Chemistry Commons^™

Prospects Of D-Π-A Structured Porphyrins And Their Photoelectrochemical Application, Shuang-Shuang Liu, Jian-Feng Lu, Ming-Kui Wang

Journal of Electrochemistry

Porphyrins and their metalloderivatives are a class of compounds exhibiting a wide variety of interesting and highly useful properties, such as chlorophyll. Porphyrins are particularly interesting in photoelectrochemical applications due to their structural similarity to chlorophylls in natural photosynthetic systems, as well as their strong and tunable absorption properties. Recently, various porphyrins have been extensively studied for their applications in solar cells, photocatalytic hydrogen production, optical information storage and others. This review will focus on the unique physical and chemical properties of D-π-A structured porphyrins, and their photovoltaic performances in dye-sensitized solar cells. A brief discussion in the future development …

Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging …

Synthesis And Characterization Of "Click Inspired" Thiol-Ene-Fullerene Nanocomposites, Amber Danielle Windham

Dissertations

This work explores the covalent incorporation of C₆₀ and Sc₃N@C₈₀ fullerenes into thiol-ene networks by a facile, one-pot photochemical reaction with multifunctional thiol and alkene monomers. Synthesis of disulfide bonds within the tri-functional thiol monomer served to photochemically initiate the reaction when cleaved. This was followed by thermal curing of the pre-polymer for preparation of fullerene-containing thiol-ene films. Films were characterized by standard techniques including infrared spectroscopy, gel percent, and thermogravimetric analysis. The role of C₆₀ and Sc₃N@C₈₀ as suitable alkenes for free-radical reaction with multifunctional thiols was investigated by preparing a …

Understanding The Optical Properties Of Ambient Sub-And Supermicron Particulate Matter: Results From The Cares 2010 Field Study In Northern California, Christopher D. Cappa, Katheryn R. Kolesar, Xiaolu Zhang, Dean B. Atkinson, Mikhail S. Pekour, Rahul A. Zaveri, Alla Zelenyuk, Qi Zhang

Chemistry Faculty Publications and Presentations

Measurements of the optical properties (absorption, scattering and extinction) of PM1, PM2.5 and PM10 made at two sites around Sacramento, CA, during the June 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are reported. These observations are used to establish relationships between various intensive optical properties and to derive information about the dependence of the optical properties on photochemical aging and sources. Supermicron particles contributed substantially to the total light scattering at both sites, about 50 % on average. A strong, linear relationship is observed between the scattering Ångström exponent for PM10 and the fraction of the scattering that is …

The Marine Cyanate Cycle, Brittany Widner

OES Theses and Dissertations

Cyanate (OCN-) is a reduced nitrogen compound with the potential to serve as a nitrogen and carbon source for marine microbes. Evidence from genomes and culture studies indicated that several marine cyanobacterial groups, including representatives of the globally important genera Synechococcus and Prochlorococcus, might be capable of cyanate assimilation. However, prior to this study, the distribution, bioavailability, and production pathways of cyanate were unknown in natural systems due to the absence of a sensitive cyanate assay; and the ability of organisms to assimilate cyanate on relevant timescales was unknown because we lacked a suitable tracer for measuring uptake. I developed …

Efficient Bimolecular Mechanism Of Photochemical Hydrogen Production Using Halogenated Boron-Dipyrromethene (Bodipy) Dyes And A Bis(Dimethylglyoxime) Cobalt(Iii) Complex, Randy Pat Sabatini, Brian M. Lindley, Theresa M. Mccormick, Theodore Lazarides, William Brennessel, David W. Mccamant, Richard Eisenberg

Chemistry Faculty Publications and Presentations

A series of Boron-­dipyrromethene (Bodipy) dyes were used as photosensitizers for photochemical hydrogen production in conjunction with [Co^III(dmgH)2pyCl] (where dmgH = dimethylglyoximate, py = pyridine) as the catalyst and triethanolamine (TEOA) as the sacrificial electron donor. The Bodipy dyes are fully characterized by electrochemistry, x-­‐ray crystallography, quantum chemistry calculations, femtosecond transient absorption and time-­‐resolved fluorescence, as well as in long-­‐term hydrogen production assays. Consistent with other recent reports, only systems containing halogenated chromophores were active for hydrogen production, as the long-­‐lived triplet state is necessary for efficient bimolecular electron transfer. Here, it is shown that the photostability of …

Photoassisted Generation Of Complex N, O, S Polyheterocycles, Weston James Umstead

Electronic Theses and Dissertations

This research set out to continue the exploration and diversification of excited state o-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.

Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.

Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to …

Studies On Hydroxyl Radical Formation And Correlated Photoflocculation Process Using Degraded Wood Leachate As A Cdom Source, Luni Sun, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

In this study, we examined hydroxyl radical (•OH) formation with respect to photoreactivity of colored dissolved organic matter (CDOM), the Fenton reaction, and photoflocculation using leachate from decaying wood. The relationship between •OH photoproduction rate and leachate optical properties (UV-visible absorption and fluorescence excitation-emission matrices (EEMS)) was studied during irradiation using a UV solar simulator. The results showed that the •OH photochemical formation rate is strongly related to humic-like fluorescence as characterized by parallel factor analysis (PARAFAC), and that these fluorescence components are more photolabile than most of the other CDOM components. Fourier transform infrared spectroscopy (FT-IR) indicated the photodegradation …