susan A. Odom, and Kun Liu
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Models, Molecular ,Phenanthroline ,Imine ,Ligands ,010402 general chemistry ,01 natural sciences ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Biomimetic Materials ,Carbonic anhydrase ,Polymer chemistry ,Organic chemistry ,Amines ,Carbonic Anhydrases ,chemistry.chemical_classification ,biology ,010405 organic chemistry ,Ligand ,Water ,Carbon Dioxide ,0104 chemical sciences ,Solvent ,Enzyme ,chemistry ,Solvents ,biology.protein ,Amine gas treating ,Adsorption ,Phenanthrolines - Abstract
Two new small-molecule enzyme mimics of carbonic anhydrase were prepared and characterized. These complexes contain the salen-like ligand bis(hydroxyphenyl)phenanthroline. This ligand is similar to the salen-type ligands previously incorporated into carbonic anhydrase mimics but contains no hydrolyzable imine groups and therefore serves as a promising ligand scaffold for the synthesis of a more robust CO2 hydration catalyst. These homogeneous catalysts were investigated for CO2 hydration in concentrated primary amine solutions through which a dilute CO2 (14%) fluid stream was flowed and showed exceptional activity for increased CO2 absorption rates.
- Published
- 2016
20. Overcharge Performance of 3,7-Bis(trifluoromethyl)-N-ethylphenothiazine at High Concentration in Lithium-Ion Batteries
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Aman Preet Kaur, Corrine F. Elliott, Selin Ergun, and Susan A. Odom
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High concentration ,Overcharge ,Trifluoromethyl ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,chemistry.chemical_compound ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Materials Chemistry ,Electrochemistry ,Lithium - Published
- 2015
21. Cathode candidates for zinc-based thermal-electrochemical energy storage
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Stephen Manek, Nicolas E. Holubowitch, James Landon, Susan A. Odom, Kunlei Liu, and Cameron A. Lippert
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Renewable Energy, Sustainability and the Environment ,Chemistry ,Inorganic chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Zinc ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Energy storage ,Cathode ,0104 chemical sciences ,law.invention ,Fuel Technology ,Nuclear Energy and Engineering ,law ,Thermal ,0210 nano-technology ,Electrochemical energy storage - Published
- 2015
22. A Highly Soluble Organic Catholyte for Non-Aqueous Redox Flow Batteries
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Aman Preet Kaur, Selin Ergun, Corrine F. Elliott, Nicolas E. Holubowitch, and Susan A. Odom
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Electron transfer ,Overcharge ,chemistry.chemical_compound ,General Energy ,Trifluoromethyl ,Aqueous solution ,Radical ion ,chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Lithium ,Solubility ,Redox - Abstract
A phenothiazine derivative with high solubility in carbonate solvents containing lithium salts showed extensive overcharge protection and, as a result, has been evaluated as a catholyte for non-aqueous redox flow batteries. We report the testing of 3,7-bis(trifluoromethyl)-N-ethylphenothiazine as a catholyte and 2,3,6-trimethylquinoxaline as the anolyte in redox flow batteries containing 0.05, 0.15, and 0.35 M active material and found the longest capacity retention over about 60 cycles at 0.15 M. To our knowledge, this is the most soluble catholyte candidate with a robust radical cation.
- Published
- 2015
23. Beyond the Hammett Effect: Using Strain to Alter the Landscape of Electrochemical Potentials
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Susan A. Odom, Peter L. Zhang, Sean Parkin, Subrahmanyam Modekrutti, Chad Risko, Matthew D. Casselman, and Corrine F. Elliott
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Steric effects ,Strain (chemistry) ,Chemistry ,Relaxation (NMR) ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,Photochemistry ,01 natural sciences ,Redox ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Organic chemistry ,Reductive decomposition ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
The substitution of sterically bulky groups at precise locations along the periphery of fused-ring aromatic systems is demonstrated to increase electrochemical oxidation potentials by preventing relaxation events in the oxidized state. Phenothiazines, which undergo significant geometric relaxation upon oxidation, are used as fused-ring models to showcase that electron-donating methyl groups, which would generally be expected to lower oxidation potential, can lead to increased oxidation potentials when used as the steric drivers. Reduction events remain inaccessible through this molecular design route, a critical characteristic for electrochemical systems where high oxidation potentials are required and in which reductive decomposition must be prevented, as in high-voltage lithium-ion batteries. This study reveals a new avenue to alter the redox characteristics of fused-ring systems that find wide use as electroactive elements across a number of developing technologies.
- Published
- 2017
24. Controlling Oxidation Potentials in Redox Shuttle Candidates for Lithium-Ion Batteries
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Selin Ergun, Aman Preet Kaur, Corrine F. Elliott, Sean Parkin, and Susan A. Odom
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Overcharge ,Chemistry ,Inorganic chemistry ,Battery electrolyte ,chemistry.chemical_element ,High voltage ,Redox ,Cathode ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Ion ,General Energy ,law ,Lithium ,Physical and Theoretical Chemistry ,Voltage - Abstract
Overcharge, a condition in which cell voltage rises to undesirably high potentials, can be prevented in lithium-ion batteries by incorporating redox shuttles into the battery electrolyte. Although extensive overcharge protection has been demonstrated in batteries with LiFePO4 cathodes, the redox shuttles that work in these batteries are incompatible with higher voltage cathodes. Designing stable additives with higher oxidation potentials is necessary to protect high voltage batteries from overcharge. Toward that goal, we synthesized diarylamines with varied structures, including fused heteroaromatic ring systems and electron-withdrawing substituents. We found that trends in oxidation potentials correlated with those in calculated adiabatic ionization potentials. Some diarylamine derivatives protected batteries from overcharge with varying degrees of success.
- Published
- 2014
25. 3,7-Bis(trifluoromethyl)-N-ethylphenothiazine: a redox shuttle with extensive overcharge protection in lithium-ion batteries
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Corrine F. Elliott, Aman Preet Kaur, Selin Ergun, and Susan A. Odom
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Overcharge ,chemistry.chemical_compound ,Trifluoromethyl ,chemistry ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,chemistry.chemical_element ,General Materials Science ,Lithium ,General Chemistry ,Graphite ,Redox ,Ion - Abstract
3,7-Bis(trifluoromethyl)-N-ethylphenothiazine (BCF3EPT) was evaluated as a redox shuttle for overcharge protection in lithium-ion batteries. Constant-charging experiments were performed to compare the compound to 1,4-di-tert-butyl-2,5-dimethoxybenzene and N-ethylphenothiazine. BCF3EPT showed significantly longer overcharge protection when compared to either benchmark at the same concentrations in LiFePO4/graphite batteries.
- Published
- 2014
26. Improving carbon capture from power plant emissions with zinc- and cobalt-based catalysts
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Sean Parkin, Kun Liu, Susan A. Odom, Cameron A. Lippert, Joseph E. Remias, Kunlei Liu, Christine M. Brandewie, and Moushumi Sarma
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Primary (chemistry) ,chemistry ,Power station ,Homogeneous ,Inorganic chemistry ,chemistry.chemical_element ,Organic chemistry ,Amine gas treating ,Zinc ,Cobalt ,Catalysis - Abstract
We report homogeneous catalysts that are soluble and stable in primary amine-based CO2 capture solvents. The zinc(II) and cobalt(III) complexes, which contain electron-donating multi-dentate anionic ligands, perform catalytic CO2 hydration at unparalleled observed rates under conditions conducive to industrial post-combustion carbon capture processes.
- Published
- 2014
27. A fast, inexpensive method for predicting overcharge performance in lithium-ion batteries
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Susan A. Odom, Pramod Prasad Poudel, Sean Parkin, and Selin Ergun
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Battery (electricity) ,Overcharge ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,chemistry.chemical_element ,Electrolyte ,Pollution ,Redox ,Anode ,Nuclear Energy and Engineering ,chemistry ,Radical ion ,Environmental Chemistry ,Lithium ,Cyclic voltammetry - Abstract
A variety of mechanisms lead to the failure of lithium-ion batteries. One is overcharge, a condition in which a battery's voltage rises above its designed end-of-charge potential. Electrolyte additives called redox shuttles limit cell potential by preferentially oxidizing, and cycling between the cathode and anode in their radical cation and neutral forms. Currently, testing requires coin cell assembly and repeated cycling, which can be an expensive and time consuming process. It is commonly accepted that degradation of the radical cation form of a redox shuttle leads to overcharge protection failure. We thus studied the stability of the radical cation forms of a series of redox shuttle additives to determine if there is a correlation between radical cation stability and the number of cycles of overcharge protection. While the reversibility of oxidations in cyclic voltammetry did not correlate to trends in overcharge performance, results from both UV-vis and electron paramagnetic resonance spectroscopy showed a correlation between stability and overcharge protection. Our results reveal trends within a few hours for what otherwise takes months of battery cycling to determine, providing a fast and relatively inexpensive method for predicting redox shuttle performance.
- Published
- 2014
28. A Less Basic, Basic Organic Flow Battery
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Susan A. Odom
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Chemistry ,Potassium ,Inorganic chemistry ,Joule ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Flow battery ,Anthraquinone ,0104 chemical sciences ,Quinone ,chemistry.chemical_compound ,General Energy ,Ferrocyanide ,Solubility ,0210 nano-technology ,Derivative (chemistry) - Abstract
In this issue of Joule, Michael Aziz, Roy Gordon, Alan Aspuru-Guzik, and colleagues report a new derivative of anthraquinone that exhibits greater solubility and stability in basic solutions. Cells operated at ambient temperatures at pH 12 that contain the new quinone and potassium ferri-/ferrocyanide show remarkably improved stability.
- Published
- 2018
29. 3-Hexylthiophene as a Stabilizing Additive for High Voltage Cathodes in Lithium-Ion Batteries
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Jeffrey S. Moore, Khalil Amine, Rohit Bhargava, Huiming Wu, Hadi Tavassol, Matthew V. Schulmerich, Susan A. Odom, Andrew A. Gewirth, and Ali Abouimrane
- Subjects
Supercapacitor ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electrical engineering ,chemistry.chemical_element ,High voltage ,Nanotechnology ,Condensed Matter Physics ,Cathode ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,law.invention ,chemistry ,law ,Materials Chemistry ,Electrochemistry ,Lithium ,Nanoarchitectures for lithium-ion batteries ,business - Published
- 2012
30. Tuning Delocalization in the Radical Cations of 1,4-Bis[4-(diarylamino)styryl]benzenes, 2,5-Bis[4-(diarylamino)styryl]thiophenes, and 2,5-Bis[4-(diarylamino)styryl]pyrroles through Substituent Effects
- Author
-
Veaceslav Coropceanu, Jean-Luc Brédas, Chad Risko, Seth R. Marder, Stephen Barlow, Luca Beverina, Susan A. Odom, Shijun Zheng, Barlow, S, Risko, C, Odom, S, Zheng, S, Coropceanu, V, Beverina, L, Bredas, J, and Marder, S
- Subjects
delocalization ,Aryl ,Diabatic ,Substituent ,General Chemistry ,Photochemistry ,Biochemistry ,Catalysis ,law.invention ,Crystallography ,chemistry.chemical_compound ,Delocalized electron ,Colloid and Surface Chemistry ,chemistry ,law ,Molecular orbital ,Electron paramagnetic resonance - Abstract
Radical cations have been generated for 10 bis[4-(diarylamino)styryl]arenes and heteroarenes to investigate the effect of the electron-richness of the terminal groups and of the bridging (hetero)arene on delocalization. The intervalence charge-transfer bands of these radical cations vary from weak broad Gaussians, indicative of localized class-II mixed-valence species, to strong relatively narrow asymmetric bands, characteristic of delocalized class-III bis(diarylamino) species, to narrow symmetric bands in cases where the bridge contribution to the singly occupied molecular orbital is largest. Hush analysis of these bands yields estimates of the electronic coupling varying from 480 cm -1 (electron-poor bridge, most electron-rich terminal aryl groups) to 1000 cm -1 (electron-rich bridge, least electron-rich termini) if the diabatic electron-transfer distance, R ab, is equated to the N-N separation. Computational and electron spin resonance (ESR) evidence for displacement of the diabatic states into the bridge (reduced R ab) suggests that these values are underestimates and that even more variation is to be expected through the series. Several dications have also been studied. The vis-NIR absorption of the dication of (E,E)-1,4-bis{4-[bis(4-n-butoxyphenyl) amino]styryl}-2,5-dicyanobenzene is seen at an energy similar to that of the strongest band in the spectrum of the corresponding weakly coupled monocation, with approximately twice the absorptivity, and its ESR spectrum suggests essentially noninteracting radical centers. In contrast, the electronic spectra of class-III monocations show no clear relationship to those of the corresponding dications, which ESR reveals to be singlet species. © 2012 American Chemical Society.
- Published
- 2012
31. Visual Indication of Mechanical Damage Using Core–Shell Microcapsules
- Author
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Scott R. White, Nancy R. Sottos, Jeffrey S. Moore, Sarut Chayanupatkul, Susan A. Odom, Aaron C. Jackson, and Alexander Prokup
- Subjects
Materials science ,genetic structures ,Conjugated system ,Polyacetylene ,chemistry.chemical_compound ,chemistry ,Scratch ,Ring-opening metathesis polymerisation ,General Materials Science ,Thermal stability ,sense organs ,Thin film ,Composite material ,computer ,Prepolymer ,computer.programming_language ,Polyurethane - Abstract
We report a new core-shell microcapsule system for the visual detection of mechanical damage. The core material, 1,3,5,7-cyclooctatetraene, is a conjugated cyclic olefin and a precursor to intensely colored polyacetylene. A combination of poly(urea-formaldehyde) and polyurethane is required to effectively encapsulate the volatile core material. Increasing the outer shell wall thickness and including a core-side prepolymer improves the thermal stability and free-flowing nature of these capsules, which tend to leach and rupture with thinner shell walls. Capsules ruptured in the presence of the Grubbs-Love ruthenium catalyst show immediate color change from nearly colorless to red-orange and dark purple over time, and color change in thin films resulted from scratch damage.
- Published
- 2011
32. Triggered Release from Polymer Capsules
- Author
-
Jeffrey S. Moore, Aaron P. Esser-Kahn, Scott R. White, Nancy R. Sottos, and Susan A. Odom
- Subjects
Inorganic Chemistry ,chemistry.chemical_classification ,Polymers and Plastics ,Chemistry ,Covalent bond ,Organic Chemistry ,Drug delivery ,Materials Chemistry ,Biophysics ,Triggered release ,Nanotechnology ,Polymer ,Controlled release - Abstract
Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.
- Published
- 2011
33. Restoration of Conductivity with TTF-TCNQ Charge-Transfer Salts
- Author
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Mary M. Caruso, Jeffrey S. Moore, Nancy R. Sottos, Scott R. White, Aaron D. Finke, Alexander Prokup, Joshua A. Ritchey, Susan A. Odom, and John H. Leonard
- Subjects
chemistry.chemical_classification ,Diffraction ,endocrine system ,Materials science ,Salt (chemistry) ,Nanotechnology ,respiratory system ,Conductivity ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry ,Chemical engineering ,Self-healing ,Electrode ,Electrochemistry ,Fourier transform infrared spectroscopy ,Electrical conductor - Abstract
The formation of the conductive TTF-TCNQ (tetrathiafulvalene–tetracyanoquinodimethane) charge-transfer salt via rupture of microencapsulated solutions of its individual components is reported. Solutions of TTF and TCNQ in various solvents are separately incorporated into poly(urea-formaldehyde) core–shell microcapsules. Rupture of a mixture of TTF-containing microcapsules and TCNQ-containing microcapsules results in the formation of the crystalline salt, as verified by FTIR spectroscopy and powder X-ray diffraction. Preliminary measurements demonstrate the partial restoration of conductivity of severed gold electrodes in the presence of TTF-TCNQ derived in situ. This is the first microcapsule system for the restoration of conductivity in mechanically damaged electronic devices in which the repairing agent is not conductive until its release.
- Published
- 2010
34. Electronic Properties of the 2,6-Diiododithieno[3,2-b:2′,3′-d]thiophene Molecule and Crystal: A Joint Experimental and Theoretical Study
- Author
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Tissa Sajoto, Stephen Barlow, Tatiana V. Timofeeva, Tiffany L. Kinnibrugh, Seth R. Marder, Eung-Gun Kim, Veaceslav Coropceanu, Jean-Luc Brédas, Susan A. Odom, and Roel S. Sánchez-Carrera
- Subjects
Materials science ,Surfaces, Coatings and Films ,Pentacene ,chemistry.chemical_compound ,Crystallography ,Effective mass (solid-state physics) ,chemistry ,Computational chemistry ,Materials Chemistry ,Thiophene ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,Cyclic voltammetry ,Spectroscopy ,Single crystal - Abstract
The electronic properties of the 2,6-diiododithieno[3,2-b:2',3'-d] thiophene molecule and crystal are investigated by means of UV-vis spectroscopy, cyclic voltammetry, X-ray crystallography, and density functional theory. The experimental and calculated properties of the compound are compared to those exhibited by the parent molecule, dithieno[3,2-b:2',3'-d]thiophene. Quantum-chemical studies of the 2,6-diiododithieno[3,2-b:2',3'-d]thiophene crystal suggest uniaxial hole-transport character with an effective mass of about 2m(0), comparable to that in the pentacene single crystal.
- Published
- 2009
35. Linear and Nonlinear Spectroscopy of a Porphyrin−Squaraine−Porphyrin Conjugated System
- Author
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Harry L. Anderson, Gero Nootz, Jonathan D. Matichak, Seth R. Marder, Lazaro A. Padilha, David J. Hagan, Olga V. Przhonska, Eric W. Van Stryland, Scott Webster, Stephen Barlow, Davorin Peceli, Susan A. Odom, Alexei D. Kachkovski, and Honghua Hu
- Subjects
Chemistry ,Quantum yield ,Conjugated system ,Nanosecond ,Photochemistry ,Porphyrin ,Fluorescence ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,Intramolecular force ,Materials Chemistry ,Physical and Theoretical Chemistry ,Absorption (electromagnetic radiation) ,Excitation - Abstract
The linear and nonlinear absorption properties of a squaraine-bridged porphyrin dimer (POR-SQU-POR) are investigated using femto-, pico-, and nanosecond pulses to understand intramolecular processes, obtain molecular optical parameters, and perform modeling of the excited-state dynamics. The optical behavior of POR-SQU-POR is compared with its separate porphyrin and squaraine constituent moieties. Linear spectroscopic studies include absorption, fluorescence, excitation and emission anisotropy, and quantum yield measurements. Nonlinear spectroscopic studies are performed across a wide range (approximately 150 fs, approximately 25 ps, and approximately 5 ns) of pulsewidths and include two-photon absorption (2PA), single and double pump-probe, and Z-scan measurements with detailed analysis of excited-state absorption induced by both one- and two-photon absorption processes. The 2PA from the constituent moieties shows relatively small 2PA cross sections; below 10 GM (1 GM = 1 x 10(-50) cm4 s/photon) for the porphyrin constituent and below 100 GM for the squaraine constituent except near their one-photon resonances. In stark contrast, the composite POR-SQU-POR molecule shows 2PA cross sections greater than 10(3) GM over most of the spectral range from 850 to 1600 nm (the minimum value being 780 GM at 1600 nm). The maximum value is approximately 11,000 GM near the Nd:YAG laser wavelength of 1064 nm. This broad spectral range of large 2PA cross sections is unprecedented in any other molecular system and can be explained by intramolecular charge transfer. A theoretical quantum-chemical analysis in combination with different experimental techniques allows insight into the energy-level structure and origin of the nonlinear absorption behavior of POR-SQU-POR.
- Published
- 2009
36. Intramolecular Electron-Transfer Rates in Mixed-Valence Triarylamines: Measurement by Variable-Temperature ESR Spectroscopy and Comparison with Optical Data
- Author
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Sankaran Thayumanavan, Susan A. Odom, Kelly Lancaster, Stephen Barlow, Simon C. Jones, Seth R. Marder, Veaceslav Coropceanu, and Jean-Luc Brédas
- Subjects
Valence (chemistry) ,General Chemistry ,Atmospheric temperature range ,Photochemistry ,Biochemistry ,Catalysis ,law.invention ,chemistry.chemical_compound ,Electron transfer ,Crystallography ,Delocalized electron ,Colloid and Surface Chemistry ,chemistry ,law ,Intramolecular force ,Benzene ,Spectroscopy ,Electron paramagnetic resonance - Abstract
The electron spin resonance spectra of the radical cations of 4,4'-bis[di(4-methoxyphenyl)amino]tolane, E-4,4'-bis[di(4-methoxyphenyl)amino]stilbene, and E,E-1,4-bis{4-[di(4-methoxyphenyl)amino]styryl}benzene in dichloromethane exhibit five lines over a wide temperature range due to equivalent coupling to two 14N nuclei, indicating either delocalization between both nitrogen atoms or rapid intramolecular electron transfer on the electron spin resonance time scale. In contrast, those of the radical cations of 1,4-bis{4-[di(4-methoxyphenyl)amino]phenylethynyl}benzene and E,E-1,4-bis{4-[di(4-n-butoxyphenyl)amino]styryl}-2,5-dicyanobenzene exhibit line shapes that vary strongly with temperature, displaying five lines at room temperature and only three lines at ca. 190 K, indicative of slow electron transfer on the electron spin resonance time scale at low temperatures. The rates of intramolecular electron transfer in the latter compounds were obtained by simulation of the electron spin resonance spectra and display an Arrhenius temperature dependence. The activation barriers obtained from Arrhenius plots are significantly less than anticipated from Hush analyses of the intervalence bands when the diabatic electron-transfer distance, R, is equated to the N[symbol: see text]N distance. Comparison of optical and electron spin resonance data suggests that R is in fact only ca. 40% of the N[symbol: see text]N distance, while the Arrhenius prefactor indicates that the electron transfer falls in the adiabatic regime.
- Published
- 2009
37. Bis[bis-(4-alkoxyphenyl)amino] Derivatives of Dithienylethene, Bithiophene, Dithienothiophene and Dithienopyrrole: Palladium-Catalysed Synthesis and Highly Delocalised Radical Cations
- Author
-
Natalie J. Thompson, Jean-Luc Brédas, Kelly Lancaster, Veaceslav Coropceanu, Seth R. Marder, Stephen Barlow, Kelly M. Lefler, Luca Beverina, Susan A. Odom, Odom, S, Lancaster, K, Beverina, L, Lefler, K, Thompson, N, Coropceanu, V, Brédas, J, Marder, S, and Barlow, S
- Subjects
Radical ,Organic Chemistry ,microwave, radical cation, photonics ,chemistry.chemical_element ,General Chemistry ,Photochemistry ,Medicinal chemistry ,Catalysis ,chemistry.chemical_compound ,Radical ion ,chemistry ,Ferrocene ,Phenylene ,Thiophene ,Density functional theory ,Pyrrole ,Palladium - Abstract
Five diamines with thiophene-based bridges-(E)-1,2-bis-{5-[bis(4- butoxyphenyl)amino]-2-thienyljethylene (1), 5,5′-bis[bis(4-methoxyphenyl) amino]-2,2′-bithiophene (2), 2,6-bis[bis(4-butoxyphenyl)amino]dithieno[3, 2-b:2′,3′-d]thiophene (3), N-(4-tert-butylphenyl)-2,6-bis[bis(4- methoxyphenyl)amino]dithieno[3,2-b:2′,3′-d]pyrrole (4a) and N-tert-butyl-2,6-bis[bis(4-methoxyphenyl)amino]dithieno[3,2-b:2′, 3′-d]pyrrole (4b)-have been synthesised. The syntheses make use of the palladium(0)-catalysed coupling of brominated thiophene species with diarylamines, in some cases accelerated by microwave irradiation. The molecules all undergo facile oxidation, 4b being the most readily oxidised at about -0.4 V versus ferrocenium/ferrocene, and solutions of the corresponding radical cations were generated by addition of tris(4-bromophenyl)aminium hexachloroantimonate to the neutral species. The near-IR spectra of the radical cations show absorptions characteristic of symmetrical delocalised species (that is, class III mixed-valence species); analysis of these absorptions in the framework of Hush theory indicates strong coupling between the two amine redox centres, stronger than that observed in species with phenylenebased bridging groups of comparable length. The strong coupling can be attributed to high-lying orbitais of the thiophene-based bridging units. ESR spectroscopy indicates that the coupling constant to the amino nitrogen atoms is somewhat reduced relative to that in a stilbene-bridged analogue. The neutral species and the corresponding radical cations have been studied with the aid of density functional theory and time-dependent density functional theory. The DFT-calculated ESR parameters are in good agreement with experiment, while calculated spin densities suggest increased bridge character to the oxidation in these species relative to that in comparable species with phenylene-based bridges. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.
- Published
- 2007
38. A Highly Soluble Redox Shuttle with Superior Rate Performance in Overcharge Protection
- Author
-
Aman Preet Kaur, Matthew D. Casselman, Susan A. Odom, Corrine F. Elliott, and Selin Ergun
- Subjects
Electronegativity ,Overcharge ,chemistry.chemical_compound ,Trifluoromethyl ,chemistry ,Nitrogen atom ,Inorganic chemistry ,Battery electrolyte ,Solubility ,Redox ,Chemical reaction - Abstract
The demand for a stable and compatible redox shuttles for use in lithium-ion batteries has prompted us to explore strategies to tune and improve the properties of redox shuttles. We have studied over 50 new diarylamine derivatives synthesized in our laboratory including one compound in which we introduced trifluoromethyl groups (–CF3) at the positions para to the nitrogen atom in N-ethylphenothiazine (EPT). The high electronegativity of the CF3 group raises the oxidation potential, and its incorporation also significantly increases solubility in battery electrolyte. Here we report 3,7-bis(trifluoromethyl)-N-ethylphenothiazine (BCF3EPT) as a new redox shuttle, which we have observed to have the highest reported solubility in battery electrolyte of all redox shuttles that maintain extended overcharge performance. We have compared its performance with 1,3-di-tert-butyl-2,5-dimethoxybenzene (DBB), EPT, and other robust redox shuttles. In our hands, overcharge cycling of BCF3EPT far surpasses any reported redox shuttle, and – because it can be dissolved at higher concentrations – it tolerates faster charging rates than both DBB and EPT.
- Published
- 2015
39. On the Stability and Reactivity of Redox Shuttles in Their Neutral and Radical Cation Forms
- Author
-
Aman Preet Kaur, Naijao Zhang, Selin Ergun, Matthew D. Casselman, and Susan A. Odom
- Subjects
Electrode material ,Overcharge ,Radical ion ,Chemistry ,Reactivity (chemistry) ,Electrolyte ,Photochemistry ,Decomposition ,Chemical reaction ,Redox - Abstract
The performance of aromatic compounds as redox shuttles for overcharge protection in lithium-ion batteries is quite variable and is often difficult to predict. Redox shuttles may decompose in battery electrolyte in their neutral and radical cation forms, both of which are present during overcharge protection. While hundreds of compounds have been evaluated as redox shuttle candidates and a few have stood out as top performers, the reasons for increased stability over similar candidates with slightly different structures is often unclear, and the exploration of decomposition of redox shuttles has been severely limited, restricting our ability to design improved versions of redox shuttles that do not suffer from the same reactions in lithium-ion batteries. To better understand the stability and reactivity of redox shuttles (also relevant to the improvement of positive electrode materials in non-aqueous redox flow batteries) our research has focused on measuring the stability of neutral and oxidized forms of redox shuttle candidates as well as using a variety of spectroscopic methods to analyze the byproducts of decomposition, both from radical cations generated in model solvents and electrolytes from postmortem analysis of failed batteries.
- Published
- 2015
40. Persistent photo-excited conducting states in functionalized pentacene
- Author
-
John E. Anthony, David L. Eaton, Neven Biskup, David Graf, James S. Brooks, Eun Sang Choi, Takahisa Tokumoto, and Susan A. Odom
- Subjects
education.field_of_study ,business.industry ,Band gap ,Chemistry ,Mechanical Engineering ,Photoconductivity ,Relaxation (NMR) ,Population ,Metals and Alloys ,Condensed Matter Physics ,Photochemistry ,Electronic, Optical and Magnetic Materials ,Organic semiconductor ,Photoexcitation ,Pentacene ,chemistry.chemical_compound ,Mechanics of Materials ,Excited state ,Materials Chemistry ,Optoelectronics ,business ,education - Abstract
We report a study of long-lived photo-excited states in single crystals of functionalized forms of pentacene: 6,13-bis (triisopropylsilylethynyl) pentacene, 6,13-bis (triethylsilylethynyl) pentacene, and 6,13-bis (triethylgermylethynyl) pentacene, organic semiconductors with band gaps ≈1 eV. The relaxation rates are thermally activated, as determined from time and temperature-dependent measurements of the photo-conductivity after illumination. These states can be produced in a stable population at temperatures below 150 K. Hence, after low temperature illumination, thermally stimulated current (TSC) is observed as temperature increases. Trap energies associated with these states can be estimated by analysis of the TSC signal.
- Published
- 2005
41. Persistent photoexcited conducting states in functionalized pentacene
- Author
-
Eun Sang Choi, Takahisa Tokumoto, David Graf, James S. Brooks, Neven Biskup, John E. Anthony, Susan A. Odom, and D. L. Eaton
- Subjects
chemistry.chemical_classification ,education.field_of_study ,Materials science ,Band gap ,business.industry ,Photoconductivity ,Population ,General Physics and Astronomy ,Polymer ,Pentacene ,Organic semiconductor ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Excited state ,Optoelectronics ,business ,education ,Dark current - Abstract
We report a study of long-lived photoexcited states in single crystals of functionalized forms of pentacene: the 6,13-bis(triisopropylsilylethynyl)pentacene and the 6,13-bis(triethylsilylethynyl)pentacene. These materials are organic semiconductors with band gaps in the range ≈1eV. The relaxation rate of these states is thermally activated, as determined from time-and temperature-dependent measurements of the photoconductivity after illumination, and these states can be produced in a stable population at temperatures below 150K. Consequently, after the low-temperature illumination, thermally stimulated current (TSC) is observed in the dark current with an increasing temperature. Analysis of the TSC signal allows estimation of energies associated with the excited states. Possible mechanisms for the current associated with the photoexcited states are discussed, and preliminary iodine-doped studies of the material are also presented.
- Published
- 2004
42. Stable, Crystalline Acenedithiophenes with up to Seven Linearly Fused Rings
- Author
-
Sean Parkin, Marcia M. Payne, John E. Anthony, and Susan A. Odom
- Subjects
Crystal ,Crystallography ,Chemistry ,Organic Chemistry ,Organic chemistry ,Physical and Theoretical Chemistry ,Solubility ,Absorption (chemistry) ,Biochemistry ,Fluorescence ,Decomposition - Abstract
[structure: see text] We report the synthesis of a series of crystalline acenedithiophenes with up to seven linearly fused rings and silylethynyl substituents. These functional groups are designed to both improve solubility and enhance cofacial interactions in the solid. We discuss the crystal packing of these materials, as well as their physical properties such as oxidation potential, UV-vis absorption, fluorescence emission, and decomposition pathways.
- Published
- 2004
43. Transport and melt processing in functionalized pentacene with 'organic wire' connections
- Author
-
R. Vasic, James S. Brooks, John E. Anthony, Susan A. Odom, David Graf, O. H. Chung, and Takahisa Tokumoto
- Subjects
Morphology (linguistics) ,business.industry ,Carbon fibers ,General Physics and Astronomy ,Nanotechnology ,Electrical contacts ,Pentacene ,chemistry.chemical_compound ,PEDOT:PSS ,chemistry ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Photonics ,business - Abstract
We explore melt processing of functionalized pentacene for use in electronic and photonic devices. In parallel, the use of carbon fibers to make electrical contact to the melt-films is described. We discuss the morphology of the melted films which includes the appearance of dendritic growth, carbon fiber contacts to the films, and the temperature dependence of the carbon, PEDOT, and pentacene components of the various structures.
- Published
- 2004
44. Overcharge performance of 3,7-disubstituted N-ethylphenothiazine derivatives in lithium-ion batteries
- Author
-
Selin Ergun, Susan A. Odom, Sean Parkin, Corrine F. Elliott, and Aman Preet Kaur
- Subjects
Battery (electricity) ,Overcharge ,Materials science ,Metals and Alloys ,chemistry.chemical_element ,General Chemistry ,Combinatorial chemistry ,Redox ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Lithium - Abstract
3,7-Disubstituted N-ethylphenothiazine derivatives were synthesized as redox shuttle candidates for lithium-ion batteries. Battery cycling results show that three derivatives prevent overcharge.
- Published
- 2013
45. ChemInform Abstract: Triggered Release from Polymer Capsules
- Author
-
Jeffrey S. Moore, Susan A. Odom, Nancy R. Sottos, Aaron P. Esser-Kahn, and Scott R. White
- Subjects
chemistry.chemical_classification ,chemistry ,Covalent bond ,Drug delivery ,Biophysics ,Triggered release ,General Medicine ,Polymer ,Controlled release - Abstract
Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.
- Published
- 2011
46. Electronic and optical properties of 4H-cyclopenta[2,1-b:3,4-b']bithiophene derivatives and their 4-heteroatom-substituted analogues: a joint theoretical and experimental comparison
- Author
-
Seth R. Marder, Richard Mason, Yulia A. Getmanenko, Jean-Luc Brédas, Veaceslav Coropceanu, Kelly Lancaster, Stephen Barlow, and Susan A. Odom
- Subjects
chemistry.chemical_compound ,Crystallography ,chemistry ,Stereochemistry ,Heteroatom ,Phosphole ,Materials Chemistry ,Thiophene ,Physical and Theoretical Chemistry ,Electrochemistry ,Surfaces, Coatings and Films ,Pyrrole - Abstract
The electronic and optical properties of 2,6-dialkyl and 2,6-bis(5-alkyl-2-thienyl) derivatives of the fused-ring systems 4H-cyclopenta[2,1-b:3,4-b']bithiophene, 4,4-di-n-hexyl-4H-cyclopenta[2,1-b:3,4-b']bithiophene, 4H-cyclopenta[2,1-b:3,4-b']bithiophene-4-one, 4-alkyl and 4-aryldithieno[3,2-b:2',3'-d]pyrrole, 4-phenyldithieno[3,2-b:2',3'-d]phosphole, 4-phenyldithieno[3,2-b:2',3'-d]phosphole 4-oxide, dithieno[3,2-b:2',3'-d]thiophene, dithieno[3,2-b:2',3'-d]thiophene 4-oxide, and dithieno[3,2-b:2',3'-d]thiophene 4,4-dioxide have been compared to those of the analogous unbridged 5,5'-substituted 2,2'-bithiophene derivatives using electrochemistry, UV-visible absorption and emission spectroscopy, and DFT and TD-DFT calculations. The planarization in the fused-ring compounds means that the methylene-bridged cyclopentabithiophenes are more readily oxidized than their unbridged bithiophene analogues. In each case, the bridging group (X) lies on a nodal plane of the HOMO; accordingly, within each series of fused-ring compounds, electrochemical oxidation potentials and calculated ionization potentials depend primarily on the inductive donor/acceptor strength of the bridging group. On the other hand, significant LUMO coefficients can be found on X groups with π-donor or acceptor properties; accordingly, the electrochemical reduction potentials, calculated electron affinities, and the energies of the HOMO→LUMO optical transitions depend on both inductive and mesomeric donor and acceptor strengths. In particular, within the 2,6-bis(5-alkyl-2-thienyl) series, increasingly electron-withdrawing bridging groups lead to a bathochromic shift and weakening of the low-energy absorption band relative to that of methylene- or π-donor-bridged examples and also to a loss of vibronic structure, with the compound that has the strongest π-accepting bridge of those examined (X = CO) showing a particularly low-energy and weak band. The fluorescence of acceptor-bridged compounds exhibits greater Stokes shifts and a loss of vibronic structure relative to those of methylene- or π-donor-bridged analogues, with the carbonyl-bridged derivative showing no observable fluorescence. These results can be related to increasing localization of the LUMO on the core and toward the bridging group, leading to increased charge-transfer character for the first excited state. The radical cations of some examples have been generated by chemical oxidation and investigated using visible-NIR and ESR spectroscopy and DFT and TD-DFT calculations. The absorption spectra of the radical cations of the 2,6-bis(5-alkyl-2-thienyl) compounds are generally similar to those previously reported for quaterthiophene derivatives, while the hyperfine couplings obtained from ESR spectra are consistent with delocalization of the unpaired electron over both the core and terminal thienyl rings of the π system.
- Published
- 2010
47. Mechanically-induced chemical changes in polymeric materials
- Author
-
Nancy R. Sottos, Scott R. White, Qilong Shen, Susan A. Odom, Jeffrey S. Moore, Mary M. Caruso, and Douglas A. Davis
- Subjects
World Wide Web ,Thesaurus (information retrieval) ,Chemistry ,General Chemistry - Published
- 2009
48. Photophysical properties of an alkyne-bridged bis(zinc porphyrin)-perylene bis(dicarboximide) derivative
- Author
-
Michael R. Wasielewski, Eric W. Van Stryland, Harry L. Anderson, Lazaro A. Padilha, Shino Ohira, Scott Webster, Stephen Barlow, David J. Hagan, Jean-Luc Brédas, Chun Huang, Seth R. Marder, Richard F. Kelley, Susan A. Odom, Trenton R. Ensley, and Veaceslav Coropceanu
- Subjects
chemistry.chemical_classification ,chemistry.chemical_compound ,chemistry ,Radical ion ,Absorption spectroscopy ,Pyridine ,Molecule ,Alkyne ,Physical and Theoretical Chemistry ,Chromophore ,Absorption (electromagnetic radiation) ,Photochemistry ,Perylene - Abstract
We report the synthesis, electrochemistry, and photophysical properties of a new donor-acceptor-donor molecule in which the meso carbon atoms of two zinc porphyrin (POR) units are linked through ethynylene bridges to the 1,7-positions of a central perylene-3,4:9,10-bis(dicarboximide) (PDI). In contrast to previously studied systems incorporating POR and PDI groups, this alkyne-based derivative shows evidence of through-bond electronic coupling in the ground state; the new chromophore exhibits absorption features similar to those of its constituent parts as well as lower energy features (at wavelengths up to ca. 1000 nm), presumably arising from donor-acceptor interactions. Transient absorption measurements show that excitation at several visible and near-IR wavelengths results in the formation of an excited-state species with a lifetime of 290 ps in 1% (v/v) pyridine in toluene. The absorption spectrum of this species resembles the sum of the spectra for the chemically generated radical cation and radical anion of the chromophore. The chromophore shows moderate two-photon absorption cross sections (2000-7000 GM) at photon wavelengths close to the onset of its low-energy one-photon absorption feature.
- Published
- 2009
49. Synthesis and two-photon spectrum of a bis(porphyrin)-substituted squaraine
- Author
-
Lazaro A. Padilha, Eric W. Van Stryland, Seth R. Marder, Harry L. Anderson, Jean-Luc Brédas, Scott Webster, Stephen Barlow, Olga V. Przhonska, Gero Nootz, Jonathan D. Matichak, Honghua Hu, Susan A. Odom, Davorin Peceli, Sung-Jae Chung, Shino Ohira, David J. Hagan, and Alexei D. Kachkovski
- Subjects
Zinc porphyrin ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Two-photon excitation microscopy ,Absorption spectroscopy ,Chemistry ,Sonogashira coupling ,General Chemistry ,Chromophore ,Photochemistry ,Biochemistry ,Porphyrin ,Catalysis - Abstract
A chromophore in which zinc porphyrin donors are linked through their meso positions by ethynyl bridges to a bis(indolinylidenemethyl) squaraine core has been synthesized using Sonogashira coupling. The chromophore exhibits a two-photon absorption spectrum characterized by a peak cross section of 11,000 GM and, more unusually, also exhibits a large cross section of >780 GM over a photon-wavelength window 750 nm in width.
- Published
- 2009
50. Synthesis and photophysical properties of donor- and acceptor-substituted 1,7-bis(arylalkynyl)perylene-3,4:9,10-bis(dicarboximide)s
- Author
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David J. Hagan, Scott Webster, Stephen Barlow, Zesheng An, Eric W. Van Stryland, Michael R. Wasielewski, Susan A. Odom, Jie Fu, Lazaro A. Padilha, Richard F. Kelley, Xuan Zhang, Chun Huang, and Seth R. Marder
- Subjects
chemistry.chemical_compound ,Absorption edge ,chemistry ,Aryl ,Alkoxy group ,Sonogashira coupling ,Amine gas treating ,Physical and Theoretical Chemistry ,Chromophore ,Photochemistry ,Acceptor ,Perylene - Abstract
A series of 1,7-bis(arylethynyl)-N,N'-bis[2,6-diisopropylphenyl]perylene-3,4:9,10-bis(dicarboximide)s has been obtained from Sonogashira coupling of the 1,7-dibromoperylene-3,4:9,10-bis(dicarboximide) with p-substituted phenylacetylenes in which the p-substituents include pi-donors (dialkylamino, diarylamino, p-(diarylamino)phenyl, alkoxy) and pi-acceptors (diarylboryl, p-(diarylboryl)phenyl). The bis(arylethynyl)-substituted chromophores all show two reversible molecular reductions and are all slightly more readily reduced than unsubstituted perylene-3,4:9,10-bis(dicarboximide)s with the electrochemical potentials being rather insensitive to the pi-donor or acceptor nature of the aryl group. The amine derivatives also show reversible molecular oxidations. The UV-vis spectra of the chromophores with alkoxy and boryl substituents show red-shifted absorptions relative to unsubstituted perylene diimides with discernible vibronic structure. In contrast, the lowest energy absorptions of the amino derivatives are broad and structureless, suggesting donor-to-acceptor charge-transfer character. Transient absorption spectra for the amine derivatives were interpreted in terms of ultrafast charge separation, followed by charge recombination on a time scale of ca. 80-2000 ps. Two compounds were also synthesized in which an additional stronger, but more weakly coupled, donor group is linked by a nonconjugated bridge to the p-amine donor, to investigate the effect on the charge recombination lifetimes; however, the lifetimes of the charge-separated states, ca. 150 and 1000 ps, were within the range observed for the simple amine systems. Finally, the two-photon absorption properties of three bis(arylethynyl)-substituted derivatives were investigated, along with those of 1,7-di(pyrrolidin-1-yl)-N,N'-bis[2,6-diisopropylphenyl]perylene-3,4:9,10-bis(dicarboximide). As with other perylene-3,4:9,10-bis(dicarboximide)s and related species, strong two-photon absorption (1000 GM) was observed for three of these species close to the one-photon absorption edge; however, an additional feature (100-500 GM) was also observed at longer wavelength. An example with (p-aminophenyl)ethylnyl substituents showed a qualitatively different two-photon spectrum with a cross-section500 GM being observed over a broad wavelength range.
- Published
- 2009
Catalog
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