Physical Sciences and Mathematics Commons^™

The Generality Of The Guga Mrci Approach In Columbus For Treating Complex Quantum Chemistry, Hans Lischka, Ron Shepard, Thomas Müller, Peter G. Szalay, Russell M. Pitzer, Adelia J. A. Aquino, Carol A. Parish, Et Al.

Chemistry Faculty Publications

The core part of the program system COLUMBUS allows highly efficient calculations using variational multireference (MR) methods in the framework of configuration interaction with single and double excitations (MR-CISD) and averaged quadratic coupled-cluster calcu- lations (MR-AQCC), based on uncontracted sets of configurations and the graphical unitary group approach (GUGA). The availability of analytic MR-CISD and MR-AQCC energy gradients and analytic nonadiabatic couplings for MR-CISD enables exciting applications including, e.g., investigations of π-conjugated biradicaloid compounds, calculations of multitudes of excited states, development of dia- batization procedures, and furnishing the electronic structure information for on-the-fly surface nonadiabatic dynamics. With fully vari- ational …

Aromatic Ouroboroi: Heterocycles Involving A Sigma-Donor-Acceptor Bond And 4n+2 Pi-Electrons, Kelling J. Donald, William Tiznado, Rodrigo Baez-Grez, Diego Inostroza

Chemistry Faculty Publications

The aromaticity and dynamics of a set of recently proposed neutral 5- and 6-membered heterocycles that are closed by dative (donor–acceptor) or multi-center s bonds, and have resonance forms with a Hu¨ckel number of p-electrons, are examined. The donors and acceptors in the rings include N, O, and F, and B, Be, and Mg, respectively. The planar geometry of the rings, coupled with evidence from different measures of aromaticity, namely the NICSzz, and NICSpzz components of the conventional nucleus independent chemical shifts (NICS), and ring current strengths (RCS), indicate non-trivial degrees of aromaticity in certain cases, including the cyclic C3B2OH6 …

One-Pot Silyl Ketene Imine Formation-Nucleophilic Addition Reactions Of Acetonitrile With Acetals And Nitrones, C. Wade Downey, Grace Ann L. Robertson, Jhonmattew Santa, Kari R. Flicker, William M. Stith

Chemistry Faculty Publications

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote the conversion of acetonitrile to its silyl ketene imine in situ when acetonitrile is employed as solvent. Residual TMSOTf acts as a Lewis acid catalyst to activate acetals and nitrones in the reaction mixture, yielding β-methoxynitriles and β-(silyloxy)aminonitriles, respectively. Some reaction products undergo elimination under the reaction conditions to provide the α,β-unsaturated nitrile directly.

Aldol Condensations And Nitrile Aldol Reactions Mediated By Trimethylsilyl Trifluoromethanesulfonate, Samuel R. Bottum

Honors Theses

In the presence of excess trimethylsilyl trifluoromethanesulfonate (TMSOTf), ketones and esters undergo aldol addition and dehydration to yield chalcones and cinnamates. This one-pot reaction proceeds through in situ enol silane formation, avoiding the need to pre-form and purify the nucleophile in the Mukaiyama aldol reaction. The stoichiometry of the TMSOTf controls whether the reaction proceeds with simple addition or addition-dehydration. When (trimethylsilyl) acetonitrile is stirred with an aldehyde and TMSOTf, nitrile aldol addition is observed.

Synthesis, Characterization, And Reactivity Of Palladium Proazaphosphatrane Complexes, Adrian D. Matthews

Honors Theses

Palladium-catalyzed cross-coupling reactions provide an efficient pathway to a wide variety of otherwise inaccessible compounds. In this study, the synthesis and reactivity of novel palladium proazaphosphatrane complexes that are believed to be intermediates in C–N cross-coupling reactions are described. Both the fundamental reactivity of these complexes and elementary steps involved in a catalytic process are demonstrated. The catalytic viability of palladium proazaphosphatrane complexes is shown through stoichiometric and catalytic cross-coupling reactions. Our findings support the long-standing hypothesis that proazaphosphatranes are conformationally flexible ligands that stabilize a number of catalytic intermediates.

Design Of New Ruthenium Complexes For Photoactivated Chemotherapy, Lindsey Paul

Honors Theses

Photoactivated chemotherapy (PACT) offers a targeted approach to cancer treatment through selective drug activation. Substitutionally labile ruthenium-based prodrugs undergo ligand-loss when irradiated, producing an unbound ligand and a Ru-aqua complex. We report the synthesis and cytotoxicity of several new ruthenium-centered complexes and their irradiation products for use in PACT. A series of complexes were synthesized in order to study the effects of structural differences on cell viability. Cell viability was tested on T47D human breast cancer cells in the presence of compound to determine cytotoxicity and dose-response. While neither the Rucomplexes nor their ligands demonstrated cytotoxicity, their Ru-aqua dissociation complexes …

Nanoparticles As Alternative Ceramic Glaze Colorants, Nathan Dinh

Honors Theses

Metallic nanoparticles, including gold and silver, have been used in wide-ranging applications due to their versatile characteristics. These include catalysis, biosensing, imaging, cancer treatments, and art. Due to the phenomenon called surface plasmon resonance, metallic particles change optical properties when sized in the nanoscale based on their composition, shape, diameters, or aspect ratios. In study, these robust nanoparticle systems are applied as an alternative to traditional bulk metal colorants in ceramic glazes.

In this study, the research goals are two-fold: to understand firing mechanism on the gold nanoparticle size and to develop these processes for wider use by regular artisans. …