Eric Bohannan - Academia.edu (original) (raw)

Papers by Eric Bohannan

Research paper thumbnail of The Redox Chemistry of 4-Benzoyl- N- methylpyridinium Cations in Acetonitrile with and without Proton Donors:  The Role of Hydrogen Bonding

The Journal of Physical Chemistry B, 2001

In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated... more In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated (∆E 1/2 ∼ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence suggest that the positive shift of the second wave is due to hydrogen bonding between the two-electron reduced form of the ketone and the proton donors. While the one-electron reduction product is stable both in the presence and in the absence of the weak-acid proton donors, the two-electron reduction wave is reversible only in the time scale of cyclic voltammetry. Interestingly, at longer times, the hydrogen bonded adduct reacts further giving nonquaternized 4-benzoylpyridine and 4-(R-hydroxybenzyl)pyridine as the two main terminal products. In the presence of stronger acids, such as acetic acid, the second wave merges quickly with the first, producing an irreversible two-electron reduction wave. The only terminal product in this case is the quaternized 4-(Rhydroxybenzyl)-N-methylpyridinium cation. Experimental evidence points toward a common mechanism for the formation of the nonquaternized products in the presence of weaker acids and the quaternized product in the presence of CH 3 CO 2 H.

Research paper thumbnail of ChemInform Abstract: Electrodeposition of Co x Fe 3-x O 4 Epitaxial Films and Superlattices

ChemInform, 2013

ABSTRACT CoxFe3-xO4 (0 < x < 1) thin films are prepared by a one-step electrodeposi... more ABSTRACT CoxFe3-xO4 (0 < x < 1) thin films are prepared by a one-step electrodeposition from alkaline Fe3+- and Co2+-triethanolamine solutions.

Research paper thumbnail of The Redox Chemistry of 4-Benzoyl- N- methylpyridinium Cations in Acetonitrile with and without Proton Donors:  The Role of Hydrogen Bonding

The Journal of Physical Chemistry B, 2001

In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated... more In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated (∆E 1/2 ∼ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence suggest that the positive shift of the second wave is due to hydrogen bonding between the two-electron reduced form of the ketone and the proton donors. While the one-electron reduction product is stable both in the presence and in the absence of the weak-acid proton donors, the two-electron reduction wave is reversible only in the time scale of cyclic voltammetry. Interestingly, at longer times, the hydrogen bonded adduct reacts further giving nonquaternized 4-benzoylpyridine and 4-(R-hydroxybenzyl)pyridine as the two main terminal products. In the presence of stronger acids, such as acetic acid, the second wave merges quickly with the first, producing an irreversible two-electron reduction wave. The only terminal product in this case is the quaternized 4-(Rhydroxybenzyl)-N-methylpyridinium cation. Experimental evidence points toward a common mechanism for the formation of the nonquaternized products in the presence of weaker acids and the quaternized product in the presence of CH 3 CO 2 H.

Research paper thumbnail of X-ray characterization of as-deposited, epitaxial films of Bi(012) on Au(111)

Surface Science, 2006

Electrodeposition is used to produce epitaxial single-crystal films on Au(1 1 1) substrates witho... more Electrodeposition is used to produce epitaxial single-crystal films on Au(1 1 1) substrates without annealing or other post-deposition modification. X-ray techniques show that the Bi(0 1 2) plane is parallel to the underlying Au(1 1 1) surface, and the azimuthal orientation of the films is determined. Combination of the X-ray data with in situ scanning tunneling microscopy (STM) images suggests a common growth mode from the first few layers up to thick films.

Research paper thumbnail of Epitaxial Electrodeposition of Prussian Blue Thin Films on Single-Crystal Au(110)

Journal of the American Chemical Society, 2003

Research paper thumbnail of The effects of high levels of vitamin E on the progression of atherosclerosis in the Watanabe heritable hyperlipidemic rabbit

The Journal of Nutritional Biochemistry, 1993

Watanabe rabbits (5-6 months of age) were divided into two groups (seven each). One group was fed... more Watanabe rabbits (5-6 months of age) were divided into two groups (seven each). One group was fed standard Purina Rabbit Chow and the second was fed the same diet supplemented with 2000 mg/kg diet vitamin E. (Purina Rabbit Chow contains about 30 rag vitamin E/kg diet). After 9 months, the rabbits were sacrificed and plasma lipids were determined, and the area of plaque involvement in the aortas was measured. The extent of plaque formation (percentage of the total surface covered with fatty streaks) was not significantly different in the two groups. However, there were differences observed in plasma lipids. Plasma total cholesterol, low density lipoprotein cholesterol, and triglyceride levels were 20-30% lower in the vitamin E-fed group. Also, the concentration of cholesterol in the lesions of the aortic arch was about25% lower in the vitamin E-fed group. These results indicate that high levels of vitamin E may have a beneficial effect on lowering plasma lipids observed in hyperlipidemia. (J. Nutr. Biochem. 4:651-654, 1993.)

Research paper thumbnail of Self-assembly and catalytic properties of 1,1′-bridged-2,2′-dipyridinium amphiphiles

Journal of Electroanalytical Chemistry, 1998

An electrochemical and computational study of a series of three 4-methyl-4%-nonadecyl-1,1%-bridge... more An electrochemical and computational study of a series of three 4-methyl-4%-nonadecyl-1,1%-bridged-2,2%-dipyridinium ions is reported. In 0.1 M KCl these ions self-assemble on glassy carbon to form a close-packed monomolecular layer. Incorporation of perchlorate into the film by counterion exchange results in enhanced film stability and limiting surface coverages of ca. 1.7 × 10 − 10 mol cm − 2 . As the 1,1%-bridge length is increased from two to four methylene groups, the reversible one-electron reduction potential of the dipyridinium head group decreases from − 499 to − 833 mV vs. AgAgCl0.1 M KCl. These relatively negative reduction potentials make adsorbed 1,1%-bridged-2,2%-dipyridinium amphiphiles powerful immobilized reductants in aqueous solution. The catalytic potency of these amphiphiles is demonstrated by catalyzing the reduction of ethyl 3-benzoyl acrylate and artemisinin.

Research paper thumbnail of Evidence that Monochloramine Disinfectant Could Lead to Elevated Pb Levels in Drinking Water

Environmental Science & Technology, 2006

Research paper thumbnail of Enantiospecific Electrodeposition of Chiral CuO Films from Copper(II) Complexes of Tartaric and Amino Acids on Single-Crystal Au(001)

Chemistry of Materials, 2004

... Surface Chirality of CuO Thin Films. Roland Widmer, Franz-Josef Haug, Pascal Ruffieux, Oliver... more ... Surface Chirality of CuO Thin Films. Roland Widmer, Franz-Josef Haug, Pascal Ruffieux, Oliver Gröning, Michael Bielmann, Pierangelo Gröning, and Roman Fasel. Journal of the American Chemical Society 2006 128 (43), 14103-14108. Surface Chirality of CuO Thin Films. ...

Research paper thumbnail of Epitaxial Electrodeposition of Zinc Oxide Nanopillars on Single-Crystal Gold

Chemistry of Materials, 2001

ZnO nanopillars have been electrodeposited epitaxially onto Au(111), Au(110) and Au(100) single-c... more ZnO nanopillars have been electrodeposited epitaxially onto Au(111), Au(110) and Au(100) single-crystal substrates. The nanopillars grow with the same [0001] out-of-plane orientation on all three substrates. The in-plane orientation was probed by X-ray pole figure analysis. ...

Research paper thumbnail of Epitaxial Electrodeposition of High-Aspect-Ratio Cu 2 O(110) Nanostructures on InP(111)

Chemistry of Materials, 2005

ABSTRACT

Research paper thumbnail of Epitaxial Electrodeposition of Copper(I) Oxide on Single-Crystal Gold(100)

Chemistry of Materials, 1999

... Application of current densities higher than about 0.1 mA/cm 2 in this solution gives rise to... more ... Application of current densities higher than about 0.1 mA/cm 2 in this solution gives rise to oscillations in the potential coincident with the deposition of a Cu/Cu 2 O layered nanostructure on the ... The effect of TiO2/Cu2O ... ... Electrochemical Deposition of Copper(I) Oxide Films. ...

Research paper thumbnail of Shape Control in Epitaxial Electrodeposition:  Cu 2 O Nanocubes on InP(001)

Chemistry of Materials, 2003

... 11) Hodes, G. Electrochemistry of Nanomaterials ... Electrochemical Deposition of Semiconduct... more ... 11) Hodes, G. Electrochemistry of Nanomaterials ... Electrochemical Deposition of Semiconductor Oxides on Reduced Graphene Oxide-Based Flexible, Transparent, and ... Synthesis, Shape Evolution, and Photocatalytic Activity of Truncated Cuprous Oxide Octahedron Microcrystals ...

Research paper thumbnail of Electrodeposition of Co x Fe 3– x O 4 Epitaxial Films and Superlattices

Chemistry of Materials, 2013

ABSTRACT

Research paper thumbnail of Low-temperature electrodeposition of the high-temperature cubic polymorph of bismuth (III) oxide

Research paper thumbnail of Superconducting Filaments Formed During Nonvolatile Resistance Switching in Electrodeposited δ-Bi 2 O 3

ACS Nano, 2013

We show that electrodeposited films of δ-Bi2O3 in a Pt/δ-Bi2O3/Au cell exhibit unipolar resistanc... more We show that electrodeposited films of δ-Bi2O3 in a Pt/δ-Bi2O3/Au cell exhibit unipolar resistance switching. After being formed at a large electric field of 40 MV/m, the cell can be reversibly switched between a low resistance state (156 Ω) and a high resistance state (1.2 GΩ) by simply cycling between SET and RESET voltages of the same polarity. Because the high and low resistance states are persistent, the cell is a candidate for nonvolatile resistance random access memory (RRAM). A Bi nanofilament forms at the SET voltage, and it ruptures to form a 50 nm gap during the RESET step at a current density of 2 × 10(7) A/cm(2). The diameter of the Bi filament is a function of the compliance current, and can be tuned from 140 to 260 nm, but the current density in the RESET step is independent of the Bi diameter. An electromigration rupture mechanism is proposed. The Bi nanofilaments in the low resistance state are superconducting, with a Tc of 5.8 K and an Hc of 5 kOe. This is an unexpected result, because bulk Bi is not a superconductor.

Research paper thumbnail of Ternary Precursors for Depositing I-III-VI2 Thin Films for Solar Cells Via Spray CVD

The development of thin-film solar cells on flexible, lightweight, space-qualified substrates pro... more The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors (SSP's) can be used in either a hot or cold-wall spray chemical vapour deposition (CVD) reactor, for depositing CuInS 2 , CuGaS 2 and CuGaInS 2 at reduced temperatures (400 to 450 °C), which display good electrical and optical properties suitable for photovoltaic (PV) devices. X-ray diffraction studies, energy dispersive spectroscopy (EDS)

Research paper thumbnail of The Redox Chemistry of 4-Benzoyl- N- methylpyridinium Cations in Acetonitrile with and without Proton Donors:  The Role of Hydrogen Bonding

The Journal of Physical Chemistry B, 2001

In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated... more In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated (∆E 1/2 ∼ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence suggest that the positive shift of the second wave is due to hydrogen bonding between the two-electron reduced form of the ketone and the proton donors. While the one-electron reduction product is stable both in the presence and in the absence of the weak-acid proton donors, the two-electron reduction wave is reversible only in the time scale of cyclic voltammetry. Interestingly, at longer times, the hydrogen bonded adduct reacts further giving nonquaternized 4-benzoylpyridine and 4-(R-hydroxybenzyl)pyridine as the two main terminal products. In the presence of stronger acids, such as acetic acid, the second wave merges quickly with the first, producing an irreversible two-electron reduction wave. The only terminal product in this case is the quaternized 4-(Rhydroxybenzyl)-N-methylpyridinium cation. Experimental evidence points toward a common mechanism for the formation of the nonquaternized products in the presence of weaker acids and the quaternized product in the presence of CH 3 CO 2 H.

Research paper thumbnail of ChemInform Abstract: Electrodeposition of Co x Fe 3-x O 4 Epitaxial Films and Superlattices

ChemInform, 2013

ABSTRACT CoxFe3-xO4 (0 < x < 1) thin films are prepared by a one-step electrodeposi... more ABSTRACT CoxFe3-xO4 (0 < x < 1) thin films are prepared by a one-step electrodeposition from alkaline Fe3+- and Co2+-triethanolamine solutions.

Research paper thumbnail of The Redox Chemistry of 4-Benzoyl- N- methylpyridinium Cations in Acetonitrile with and without Proton Donors:  The Role of Hydrogen Bonding

The Journal of Physical Chemistry B, 2001

In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated... more In anhydrous CH 3 CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated (∆E 1/2 ∼ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence suggest that the positive shift of the second wave is due to hydrogen bonding between the two-electron reduced form of the ketone and the proton donors. While the one-electron reduction product is stable both in the presence and in the absence of the weak-acid proton donors, the two-electron reduction wave is reversible only in the time scale of cyclic voltammetry. Interestingly, at longer times, the hydrogen bonded adduct reacts further giving nonquaternized 4-benzoylpyridine and 4-(R-hydroxybenzyl)pyridine as the two main terminal products. In the presence of stronger acids, such as acetic acid, the second wave merges quickly with the first, producing an irreversible two-electron reduction wave. The only terminal product in this case is the quaternized 4-(Rhydroxybenzyl)-N-methylpyridinium cation. Experimental evidence points toward a common mechanism for the formation of the nonquaternized products in the presence of weaker acids and the quaternized product in the presence of CH 3 CO 2 H.

Research paper thumbnail of X-ray characterization of as-deposited, epitaxial films of Bi(012) on Au(111)

Surface Science, 2006

Electrodeposition is used to produce epitaxial single-crystal films on Au(1 1 1) substrates witho... more Electrodeposition is used to produce epitaxial single-crystal films on Au(1 1 1) substrates without annealing or other post-deposition modification. X-ray techniques show that the Bi(0 1 2) plane is parallel to the underlying Au(1 1 1) surface, and the azimuthal orientation of the films is determined. Combination of the X-ray data with in situ scanning tunneling microscopy (STM) images suggests a common growth mode from the first few layers up to thick films.

Research paper thumbnail of Epitaxial Electrodeposition of Prussian Blue Thin Films on Single-Crystal Au(110)

Journal of the American Chemical Society, 2003

Research paper thumbnail of The effects of high levels of vitamin E on the progression of atherosclerosis in the Watanabe heritable hyperlipidemic rabbit

The Journal of Nutritional Biochemistry, 1993

Watanabe rabbits (5-6 months of age) were divided into two groups (seven each). One group was fed... more Watanabe rabbits (5-6 months of age) were divided into two groups (seven each). One group was fed standard Purina Rabbit Chow and the second was fed the same diet supplemented with 2000 mg/kg diet vitamin E. (Purina Rabbit Chow contains about 30 rag vitamin E/kg diet). After 9 months, the rabbits were sacrificed and plasma lipids were determined, and the area of plaque involvement in the aortas was measured. The extent of plaque formation (percentage of the total surface covered with fatty streaks) was not significantly different in the two groups. However, there were differences observed in plasma lipids. Plasma total cholesterol, low density lipoprotein cholesterol, and triglyceride levels were 20-30% lower in the vitamin E-fed group. Also, the concentration of cholesterol in the lesions of the aortic arch was about25% lower in the vitamin E-fed group. These results indicate that high levels of vitamin E may have a beneficial effect on lowering plasma lipids observed in hyperlipidemia. (J. Nutr. Biochem. 4:651-654, 1993.)

Research paper thumbnail of Self-assembly and catalytic properties of 1,1′-bridged-2,2′-dipyridinium amphiphiles

Journal of Electroanalytical Chemistry, 1998

An electrochemical and computational study of a series of three 4-methyl-4%-nonadecyl-1,1%-bridge... more An electrochemical and computational study of a series of three 4-methyl-4%-nonadecyl-1,1%-bridged-2,2%-dipyridinium ions is reported. In 0.1 M KCl these ions self-assemble on glassy carbon to form a close-packed monomolecular layer. Incorporation of perchlorate into the film by counterion exchange results in enhanced film stability and limiting surface coverages of ca. 1.7 × 10 − 10 mol cm − 2 . As the 1,1%-bridge length is increased from two to four methylene groups, the reversible one-electron reduction potential of the dipyridinium head group decreases from − 499 to − 833 mV vs. AgAgCl0.1 M KCl. These relatively negative reduction potentials make adsorbed 1,1%-bridged-2,2%-dipyridinium amphiphiles powerful immobilized reductants in aqueous solution. The catalytic potency of these amphiphiles is demonstrated by catalyzing the reduction of ethyl 3-benzoyl acrylate and artemisinin.

Research paper thumbnail of Evidence that Monochloramine Disinfectant Could Lead to Elevated Pb Levels in Drinking Water

Environmental Science & Technology, 2006

Research paper thumbnail of Enantiospecific Electrodeposition of Chiral CuO Films from Copper(II) Complexes of Tartaric and Amino Acids on Single-Crystal Au(001)

Chemistry of Materials, 2004

... Surface Chirality of CuO Thin Films. Roland Widmer, Franz-Josef Haug, Pascal Ruffieux, Oliver... more ... Surface Chirality of CuO Thin Films. Roland Widmer, Franz-Josef Haug, Pascal Ruffieux, Oliver Gröning, Michael Bielmann, Pierangelo Gröning, and Roman Fasel. Journal of the American Chemical Society 2006 128 (43), 14103-14108. Surface Chirality of CuO Thin Films. ...

Research paper thumbnail of Epitaxial Electrodeposition of Zinc Oxide Nanopillars on Single-Crystal Gold

Chemistry of Materials, 2001

ZnO nanopillars have been electrodeposited epitaxially onto Au(111), Au(110) and Au(100) single-c... more ZnO nanopillars have been electrodeposited epitaxially onto Au(111), Au(110) and Au(100) single-crystal substrates. The nanopillars grow with the same [0001] out-of-plane orientation on all three substrates. The in-plane orientation was probed by X-ray pole figure analysis. ...

Research paper thumbnail of Epitaxial Electrodeposition of High-Aspect-Ratio Cu 2 O(110) Nanostructures on InP(111)

Chemistry of Materials, 2005

ABSTRACT

Research paper thumbnail of Epitaxial Electrodeposition of Copper(I) Oxide on Single-Crystal Gold(100)

Chemistry of Materials, 1999

... Application of current densities higher than about 0.1 mA/cm 2 in this solution gives rise to... more ... Application of current densities higher than about 0.1 mA/cm 2 in this solution gives rise to oscillations in the potential coincident with the deposition of a Cu/Cu 2 O layered nanostructure on the ... The effect of TiO2/Cu2O ... ... Electrochemical Deposition of Copper(I) Oxide Films. ...

Research paper thumbnail of Shape Control in Epitaxial Electrodeposition:  Cu 2 O Nanocubes on InP(001)

Chemistry of Materials, 2003

... 11) Hodes, G. Electrochemistry of Nanomaterials ... Electrochemical Deposition of Semiconduct... more ... 11) Hodes, G. Electrochemistry of Nanomaterials ... Electrochemical Deposition of Semiconductor Oxides on Reduced Graphene Oxide-Based Flexible, Transparent, and ... Synthesis, Shape Evolution, and Photocatalytic Activity of Truncated Cuprous Oxide Octahedron Microcrystals ...

Research paper thumbnail of Electrodeposition of Co x Fe 3– x O 4 Epitaxial Films and Superlattices

Chemistry of Materials, 2013

ABSTRACT

Research paper thumbnail of Low-temperature electrodeposition of the high-temperature cubic polymorph of bismuth (III) oxide

Research paper thumbnail of Superconducting Filaments Formed During Nonvolatile Resistance Switching in Electrodeposited δ-Bi 2 O 3

ACS Nano, 2013

We show that electrodeposited films of δ-Bi2O3 in a Pt/δ-Bi2O3/Au cell exhibit unipolar resistanc... more We show that electrodeposited films of δ-Bi2O3 in a Pt/δ-Bi2O3/Au cell exhibit unipolar resistance switching. After being formed at a large electric field of 40 MV/m, the cell can be reversibly switched between a low resistance state (156 Ω) and a high resistance state (1.2 GΩ) by simply cycling between SET and RESET voltages of the same polarity. Because the high and low resistance states are persistent, the cell is a candidate for nonvolatile resistance random access memory (RRAM). A Bi nanofilament forms at the SET voltage, and it ruptures to form a 50 nm gap during the RESET step at a current density of 2 × 10(7) A/cm(2). The diameter of the Bi filament is a function of the compliance current, and can be tuned from 140 to 260 nm, but the current density in the RESET step is independent of the Bi diameter. An electromigration rupture mechanism is proposed. The Bi nanofilaments in the low resistance state are superconducting, with a Tc of 5.8 K and an Hc of 5 kOe. This is an unexpected result, because bulk Bi is not a superconductor.

Research paper thumbnail of Ternary Precursors for Depositing I-III-VI2 Thin Films for Solar Cells Via Spray CVD

The development of thin-film solar cells on flexible, lightweight, space-qualified substrates pro... more The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors (SSP's) can be used in either a hot or cold-wall spray chemical vapour deposition (CVD) reactor, for depositing CuInS 2 , CuGaS 2 and CuGaInS 2 at reduced temperatures (400 to 450 °C), which display good electrical and optical properties suitable for photovoltaic (PV) devices. X-ray diffraction studies, energy dispersive spectroscopy (EDS)