http://hdl.handle.net/1721.1/7792 2013-05-16T22:57:51Z http://hdl.handle.net/1721.1/78532 Theoretical investigation of Stokes shifts and reaction pathways Top, Laken M. (Laken Michelle) Solar thermal fuels and fluorescent solar concentrators provide two ways in which the energy from the sun can be harnessed and stored. While much progress has been made in recent years, there is still much more to learn about the way that these applications work and more efficient materials are needed to make this a feasible source of renewable energy. Theoretical chemistry is a powerful tool which can provide insight into the processes involved and the properties of materials, allowing us to predict substances that might improve the efficiency of these devices. In this work, we explore how the delta self-consistent field method performs for the calculation of Stokes shifts for conjugated dyes. We also develop a new reaction path finding method which uses a combination of trigonometric functions and information about the initial and final states in the reaction to generate an approximate path. We show that this path finding method works well for several model systems including a seven atom Lennard-Jones cluster. The ability to calculate excited state properties at a reasonably low cost and to find convergent reaction pathways is extremely beneficial for understanding and improving solar devices. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 38-40). 2012-01-01T05:00:00Z http://hdl.handle.net/1721.1/78531 Ring-opening metathesis polymerization of 3-substituted cyclooctenes initiated by group 6 alkylidene complexes Kozera, Daniel James The highly cis,head-to-tail (cis,HT) selective ring-opening metathesis polymerization of 3-substituted cyclooctenes (3-RCOE; R = methyl, hexyl, phenyl) initiated by high oxidation state M and W alkylidene complexes is described herein. W(NtBu)(CHCMe₃)(pyr)(OHMT) combined high cis,HT selectivity (>98% cis,HT) with high activity, achieving 76% conversion of 5000 equivalents of 3-HexCOE after 24 h at room temperature. The resulting cis,HT-poly(3-RCOE)s (R = Me, Hex) were isolated, characterized by ¹H and ¹³C NMR, size-exclusion chromatography, and differential scanning calorimetry, and hydrogenated to generate the corresponding saturated polymer. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references. 2012-01-01T05:00:00Z http://hdl.handle.net/1721.1/78512 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. Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Chemistry, February 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references. 2012-01-01T05:00:00Z http://hdl.handle.net/1721.1/78439 Comparison of phenanthriplatin, a novel monofunctional platinum based anticancer drug candidate, with cisplatin, a classic bifunctional anticancer drug Li, Meiyi, S.M. Massachusetts Institute of Technology Nucleotide excision repair, a DNA repair mechanism, is the major repair pathway responsible for removal of platinum-based anticancer drugs. In this study, 146 bp duplexes were prepared containing either a site-specific cisdiammineplatinum( Il)-DNA intrastrand d(GpG) cross-link or a cisdiamminephenanthridinechloroplatinum( Il)-DNA dG adduct. Comparison of the repair efficiencies of the two adducts reveals that the diamminephenanthridinechloroplatinum(lI)-DNA dG lesion eludes the nucleotide excision repair pathway better than diammineplatinum(lI)-DNA intrastrand d(GpG) cross-link. A factor that may be relevant to the difference is the influence of platination on DNA-mediated charge transfer. Atomic force microscopy is a method by which we can explore the possibility that phenanthriplatin influences charge transfer properties of DNA. Long DNA duplexes site-specifically modified with cisplatin or phenthanriplatin were prepared for AFM studies. Thesis (S.M. in Inorganic chemistry)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.; Cataloged from PDF version of thesis. Vita.; Includes bibliographical references (p. 38-40). 2012-01-01T05:00:00Z