Chemistry Commons^™

Carbon-Carbon Bond Formation Via O-Lithiointermediates, Julia Raymer

Masters Theses & Specialist Projects

The process of C-C bond formation via Directed ort/zo-Metalation (DoM) consists of two separate steps. Utilizing fractional equivalents of TMEDA in hydrocarbon solvents at 60°C, o-lithiation of anisole and dimethylaniline can be effected in >95% yields. The first step in the DoM process involves preparation of solid samples of these o-lithiointermediates. Completing the sequence, the second step concerns formation of a new arene-derivative bond at the reactive site. For this thesis the arene-derivative bond formed is to carbon. Various carbon electrophiles have been studied using different solvent systems, and results reveal a possible disconnect between the reaction conditions for the …

Spectroscopic Studies Of Chlorophyll A Complexes With Trinitro-Substituted Flourene Derivatives, Stephanie Smalley

Masters Theses & Specialist Projects

Absorption, fluorescence, and excited-state lifetime studies of chlorophyll a (Chl a) with fluorene, 2-(2,4,7-Trinitro-fluoren-9-ylideneaminooxy)-propionic acid (TFPR), 2- (2,4,7-Trinitro-fluoren-9-ylidenemethyl)-phenol, (TFPH), and 9-Isopropylidene-2,4,7- trinitro-9H-fluorene (ITNF) have been investigated. These systems were studied in acetonitrile and dichloromethane at room temperature. Absorption data were analyzed with the Nash plot. Linearity of the Nash plots proved that a 1:1 complex was formed between the donor and acceptor. Ground state binding constants (Ka) of each system were also determined from the y-intercept of these plots. Fluorescence data were analyzed with a Stern-Volmer plot. The quenching constants (Ksv) were obtained from the slope of these plots. These …

Cesium Effect: A Mild And Efficient Synthesis Of Secondary And Tertiary Phosphines, Matthew Honaker

Masters Theses & Specialist Projects

A mild and efficient method to synthesize a variety of secondary and tertiary, as well as disecondary and ditertiary phosphines has been developed. Using reaction conditions that include cesium hydroxide, molecular sieves, and DMF, at room temperature, a wide range of alkyl halides has been coupled to primary or secondary phosphines to yield secondary or tertiary phosphines. Included were activated and aliphatic halides, as well as base sensitive functional groups. In addition, examples of disecondary and ditertiary ligands have also been prepared using similar reaction conditions. The synthesis of a P-N-P ligand was also accomplished with these procedures. Optically active …

Directed Ortho Metalation In Hydrocarbon Solvents: Opposing Pi-Resonance Effects, Barry Woosley

Masters Theses & Specialist Projects

Hydrocarbon solvents are known to be unreactive toward organolithium reagents and do not typically support ortho-metalation reactions without the aid of a promoter. An exception would be an arene substrate having the capability to bidentate complex to the reactive alkyllithium dimer, which enables ortho-metalation to occur in high yields. A second, more limiting exception, would be that the arene substrate possesses localized lone pairs of electrons, as is the case when the directed ortho metalating group (DMG) is located in the benzyl position. The work reported here centers upon developing a third and larger class of arene substrates that are …

Determination Of Carbon Nanotube Modification By Tg-Ms And Pyrolysis-Gc/Ms, Quentin Lineberry

Masters Theses & Specialist Projects

Uniform dispersion of carbon nanotubes (CNTs) has been one of the major impediments to the full development of the incredible suite of properties offered by CNTs, specifically single-walled carbon nanotubes (SWNTs). However, investigators at NASA Langley and the National Institute of Aerospace Research have recently obtained (SWNTs) that are soluble in select solvents, including THF, DM Ac, and ODCB. The SWNTs were exposed to reagents used in cited fullerene modification chemistry in an attempt to produce soluble SWNTs. Upon further examination, it was determined that the intended functionalization had not occurred, and some other phenomenon was responsible for the SWNTs …

Development Of A Gene Transfer System In Clostridium Scindens Vpi 12708, Rashmi Ramasubbaiah

Masters Theses & Specialist Projects

Clostridium scindens VPI 12708 (previously known as Eubacterium sp. VPI 12708) is a bile-acid dehydroxylating bacterium originally isolated from the feces of a colon cancer patient. Many genes required for bile acid 7-a dehydroxylation are found on a large bile acid inducible operon (bai) that has been extensively studied. However the bai promoter, which directs expression of the bai operon, has yet to be characterized due, in part, to a lack of a functional genetic transfer system for this strain. A spontaneous rifampinresistant Clostridium scindens VPI 12708 mutant was used as a recipient to determine the efficacy of conjugation as …

Development Of An Analytical Method For Distinguishing Ammonium Bicarbonate From The Products Of An Aqueous Ammonia Co2 Scrubber And The Characterization Of Ammonium Bicarbonate, Lingyu Meng

Masters Theses & Specialist Projects

The link between anthropogenic emissions of CO2 with increased atmospheric CO2 levels and, in turn, with increased global temperature has been well established and accepted. Using aqueous ammonia to capture CO2 and produce an inexpensive nitrogen fertilizer, ammonium bicarbonate (ABC) has been thought as a feasible approach to CO2 sequestration.

Due to the different concentrations of reactants and reaction conditions, different carbon-ammonium composites can be produced. In view of achieving a maximum of NH3 utilization in the capture of CO2, the product of ABC will be ideal. Hence the ABC in the products needs to be identified. Various analytical techniques …