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Thesis (Ph. D.)--Conservatory of Music and School of Education. University of Missouri--Kansas City, 2006. / "A dissertation in music education and curriculum and instruction." Advisor: Charles R. Robinson. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Dec. 20, 2007. Includes bibliographical references (leaves 167-179). Online version of the print edition.

Radicals are potential building blocks to prepare conductive and magnetic materials. In order to achieve high conductivity, materials displaying a large bandwidth W and a low on-site Coulomb repulsion energy U must be generated. Semiquinone-bridged bis-1,2,3-dithiazolyl radicals (R = Cl, Ph, Me and the MeCN adduct of R = Cl) represent a new family of resonance stabilized neutral radical for use in the design of single-component conductive materials were prepared and fully characterized. In solid state these radicals remain as unassociated (monomers) in the solid state and typically form superimposed alternating π-stacks or slipped π-stacks, arranged in several different space groups. The predominate intermolecular interactions are S•••N′ and / or S•••O′ contacts, which increase the dimensionality from one dimensional π-stacked systems (i.e., poor lateral overlap) to two dimensional systems in the solid state. Thus the semiquinone-bridged bis-dithiazolyl radicals exhibit a significant decrease in activation energy (ca. 0.1 – 0.2 eV) and the conductivity is two to three orders of magnitude (ca. σ ≈ 1E-5 – 1E-2 S / cm) higher in comparison to the previously reported pyridine based systems. This high conductivity is attributed to the low on-site Coulomb repulsion energies (U) which were estimated from the solution cell potentials (EPC) obtained from CV measurements and improved bandwidth (W) from the S•••N′ and / or S•••O′ interactions. Furthermore, the all sulphur containing semiquinone-bridged bis-dithiazolyls have the lowest activation energies and the highest conductivity under ambient conditions compared with other all sulfur nitrogen based radicals known to date. The semiquinone-bridged bis-dithiazolyl (R = Cl) orderes as spin-canted antiferromagnets, TN = 8 K, and displayed large coercivity (80 Oe). The ZFC-FC measurement at low field (i.e., H = 100 Oe) established the phase transition temperatures and the spontaneous magnetization was used to estimate the spin canting angles (~ 0.14°). In the case of R = Ph, the antiparallel alignment of the ferromagnetic coupled chains leads to a spin-canted antiferromagnet (TN = 4.5 K), which undergo a unique field induced spin flop transition. The MeCN solvated of R = Cl behaves as a simple paramagnet at room temperature with bulk antiferromagnetic interactions, but no observed magnetic ordering from 2-300 K.

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 191-203).

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1,2,4,6-thiatriazine radicals can be neutral radical conductors in the context of molecular metal design. After initial investigations they were ignored in favor of other prospective ring systems. A more general route to 1,2,6-thiatriazine radicals herein is reported. Two crystal structures were obtained for the radicals 5-phenyl-3-trichloromethyl-1,2,4,6-thiatriazine 7c and 5-phenyl-3-trifluoromethyl-1,2,4,6-thiatriazine 8c. 7c displays a unique head-to-tail packing arrangement not seen in previous thiatriazine structures. Two crystal structures of the precursor phenyl/trichloro imidoylamidine 1c and phenyl/trifluoromethyl imidoylamidine 2c show strong intramolecular hydrogen bonding and relatively weak intermolecular hydrogen bonding. EPR of the radicals are highly diagnostic and display coupling to three unique nitrogen atoms, of which a small but very distinct influence on the hyperfine coupling constants from the remote aryl-substituents is seen. Solution electrochemistry assessed the redox tunability of the radicals to these substituents. DFT calculations of the hyperfine coupling constants and oxidation and reduction potentials corroborated well with experimental data. / xv, 176 leaves : ill. ; 28 cm.

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