Significant effort has centered on improving methods for producing single-walled carbon nanotubes (SWCNTs) in large quantities because of their unique electrical, mechanical, and thermal characteristics. Most production methods yield many diverse SWCNT structures, which are defined by the imaginary rolling up of a graphene sheet. The discovery of intrinsic band-gap fluorescence from semiconducting SWCNTs suspended in surfactant solutions and the subsequent assignment of the various excitation-emission features for specific SWCNT structures has opened the door to a broad range of experimental endeavors previously unavailable. This thesis describes recent progress in developing fluorimetric analysis methods and applying them to chemical problems. First, a unique turn-key SWCNT fluorescence analyzer was built and novel data analysis method was implemented for the bulk characterization of carbon nanotube samples. The instrument and analysis are illustrated by comparing deduced diameter and chirality distributions for a typical SWCNT suspension against those obtained from a general purpose spectrofluorometer system. Secondly, the use of rationally designed peptide sequences as biocompatible solubilizing agents for SWCNTs is demonstrated. This study illustrates how these peptides can be tailored to either shift the average diameter of bulk suspended SWCNTs or improve sustainable nanotube solubilization through the use of peptide crosslinking. Finally, a project is described in which the addition of diazonium salts to SWCNT suspensions quenches the intrinsic near-infrared fluorescence of the semiconducting SWCNTs through sidewall chemical reactions. Structure dependent reactivities of SWCNT species were observed in bulk measurements and variations of diazonium salt, suspending agent, and/or pH were used to moderate the reactivity trends.

The physicochemical and engineering performance properties of several API class G and H ordinary Portland cements (OPCs) from various foreign and domestic sources have been investigated. The engineering performance properties are found to vary from sample to sample, and sources for this variation were sought out and identified. Magic angle spinning (MAS) 29Si nuclear magnetic resonance (NMR) experiments were marked by unusual relaxation behavior due to paramagnetism inherent in OPCs. A model system was created to mimic the paramagnetism of the cements and the system's relaxation behavior was analyzed. The iron in the calcium aluminoferrite (C4AF) provides the paramagnetism sufficient to substantially increase the relaxation rates of the 29Si in the tricalcium silicate (C3S) and dicalcium silicate (C2S) of cement. Several relaxation techniques were evaluated for analyzing cement relaxation, and saturation recovery was identified as the preferred technique. Correlations of data from the saturation recovery experiments with engineering performance properties, especially the strength development of cement pastes, were obtained facilely. An error analysis of the NMR and engineering performance testing techniques was conducted, which indicated that NMR measurements produced less error than the engineering performance tests. A best practice, modified from the saturation recovery experiment, is proposed for use in property correlations. Additionally, 13C MAS NMR was used to characterize various fluorinated single-walled carbon nanotubes (F-SWNTs), which proved surprisingly effective in attenuating 13C-19F dipolar interactions and quantifying the extent of functionalization present at high degrees of reaction. The mixed-metal nanocluster known as FeMoC was also characterized by MAS NMR. The impact of the paramagnetic Fe3+ in the Keplerate cage on the 31P nuclei in the caged Keggin ion of FeMoC was evident in the greatly reduced relaxation times measured.

The limitations of zero quantum NMR pulse sequences reported in the literature are discussed. Several new pulse sequences which improve and extend the scope of the currently available pulse sequences are described. A modified double quantum filtered proton zero quantum 2D-NMR pulse sequence which employs a potentially more efficient and chemical shift independent excitation scheme is described. Results obtained with the modified experiment are illustrated using the complex alkaloid gelsemine. Two new pulse sequences which provide $F\sb1$ homonuclear decoupling double quantum filtered zero quantum 2D-NMR spectra are introduced. One of the pulse sequences uses a chemical shift dependent excitation scheme while the second uses a chemical shift independent sequence. The effects of composite 180$\sbsp{y}{o}$ pulses during the excitation and evolution of zero quantum coherences are explored. The effectiveness of a magnetic field homogeneity spoiling pulses on the signal intensity of zero quantum resonances is investigated as is the effect of the tip angle of the radio frequency conversion pulse, $\alpha$. Double quantum filtered, $F\sb1$ proton homodecoupled zero quantum relayed coherence transfer is discussed and a new pulse sequence described. The pulse sequence provides a mechanism for exploring remote proton-proton connectivities. The mapping of the two four spin systems of the helicene derived phenanthro (3$\sp\prime$,4$\sp\prime$:3,4) phenanthro (2,1-b) thiophene is discussed in the context of zero quantum relay. A remote 5-bond "W" connectivity is observed for phenanthro (4,3-a) dibenzothiophene. Heteronuclear $\sp{13}$C-$\sp{31}$P chemical shift correlation via heteronuclear multiple quantum coherence is described. Enhanced sensitivity is afforded by the inverse detection of $\sp{31}$P rather than detection of the much less abundant $\sp{13}$C spin. Correlations via $\sp1J\sb{CP}$ and $\sp{n}J\sb{CP}$ where n = 2, 3, are observed with minor variations in the pulse sequence. A description of the laboratory built probes and X-band decoupler is also presented.

Macroscopic synthetic techniques for producing fullerene molecules have been developed which include the carbon arc and laser vaporization approaches. The "pentagon rule" kinetic growth mechanism for the fullerenes is proposed to explain this facile process. The reactor technology for generating fullerene molecules is generalized. Resonant two-photon ionization measurements have yielded the triplet state lifetimes and electronic spectroscopy of C$\sb{60}$ and C$\sb{70}$ in a supersonic molecular beam. The technique and results are described in detail. An unusual type of C$\sb{60}$ $\cdot$ Ar$\sp{+}$ complex has been detected through fragmentation studies in a tandem time-of-flight mass spectrometer. Rotational stabilization is proposed as the mechanism leading to the long lifetime of this and similar species.

While azoalkanes are normally employed as convenient sources of radicals and biradicals, radical cation salts such as tris-(4-bromophenyl)aminium hexachloroantimonate and thianthrenium perchlorate oxidize azoalkanes under mild conditions to products characteristic of alkyl cations. A survey of N$\sb2$ yields for oxidation of twenty azoalkanes was conducted to compare their reactivity. Detailed product studies were conducted on selected azoalkanes in order to derive a general mechanism and to rationalize the effect of azoalkane structure on reactivity. A slower secondary decomposition observed for both azo-t-octane and 3,3,6,6-tetramethyl-1,2-diazacyclohexene was attributed to an oxidant containing the anion of these radical cations. Replacement of these "oxidizing" anions (SbCl$\sb{6\sp-}$, ClO$\sb{4\sp-}$) with "non-oxidizing" anions (SbF$\sb{6\sp-}$, BF$\sb{4\sp-}$) prevented the secondary decomposition of these azoalkanes. Tertiary azoalkanes that form an unstrained radical and cation reacted with two equivalents of radical cation salt affording a quantitative yield of N$\sb2$ and two equivalents of cation-derived products. For bridgehead azoalkanes, the N$\sb2$ yield decreased as the strain in the incipient radical and cation increased, an effect attributed to diversion of the more reactive radicals from oxidation to hydrogen abstraction. Cis to trans isomerization of azo-1-norbornane was observed with a catalytic amount of radical cation, but no N$\sb2$ was lost even when the radical cation was in two-fold excess. Replacement of an "oxidizing" anion with a "non-oxidizing" anion in the reaction of a radical cation with azo-1,1$\sp\prime$-adamantane warrants the reinvestigation of this reaction which involved the "oxidizing" anion. Rather than losing N$\sb2$, 2,3-diazabicyclo (2.2.2) oct-2-ene formed a red salt with the radical cation, but replacing both bridgehead hydrogens with methyl groups again led to N$\sb2$ loss. The analogous compound with only one bridgehead methyl group exhibited both N$\sb2$ loss and adduct formation. The reactivity of an azoalkane was shown to depend upon its structure as well as the structure of its incipient alkyl cation. An electrophilic mechanism was favored over a single electron transfer mechanism because oxidation of azoalkanes by these radical cation salts appears to be endothermic.

The new third form of carbon, known collectively as fullerenes, is studied in several general aspects. Efficient production methods have been developed along with an increased understanding into the formation mechanisms. Several physical and chemical properties are investigated in attempts to characterize these unique molecules. An exciting feature of these all-carbon molecules is their ability to undergo chemical modification while maintaining their cage structure, unlike diamond or graphite. One of the fundamental alterations is the addition of oxygen atoms to the cage. Techniques to produce these derivatives and their characterization is also presented.

Herein is described the synthesis and assembly of compounds designed to advance the fields of surface science and molecular electronics. The first series of compounds are based on a phenanthrene core and are terminated with a thioacetate moiety which allows for assembly onto metallic surfaces. Eight polyaromatic compounds were synthesized to examine the role of internal rotation in electrical switching as observed by a scanning tunneling microscope (STM). It was thought that internal rotation, which disrupts the molecule's conjugation, was responsible for the switching behavior. One of these polyaromatic compounds (2-thioacetyl-phenanthrene) as well a biphenyl control (4-thioacetobiphenyl) were examined in a STM testbed. The polyaromatic compound (which cannot rotate) showed switching allowing internal rotation to be ruled out as a mechanism for switching as seen by STM. A second series of compounds, organic thiocyanates, were synthesized to examine their assembly onto metallic surfaces. It was found that this class of compounds assembles onto metallic surfaces under ambient conditions. The resultant monolayer contains the same thiolate-gold bond seen when assembling from the free thiol. The mechanism for this assembly involves surface-mediated conversion of the thiocyanate to a thiolate and M(CN)ads followed by expulsion of the cyanide from the surface as a metal salt ([M(CN) 2]- or [M(CN)4]2-). Comparable free thiol assembles are oxidatively unstable and are prone to disulfide formation. In the case of alpha,o-dithiols, polymerization is often seen. Thiocyanates are advantageous as they are stable and require neither exogenous material for the assembly nor oxygen free conditions. Finally, a series of transition metal complexes designed to assemble on gold surfaces was synthesized. This bis(2,5-di-[2]pyridyl-3,4-dithiocyanto-pyrrolate) metal complex was prepared with zinc, copper, nickel, cobalt, and iron. The electronic structure and transitions of these compounds were studied by UV-vis and their magnetic properties studied by EPR and SQUID magnetometer. These molecules were then assembled onto a gold surface taking advantage of the above thiocyanate assembly protocol. The assembly process gives a loosely packed monolayer with no sign the compound had disproportionated or decomposed. This molecular assembly was used in single molecule transistors (SMTs) and allowed for examination of the Kondo effect.

The objectives of this research were to study metabolic pathways in C. roseus hairy root cultures, and to enhance secondary metabolite productivity using fungal elicitation as the technique. The effects of age of inoculum were studied by adapting the cultures to three subculture cycle routines. The 2 week subculture cycle yielded the fastest, while the 4 week cycle yielded the lowest, specific growth rates. Specific yields of tabersonine decreased from day 21 to 35 while the total yields of horhammericine increased in all three subculture cycles. Lochnericine yields were highest in the 2 week cycle while serpentine yields were lowest. The effects of dosages and exposure times of specific elicitors on several compounds in the indole alkaloid pathway were studied. A 150% increase in tabersonine specific yield was observed upon addition of 72 units of pectinase. Levels of serpentine, tabersonine and lochnericine decreased transiently after addition of pectinase in time course studies. Jasmonic acid was found to be a unique elicitor leading to an enhancement in flux to several branches in the alkaloid pathway. Time course studies with jasmonic acid showed a transient increase in lochnericine and tabersonine levels and a continuous increase in levels of ajmalicine, serpentine and horhammericine. NMR spectroscopy was utilized as the tool to study primary metabolism of hairy roots non-invasively. $\sp{31}$P NMR spectroscopy studies indicated that vacuolar and cytoplasmic pH were maintained at 7.4 $\pm$ 0.06 and 5.25 $\pm$ 0.08 respectively. $\sp{13}$C NMR spectroscopy studies indicated activities of pentose phosphate pathways, non-photosynthetic CO$\sb2$ fixation and glucan synthesis pathways. Recycling of triose phosphate was evident from scrambling of label in glucans. In vivo $\sp{31}$P and $\sp{13}$C NMR spectroscopy was subsequently utilized to study the effects of elicitors on primary metabolism. A transient short-term decline in the cytoplasmic pH was observed upon addition of pectinase while a prolonged decrease in vacuolar pH was observed upon addition of jasmonic acid. Enhanced accumulation of glucans was detected upon addition of pectinase. A reduction in the levels of pyruvate and glutamine was observed, upon addition of jasmonic acid, indicating a decrease in flux to glycolysis or an increase in the drain on these pools.

A new widely tunable mid-infrared (IR) source based on difference-frequency generation (DFG) in Gallium Selenide (GaSe) for use in high-resolution spectroscopy and trace gas detection is described. The characteristics of type-I phasematching in GaSe are studied. Preliminary results on the improvement of the dispersion relations for GaSe are presented. Spectroscopic feasibility experiments are reported that involve the spectroscopy of ethylene $\rm (C\sb2H\sb4)$ at low pressures near 950 $\rm cm\sp{-1}.$ Two near-IR Ti:Sapphire lasers served as convenient pump sources, which can be eventually replaced by two high power near-IR diode lasers. Design issues (including optimum elliptical focusing conditions), potential improvements and new directions are also discussed.

This dissertation presents solid-state NMR studies of the chain conformation, dynamics and morphology of three adsorbed polymer systems: two random semi-crystalline copolymers, poly(ethylene-co-acrylic acid) (PEA) and poly(propylene-co-acrylic acid) (PPA), and an amorphous homopolymer, poly(n-butyl methacrylate) (PnBMA). Zirconia (ZrO2) was chosen as the substrate for all three polymers since the binding of carboxylic acids to this metal oxide is well understood. The choice of polymers was based on their particular bulk conformational and dynamic properties as well as their common use in polymer coatings. These studies are motivated by the general lack of a microscopic picture of adsorbed polymers, which can be provided by NMR, and the relevance of chain conformation and dynamics to important polymer film properties such as adhesion. / First the chain conformation and surface binding of adsorbed PEA as a function of acrylic acid content are characterized by 13C cross polarization - magic angle spinning (CP-MAS), 2D 1H- 13C wideline separation (WISE) and 1H spin diffusion NMR experiments and FTIR-PAS (Fourier transform infrared photoacoustic spectroscopy) measurements. The most important finding is that the chain conformation of adsorbed PEA is determined primarily by the sticker group density rather than the surface coverage. The second study of PEA concerns the chain dynamics in the bulk and adsorbed states. Variable temperature NMR experiments provide evidence that ethylene segments of adsorbed PEA form partially folded loops rather than flat extended trains. Finally 129Xe NMR studies, used to probe the morphology of adsorbed PEA, show a bulk-like signal only for the highest loadings. / The second system investigated, PPA, is another semi-crystalline random copolymer which binds to zirconia via carboxylate linkages. The 13 C CP-MAS NMR spectra of adsorbed PPAC unexpectedly show splittings normally associated with chain-chain packing in the crystalline regions of bulk polypropylene (PP). The splittings in the spectra of adsorbed PPAC, which are more resolved than in bulk PPA, are proposed to arise from recrystallization of the PP segments between sticker groups. / Finally the interfacial properties of an amorphous homopolymer, PnBMA were studied using 13C and 129Xe NMR to characterize adsorbed and filled samples. PnBMA binds to zirconia via the partial hydrolysis of the ester side chains. The remaining ester chains of adsorbed PnBMA are found to segregate to the polymer/air interface. Both adsorbed and ZrO 2-filled PnBMA show enhanced local segmental mobility. However, the 129Xe NMR measurements of the filled samples are consistent with restricted motion on a larger length scale which may be due to particle bridging.