Small molecule organic materials based on perylene- and naphthalene- diimide are synthesized and characterized for use as semiconductor thin films in organic field-effect transistors. The orbital energetics of the materials are investigated via electrochemical, spectroscopic, and computational techniques. The thin film solids are characterized by x-ray diffraction techniques and surface...
Direct dynamics quasiclassical trajectory (QCT) calculations are performed to study the dynamics of model atom + polyatom reactions. In the first part of this thesis, we examine adiabatic dynamics of H/O reaction with simple alkanes, CD4 and C2H6. Overall good agreement with state-of-the-art experiments shows that the molecular motion is...
Alkenylsilanes of varying chain lengths are investigated as simultaneous chain transfer agents + comonomers in organotitanium-mediated olefin polymerization processes. Ethylene + alkenylsilane polymerizations were carried out with activated Me2Si(Me4C5)(NtBu)TiMe2 and (-CH2CH2-3,3'){(5-indenyl )[1-Me2Si(tBuN)]}2Ti2Me4 precatalysts. Alkenylsilane incorporation levels follow the trend C8H15SiH3 < C6H11SiH3 ≈ C4H7SiH3 < C3H5SiH3. Long-chain branching levels versus...
Theoretical studies on electronic structure governing charge transport properties are investigated to understand and improve the prediction of electron charge carrier organic semiconductors used in field-effect transistors. Perfluorinated oligothiophene semiconductors have shown experimental n-type behavior, but placement of fluorinated aryl groups changes charge polarities. Models were developed to investigate how...
This thesis consists of the synthesis and photophysical characterization of chlorophyll- and porphyrin- based multichromophore arrays designed for the purpose of studying energy and charge transfer therein. The first series of arrays consists of donor-acceptor dyads in which various arylene diimide electron acceptors are attached through a phenyl group to...
A catalytic, multi-component coupling reaction for the synthesis of nitrogen-containing heterocycles has been developed, via the reaction of an imine, &#945;-diazoester and unsaturated coupling partner in the presence of a copper(I) or rhodium(II) transition metal catalyst with excellent diastereo-selectivities and high yields. The transition metal-catalyzed decomposition of a diazo compound...
Two new strategies have been developed to accomplish direct nucleophilic acylation reactions. In the first approach, acylsilanes are added to various electrophiles using N-heterocyclic carbenes as catalysts. The second method utilizes O-silyl thiazolium carbinols as stoichiometric acyl anion precursors to afford acylated products under mild reaction conditions.
N-heterocyclic carbenes generated...
Local structure determination in amorphous and disordered systems, which are crystallographically intractable, is critical for gaining an understanding of their properties. X-ray absorption spectroscopy (XAS) is an excellent tool for local structure determination in amorphous and disordered environmental materials. Amorphous manganese oxides produced by the freshwater bacterium Leptothrix discophora SP6...
Counteranion effects on the rate and stereochemistry of propylene polymerization mediated by ion-pair complexes derived from dimethylzirconocene precatalysts activated with strongly Lewis-acidic perfluoroarylmetalloid cocatalyst/activators are shown to arise from the strength of the cation-anion interaction. This is quantified using CS-symmetric Me2C(Cp)(Flu)ZrMe2 (Cp = C5H4, &#951;5 cyclopentadienyl; Flu = C13H8, &#951;5...
In Chapter 1, a series of "constrained geometry" organoactinide complexes, (CGC)An(NMe)2 (CGC = Me2Si(h5-Me4C5)(tBuN); An = Th, 1; U, 2), prepared via efficient in situ, two-step protodeamination routes in good yields and high purity, is presented. Both 1 and 2 are quantitatively converted to the neutrally charged, solvent-free dihalides (1-Cl2,...