| A penta-substituted benzene was synthesized to serve as the polymer precursor for a proposed helicene. Starting from 2-nitro- m-xylene, synthesis of 11 highly-substituted benzenes is reported. In particular, 1,5-dibromo-2,4-diethenyl-3-nitrobenzene was produced by two methods: from a double Wittig reaction of 1,5-dibromo-2,4-bis(bromomethyl)-3-nitrobenzene, and from the double elimination product of 2,2'-(4,6-dibromo-2-nitrobenznene-1,3-diyl)diethanol. Subsequent reactions yielded either 3,5-dibromo-2,6-divinylaniline by reduction, or the polymer precursor 2-(5-bromo-2,4-diethenyl-3-nitrophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane upon borylation. An alternative synthetic strategy involving a protected aniline produced N-acetyl-N-[3,5-dibromo-2,6-bis(bromomethyl)phenyl]acetamide. A tetra-substituted dihydrobenzofuran, 2-(4,6-dibromo-2-phenyl-2,3-dihydro-benzofuran-7-yl)-1-phenylethanol, was serendipitously synthesized and isolated as a mixture of diastereomers. The reaction involves an unusual ipso aromatic substitution to displace a nitro group.;The structure and dynamic properties of the highly-strained polycyclic aromatic hydrocarbon 18,18'-dihexyl[9,9']biphenanthro[9,10-b]triphenylene were computed using electronic structure methods. Homodesmotic calculations were used to explore the amount of strain vested in the central gulf-gulf bond. The homolytic bond dissociation energy was found to be ∼55% that of biphenyl. Density functional theory calculations assisted in the assignment of 1H and 13C NMR resonances. Another computational investigation, which was supported by variable temperature NMR data, revealed a barrier to inversion for the helical twist of the two phenanthro[9,10- b]triphenylene moieties.;Two projects dealt with the dynamic simulation of gold core nanoparticles with thiol ligands. The first project addressed phase segregation of octanethiol and mercaptopropionic acid ligands on the surface of nanoparticles. A continuum model, which offers the advantage of simulating the mobility of ligands on the core surface of a nanoparticle, was adapted for application with molecular dynamics. Striped patterns on the surface of particular mixed monolayer nanoparticles are the result of phase separation between the hydrophobic and hydrophilic ligands. These rippled patterns are most likely to exist when the ligand ratio is 1:1.;The second project addressed the inhibition of alpha-chymotrypsin activity by a mercaptoundecanoic acid covered nanoparticle. Simulations supported the hypothesis that the ligands' anionic headgroups interact with the enzyme's cationic residues, and block access to the active site. The simulations also suggest that distortion of the active site geometry may also inhibit enzyme activity. |
