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Chemistry - Bachelor's degree

Mostrando recursos 1 - 20 de 46

  1. The phase diagram of the sodium bromide-water system by the thermal analysis method

    Hebert, Richard Armand, 1929-
    by Richard Armand Hebert.

  2. Transition metal-facilitated C-C and C-F bond forming

    Perry, Ian B. (Ian Brooks)
    Chapter 1. Copper-Catalyzed Asymmetric Addition of Olefin-Derived Nucleophiles to Ketones A copper (I) catalyzed coupling olefins and ketones has been developed for the diastereo- and enantioselective generation of homopropargyl alcohols bearing vicinal stereocenters. This method allows for the generation of enantioenriched tertiary alcohols with a high degree of functional group compatibility. The utility of the process is further illustrated by a large scale synthesis with extremely low catalyst loading as well as the late stage modification of several pharmaceuticals. Chapter 2. Copper-Catalyzed Enantioselective Addition of Styrene-Derived Nucleophiles to Imines We describe the catalytic generation of amines bearing vicinal stereocenters with...

  3. Design of PolyMOCs and the synthesis of crosslinkers for the BASP platform

    Park, Jiwon Victoria
    In Chapter 1, two stepwise assembly strategies for the integration of metal-organic cages (MOCs) into polymers were explored. The first strategy creates Block Co-PolyMOCs (BCPMOCs), which feature the integration of MOCs into block copolymers (BCPs). In the first assembly step, BCPs functionalized with a bispyridyl ligand on the chain end undergo Pd induced MOC assembly. In the second step, microphase separation of BCPs is induced, introducing a physical cross-link between the star polymers and producing the desired BCPMOC networks in the bulk or gel state. In the second strategy, another orthogonal interaction is explored to create a different type of...

  4. Theoretical studies on the properties and dynamics of electronic excited states

    Hait, Diptarka
    Molecules are rarely found in electronic excited states under standard conditions but such states play a major role in chemical reactions. Computational prediction of properties of such states is hard with standard DFT protocols, as made evident by the failure of linear response TDDFT in predicting energies of charge-transfer excited states with semi-local functionals. Condensed phase dynamics of excited states are even more intractable on account of the computational cost scaling exponentially with the number of condensed phase particles under consideration. However, it is still possible to develop cheap but accurate approximations for properties and dynamics of excited states, and...

  5. Long-wavelength, reaction-based, fluorescent sensors for HNO and mobile zinc

    Wrobel, Alexandra T
    Chapter 1. Introduction A variety of inorganic molecules and ions participate in complex biological signaling networks. Three of these species are nitric oxide (NO), nitroxyl (HNO), and mobile zinc. Maintaining the homeostasis of these signaling molecules is vital and a deeper comprehension of their roles could help in understanding the pathology of specific diseases associated with their dysregulation. One method used to monitor levels of these analytes in biological samples is fluorescence microscopy. Shifting the fluorescence emission to longer wavelengths would improve these already existing probes. Having access to red and near-infrared (NIR) sensors is particularly useful for investigating the...

  6. Spectroscopic analysis and synthesis of nucleoside analogs for lethal mutagenesis

    Silvestre, Katherine J
    The high mutation rate of HIV makes treatment of HIV/AIDS difficult, as the virus can develop resistance to existing therapeutics. A novel antiviral nucleoside analog, 5-Aza-5,6-dihydro-2'- deoxycytidine (KP1212), employs the mechanism of lethal mutagenesis to avoid the problem of drug resistance and use the virus's high mutation rate against it. KP1212 is incorporated into DNA by HIV reverse transcriptase (RT) but mispairs with adenine instead of guanine, increasing the rate of purine transitions. This increased mutation rate can push HIV over its error catastrophe limit, resulting in viral ablation. To understand how KP1212 induces lethal mutagenesis, VT NMR studies were...

  7. The construction and use of a fluorine generator

    McGurty, James
    by James McGurty.

  8. Studies of metaphosphate acids and metaphosphate anhydrides in aprotic media

    Chakarawet, Khetpakorn
    The chemistry of metaphosphate acids has historically been studied in aqueous media, where acid-catalyzed hydrolysis and solvent leveling effects of these strong acids have prevented their observations and rigorous characterization. Solubilization of tri-, tetra-, and hexametaphosphates in aprotic media using the IPPN + cation ([PPNI+ bis(triphenylphosphine)imninium) has revealed the rich acid chemistry of metaphosphates that has previously been elusive in aqueous media. Protonation of imetaphosphates in organic media has resulted in six metaphosphate acids. X-ray diffraction studies display that the structural configurations of metaphosphate acids are dictated by strong hydrogen bonding interactions. As a consequence of anti-cooperative effect, intramolecular hydrogen...

  9. Understanding collagen-l folding and misfolding

    Taylor, Rebecca J. S.B. Massachusetts Institute of Technology
    Chapter One: Introduction to Type I Collagen and Osteogenesis Imperfecta Collagen-I is the primary proteinaceous component of skin, bone, and tendon. Disruptions in collagen-I homeostasis, typically due to non-synonymous mutations in collagen-- encoding genes, cause a variety of severe incurable diseases, including Osteogenesis Imperfecta (01). 01 phenotypes include brittle, deformed bones, frequent fractures, and growth deficiency. In order to fill the need for treatments that target the underlying causes of collagen-I-related diseases like 01, a better understanding of the collagen-I proteostasis network and how it differentially engages mutant and wild type collagen-1, is required. Chapter Two: Creation and Characterization of...

  10. A buffer gas cooled molecular beam apparatus for chirped pulse millimeter wave spectroscopy

    Klein, Ethan Avram
    An apparatus that utilizes buffer gas cooling to produce slow atomic (Ba, Ca) and molecular (BaF, CaF) beams is constructed. In-cell temperatures of 20 ± 0.25K are achieved with chamber cooldown times of under two hours. Laser Induced Fluorescence (LIF) spectra of BaF and CaF confirmed thermalization of the molecular beam to the temperature of the buffer gas and additional hydrodynamic cooling to rotational and translational temperatures under 10K. Laser fluence effects on the intensity of barium and calcium ablation were studied and used to optimize laser parameters for maximum ablation of the desired species. A chirped pulse millimeter wave...

  11. Spectroscopy and theory of cis-trans isomerization in the S₁ state of acetylene

    Changala, P. Bryan (Peter Bryan)
    This thesis consists of parallel experimental and theoretical studies of the rovibrational structure and dynamics of the Si state of acetylene, C2H2 . This small molecule is a prototypical system for the study of cis-trans isomerization, the barrier to which is moderately low in the Si state, presenting the opportunity to achieve a complete understanding of the global rovibrational dynamics of an isomerizing system. Our analysis of the spectra of ungerade vibrational levels in the region 45800-46550 cm-1 extends the complete assignment of trans vibrational levels to 4300 cm-1 above the Si electronic origin. These exhaustive assignments have enabled the...

  12. Targeted sensors for investigating mobile Zinc in biology

    Chyan, Wen, S.B. Massachusetts Institute of Technology
    Chapter 1. Sensing Strategies for Detection of Mobile Zinc. Mobile zinc plays important physiological roles in areas such as the hippocampus, prostate, and pancreas. A better understanding of the distribution of intracellular mobile zinc could provide insight into the pathology of diseases including prostate cancer and Alzheimer's disease, both of which have been linked to abnormal mobile zinc levels. Accordingly, a palette of spatially-specific mobile zinc sensors is needed to investigate mobile zinc in important areas such as the mitochondria or zinc vesicles in neurons. Instead of repeating the de novo sensor design process for each target, a modular approach...

  13. Some attempts to prepare triphenylcarbinyl p-toluenesulfonate, trityl tosylate

    Killheffer, John Vincent
    by John Vincent Killheffer, Jr.

  14. Progress towards the synthesis of tetracyclic heteroaromatic compounds via tandem benzannulation-cyclization strategies

    Mamaliga, Galina
    A tandem benzannulation-cyclization strategy was successfully applied to the synthesis of a tetracyclic heteroaromatic compound expected to have interesting electronic properties. Benzannulation of a diazo ketone and a ynamide yielded a highly substituted aniline that was cyclized to indole according to protocols developed in our laboratory previously.

  15. Physical and biological properties of a Pt(ll) complex of a beta-diketiminate ligand with pendant quinoline arms

    Hope, Jennifer M
    A monoanionic, tetradentate [beta]-diketiminate (BDI) ligand with pendant quinoline arms, BDIQQH was coordinated to Pt(II) to yield the square-planar complex [Pt(BDIQQ)]CI. This complex was characterized by NMR spectroscopy, ESI-MS, FTIR spectroscopy, UVVisible absorbance spectroscopy, and cyclic voltammetry. Computational studies, including geometry optimizations and frequency calculations, were carried out to further analyze the electronic structures of the complexes. In addition, the DNA-binding properties of the complexes were evaluated by UV-Vis titrations and an ethidium-bromide displacement assay. Our results indicate that the compounds interact with DNA, although the mode of interaction is still ambiguous. Fluorescence studies were also performed to investigate the...

  16. Palladium-catalyzed C-N cross-coupling reactions toward the synthesis of drug-like molecules

    McAvoy, Camille Z
    The development of methodologies for C-N bond formation reactions is an important scientific challenge because of many academic and industrial applications. This work will focus particularly on palladium-catalyzed cross-couplings of amine-containing compounds with aryl halides. The scope of the BrettPhos precatalyst for the cross-coupling of ortho-substituted aryl iodides with amides is studied using substrates with a variety of functional groups. Due to potential metal-chelating issues with some of the substrates used in this study, a proposed ligand synthesis is discussed in which one of the methoxy groups of BrettPhos is replaced with a morpholine capable of occupying palladium's open coordination...

  17. Nitrogen in sewage

    Allen, Charles R
    by Charles R. Allen.

  18. Some experiments on the influence of salts on the solubility of other salts

    Gage, Stehen DeMeritte
    by Stephen DeMeritte Gage.

  19. A study of the sanitation of a swimming pool

    Lane, Gerould T
    by Gerould T. Lane.

  20. Investigation of uranium oxide of low oxidation state

    Nelson, Carl W
    by Carl W. Nelson.

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