NiSi is an attractive material in the production of CMOS devices. The problem with the utilization of NiSi, is that there is no proper method of cleaning the oxide on the surface. Sputtering is the most common method used for the cleaning, but it has its own complications. Dry cleaning methods include the reactions with radicals and these processes are not well understood and are the focus of the project. Dissociated NF3 and NH3 were used as an alternative and XPS is the technique to analyze the reactions of atomic fluorine and nitrogen with the oxide on the surface. A thermal cracker was used to dissociate the NF3 and NH3 into NFx+F and NHx+H. There was a formation of a NiF2 layer on top of the oxide and there was no evidence of nitrogen on the surface indicating that the fluorine and hydrogen are the reacting species. XPS spectra, however, indicate that the substrate SiO2 layer is not removed by the dissociated NF3 and NiF2 growth process. The NiF2 over layer can be reduced to metallic Ni by reacting with dissociated NH3 at room temperature. The atomic hydrogen from dissociated ammonia reduces the NiF2 but it was determined that the …

The kinetics of the reaction of atomic sulfur with acetylene (S (3P) + C2H2) were investigated experimentally via the flash photolysis resonance fluorescence method, and the theoretical potential energy surface for the reaction CN + SO was modeled via the density functional and configuration interaction computational methods. Sulfur is of interest in modern chemistry due to its relevance in combustion and atmospheric chemistry, in the Claus process, in soot and diamond-film formation and in astrochemistry. Experimental conditions ranged from 295 – 1015 K and 10 – 400 Torr of argon. Pressure-dependence was shown at all experimental temperatures. The room temperature high-pressure limit second order rate constant was (2.10 ± 0.08) × 10-13 cm3 molecule-1 s-1. The Arrhenius plot of the high-pressure limit rate constants gave an Ea of (11.34 ± 0.03) kJ mol-1 and a pre-exponential factor of (2.14 ± 0.19) × 10-11 cm3 molecule-1 s-1. S (3P) + C2H2 is likely an adduct forming reaction due to pressure-dependence (also supported by a statistical mechanics analysis) which involves intersystem crossing. The potential energy surface for CN + SO was calculated at the B3LYP/6-311G(d) level and refined at the QCISD/6-311G(d) level. The PES was compared to that of the analogous reaction …

The potential use of polymeric, functionalized nanoparticles (NPs) as drug delivery vectors was explored. Covalent conjugation of albumin to the surface of NPs via maleimide chemistry proved problematic. However, microwave assisted synthesis of NPs was not only time efficient, but enabled the exploration of size control by changing the following parameters: temperature, microwave power, reaction time, initiator concentration, and percentage of monomer used. About 1.5 g of fluorescently-labeled, carboxylic acid-functionalized NPs (100 nm diameter) were synthesized for a total cost of less than $1. Future work will address further functionalization of the NPs for the coupling of albumin (or other targeted proteins), and tests for in vivo biodistribution.

Combinatorial libraries are used in the search for ligands that bind to target proteins. Fmoc solid-phase peptide synthesis is routinely used to generate such libraries. Microwave-assisted peptide synthesis was employed here to decrease reaction times by 80-90%. Two One-Bead-One-Compound combinatorial libraries were synthesized on 130μm beads (one containing 750 members and the other 16, 807). The use of smaller solid supports would have many important practical advantages including; increased library diversity per unit mass, smaller quantities of library needed to generate hits, and screening could be conducted by using a standard flow cytometer. To this end, a miniaturized peptide library was synthesized on 20 μm beads to demonstrate proof of principle. A small sample from the 16,807-member library was screened against transferrin-AlexaFluro 647, a protein responsible for iron transport in vivo. A number of hits were identified and sequenced using techniques coupling nanomanipulation with nanoelectrospray mass spectrometry.

Two aluminum spherical mirrors with radii of 203.2 mm and radii of curvature also of 203.2 mm have been used to construct a tunable Fabry-Perót type resonator operational at frequencies as low as 500 MHz. The resonator has been incorporated into a pulsed nozzle, Fourier transform, Balle-Flygare spectrometer. The spectrometer is of use in recording low J transitions of large asymmetric molecules where the spectra are often greatly simplified compared to higher frequency regions. The resonators use is illustrated by recording the rotational spectra of bromobenzene and iodobenzene. In related experiments, using similar equipment, the pure rotational spectra of four isotopomers of SrS and all three naturally occurring isotopomers of the actinide-containing compound thorium monoxide have been recorded between 6 and 26 GHz. The data have been thoroughly analyzed to produce information pertaining to bond lengths and electronic structures.

Presented in this thesis are two methods that are coupled to the instrumentation for the recovery and analysis of ultra-trace illicit drug residues. The electrostatic dust lifting process is coupled with nanomanipulation-nanospray ionization to retrieve drug particles off of hard surfaces for analysis. For the second method, drug residues from fingerprint impressions are extracted followed by analysis. The methodology of these hyphenated techniques toward forensic science applications is applied as to explore limits of detection, sensitivity, and selectivity of analytes as well as immediacy and efficiency of analysis. The application of nanomanipulation-coupled to nanospray ionization-mass spectrometry toward forensic science based applications is considered as future improvements to trace and ultra-trace analysis.

The reaction between the formamidine ligand PriN=CHNHPri and the activated cluster Os3(CO)10(MeCN)2 has been studied. A rapid reaction is observed at room temperature, yielding the hydride clusters HOs3(CO)9[μ-OCNPriC(H)NPri] and HOs3(CO)10[μ-NPriC(H)NPri] as the principal products. The spectroscopic data and X-ray diffraction structures of those formamidinate-substituted clusters will be present. The thermal reactivity of the clusters has been investigated, with the face-capped cluster HOs3(CO)9[μ-NPriC(H)NPri] found as the sole observable product. The relationship between these three clusters has been established by kinetic studies, the results of which will be discussed.

Preparative mass spectrometry is an important method for the synthesis of new materials. Recently, soft landing mass spectrometry has been used to land ions on surfaces to coat or otherwise alter them. Commercial soft landing instruments do not yet exist, and the physical phenomenon of soft landing has not yet been fully described. For future ion mobility soft landing research, the theory of ion mobility, ion optics and soft landing is discussed, and 2 soft landing instruments have been built and described, along with proof of concept experiments for both instruments. Simulations of the process of ion mobility and ion optics for use in these instruments, as well as some preliminary results for the optics are included. Surfaces described include copper on mica and iron on silicon. Self assembly of soft landed ions is observed on the surfaces. The instruments constructed will be useful for future soft landing research, and soft landing can be used for future materials research with special attention focused on the self-assembly of the landed ions.

The Abraham solvation parameter model is a good approach for analyzing and predicting biological activities and partitioning coefficients. The general solvation equation has been used to predict the solute property (SP) behavior of drug compounds between biological barriers. Gas chromatography (GC) retention time can be used to predict molecular descriptors, such as E, S, A, B & L for existing and newly developed drug compounds. In this research, six columns of different stationary phases were used to predict the Abraham molecular descriptors more accurately. The six stationary phases used were 5% phenylmethyl polysiloxane, 6% cyanopropylphenyl 94% dimethylpolysiloxane, 5% diphenyl 95% dimethylpolysiloxane, 100% dimethylpolysiloxane, polyethylene glycol and 35% diphenyl 65% dimethylpolysiloxane. Retention times (RT) of 75 compounds have been measured and logarithm of experimental average retention time Ln(RTexp) are calculated. The Abraham solvation model is then applied to predict the process coefficients of these compounds using the literature values of the molecular descriptors (Acree Compilation descriptors). Six correlation equations are built up as a training set for each of the six columns. The six equations are then used to predict the molecular descriptors of the illegal drugs as a test set. This work shows the ability to extract molecular information from …

The details of dye sensitized solar cells was explained and phenothiazine and porphyrin based dyes were synthesized for use in DSSCs. DSSCs offer a unique and cost effective method of renewable energy. DSSCs are characterized through various tests, with the overall efficiency, η, bearing the greatest importance. Incident photon to current conversion efficiency, or IPCE, is also another important characterization of DSSCs. Effect of positioning of the cyanoacrylic acid anchoring group on ring periphery of phenothiazine dye on the performance of dye sensitized solar cells (DSSCs) is reported. The performances of the cells are found to be prominent for solar cells made out of Type-1 dyes compared to Type-2 dyes. This trend has been rationalized based on spectral, electrochemical, computational and electrochemical impedance spectroscopy results. Free-base and zinc porphyrins bearing a carboxyl anchoring group at the para, meta, or ortho positions of one of the meso-phenyl rings were synthesized for DSSCs. Photoelectrochemical studies were performed after immobilization of porphyrins onto nanocrystalline TiO2. The performance of DSSCs with the porphyrin anchoring at the para or meta position were found to greatly exceed those in the ortho position. Additionally, zinc porphyrin derivatives outperformed the free-base porphyrin analogs, including better dye regeneration efficiency …

The world is facing a tough challenge regarding fulfilling human energy needs. Scientists are motivated to find alternative ways to the fossil fuel at a lower cost with little or no environmental pollution. Among the available renewable resources, the solar energy is an alternative energy to fossil fuel. Scientists are engaged in mimicking the photosynthesis to create the new energy devices such as dye sensitized solar cells. The fundamental theory and properties of the dye sensitized solar cells is given in the first chapter. In this research, the application of the different methods for surface alteration of SnO2 with water soluble porphyrins and phthalocyanine is studied. Using optical absorbance and steady state fluorescence studies, the formation of porphyrins and phthalocyanine discuss on the SnO2 surface is shown. Moreover, the different results of photoelectrochemical cells are show on chapter 2 to understand the porphyrin and phthalocyanine modified on SnO2 as electron injector. In summary, the application porphyrin and phthalocyanine of dimers as a broad band capturing photosensitized dye is discussed.

Photoinduced electron transfer in self-assembled via axial coordination porphyrin-fullerene dyads is investigated. Fullerene functionalized with imidazole and fullerenes functionalized with pyridine are chosen as electron acceptors, while zinc pophyrin derivatives are utilized as electron donors. The electron withdrawing ability of halogen atoms make the porphyrin ring electrophilic, which explained the binding of (F20TPP)Zn with fullerene derivatives having the highest binding constant around 105M-1. Another important observation is that the fullerene imidazole binding to zinc pophyrin had higher stability than fullerene pyridine-porphyrin dyad. Computational DFT B3LYP-21G(*) calculations are used to study the geometric and electronic structures. The HOMO and LUMO was found to be located on the porphyrin and fullerene entities, respectively. Photoinduced electron transfer is investigated by the steady-state absorption and emission, differential pulse voltammetry, and nanosecond and femtosecond transient absorption studies. The measurements provided the same conclusion that the increasing number of the halogen atoms on the porphyrin ring leads to the higher binding of porphyrin-fullerene supramolecular dyads and efficient charge separation and charge recombination processes.

Syntheses of diphosphine gold (I) complexes from gold THT and two ligands, 4, 5-bis (diphenylphosphino)-4-cyclopenten-1, 3-dione (BPCD) and 2,3-bis(diphenylphosphino)-N-phenylmaleimide (BPPM), were done separately. The reactions happened under ice conditions followed by room temperature conditions and produced two diphosphine gold (I) complexes in moderated yield. Spectroscopic results including nuclear magnetic resonance (NMR) and X-ray crystallography were used to study and determine the structures of the products formed. Moreover, X-rays of all newly synthesized diphosphine gold (I) complexes were compared with the known X-ray structures of other phosphine and diphosphine gold (I) complexes. There were direct resemblances in terms of bond length and angle between these new diphosphine gold (I) complex structures and those already published. For instance, the bond lengths and angles from the newly prepared diphosphine gold (I) complexes were similar to those already published. Where there were some deviations in bond angles and length between the newly synthesized structures and those already published, appropriate explanation was given to explain the deviation. Heterocyclic ligands bearing acetylacetonate (ACAC) side arm(s) were prepared from ethyl malonyl chloride and the heterocyclic compounds 8-hydroxylquinoline, Syn-2-peridoxyaldoxime, quinoxalinol and 2, 6-dipyridinylmethanol. The products (heterocyclic ACAC ligands) from these reactions were screened with transition metal carbonyl compounds …

This study expands the role of polythiophenes as an electron donating chromophore within energy harvesting milti-modular donor-acceptor systems. The polythiophene moiety would act as an electron donating spacer group between the donor and acceptor entities, viz., phenothiazine and fulleropyrrolidine, respectively, in the newly synthesized supramolecular triads. The triads 10-{[2,2';5',2"] terthiophene-5-fulleropyrrolidine} phenothiazine and 10-{[2,2'] bithiophene-5-fulleropyrrolidine} phenothiazine were synthesized and characterized through electrochemical and spectroscopic methods to ascertain their structural integrity. the componets of the triads were selected for their established redox parameters. Phenothiazine would act as a secondary donor and would facilitate hole-transfer from the polythiophene primary electron donor, due to its ease of oxidation and yield a long-lived charge separated state. Fulleropyrrolidine would act as an acceptor for ease of reductive capabilities and its ability to hold multiple charges. Finally, occurrence of photoinduced electron transferleading to the anticipated charge separated states is established from advanced transient spectroscopic techniques on these novel supramolecular systems.

Laser Ablation Inductively coupled plasma mass spectrometry (LA-ICP-MS) and Raman spectroscopy are both powerful imaging techniques. Their applications are numerous and extremely potential in the field of biology. In order to improve upon LA-ICP-MS an in-house built cold cell was developed and its effectiveness studied by imaging Brassica napus seeds. To further apply LA-ICP-MS and Raman imaging to the field of entomology a prong gilled mayfly (Ephemeroptera: Leptophlebiidae) from the Róbalo River, located on Navarino Island in Chile, was studied. Analysis of both samples showcased LA-ICP-MS and Raman spectroscopy as effective instruments for imaging trace elements and larger molecules in biological samples respectively.

Organometallic catalysis has attracted significant interest from both industry and academia due to its wide applications in organic synthetic transformations. Example of such transformations include the reaction of a zinc carbenoid with olefins to form cyclopropanes. The first project is a computational study using both density functional and correlated wavefunction methods of the reaction between ethylene and model zinc carbenoid, nitrenoid and oxenoid complexes (L-Zn-E-X, E = CH2, NH or O, L = X = I or Cl). It was shown that cyclopropanation of ethylene with IZnCH2I and aziridination of ethylene with IZnNHI proceed via a single-step mechanism with an asynchronous transition state. The reaction barrier for the aziridination with IZnNHI is lower than that of cyclopropanation. Changing the leaving group of IZnNHI from I to Cl, changes the mechanism of the aziridination reaction to a two-step pathway. The calculation results from the epoxidation with IZnOI and ClZnOCl oxenoids suggest a two-step mechanism for both oxenoids. Another important example of organometallic catalysis is the formation of alkyl arenes from arenes and olefins using transition metal catalysis (olefin hydroarylation). We studied with DFT methods the mechanism of a novel Rh catalyst (FlDAB)Rh(TFA)(η2–C2H4) [FlDAB = N,N’ -bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA = trifluoroacetate] that converts …

While computational chemistry methods have a wide range of applications within the set of traditional physical sciences, very little is being done in terms of expanding their usage into other areas of science where these methods can help clarify research questions. One such promising field is Forensic Science, where detailed, rapidly acquired sets of chemical data can help in decision-making at a crime scene. As part of an effort to create a database that fits these characteristics, the present work makes use of computational chemistry methods to increase the information readily available for the rapid identification and scheduling of drugs to the forensic scientist. Ab initio geometry optimizations, vibrational spectra calculations and ESI-MS fragmentation prediction of a group of common psychedelics are here presented. In addition, we describe an under development graphical user interface to perform ab initio calculations using the GAMESS software package in a more accessible manner. Results show that the set of theoretical techniques here utilized, closely approximate experimental data. Another aspect covered in this work is the implementation of a boiling point estimation method based on group contributions to generate chemical dispersion areas with the ALOHA software package. Once again, theoretical results showed to be in …

Experimental data were obtained for the computation of mole fraction solubilities of three dichloronitrobenzenes in organic solvents at 25oC, and solubility ratios were obtained from this data. Abraham model equations were developed for solutes in tributyl phosphate that describe experimental values to within 0.15 log units, and correlations were made to describe solute partitioning in systems that contain either "wet" or "dry" tributyl phosphate. Abraham model correlations have also been developed for solute transfer into anhydrous diisopropyl ether, and these correlations fit in well with those for other ethers. Abraham correlations for the solvation of enthalpy have been derived from experimental and literature data for mesitylene, p-xylene, chlorobenzene, and 1,2-dichlorobenzene at 298.15 K. In addition, the enthalpy contribution of hydrogen bonding between these solutes and acidic solvents were predicted by these correlations and were in agreement with an established method. Residual plots corresponding to Abraham models developed in all of these studies were analyzed for trends in error between experimental and calculated values.

The kinetics of the gas-phase reactions of chlorine atoms with fluoromethane (CH3F) and fluoromethane-d3(CD3F) were tested experimentally. The relative rate method was applied by using CH4 as the reference compound for fluoromethane (CH3F) and CH4 and CH3F as the reference compound for fluoromethane-d3(CD3F). The rate constants for H-abstraction from CH3F and D-abstraction from CD3F were measured at room temperature and a total pressure of 920 Torr using Ar as a diluent. The rate constants are described by the expressions: kH= (3.50±0.52) x 10-13 cm3 molecule-1 s-1 and kD=(5.0±0.51) x 10-14 cm3 molecule-1 s-1. The kinetic isotope effect, equal to the ratio kH/kD, was found to be 7.0±1.2 at room temperature.

The reaction of the chelating ligand 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl]-N,N-diethyl-benzenamine, L, with pentacarbonylchlororhenium by conventional heating method produces the complexes fac-[ReL(CO)3Cl2] and fac-[Re2L(CO)6Cl2] in a period of 48 hours. The use of microwaves as the source of heat and the increase in the equivalents of one of the reactants leads to a more selective reaction and also decreases the reaction time to 1 hour. After proper purification, the photophysical properties of fac-[ReL(CO)3Cl] were analyzed. The solid-state photoluminescence analysis showed an emission band at 628 nm independent of temperature. However, in the solution studies, the emission band shifted from 550 nm in frozen media to 610 nm when the matrix became fluid. These results confirm that this complex possess a phenomenon known as rigidochromism.

A series of heteroleptic and homoleptic platinum(II) complexes has been synthesized and characterized towards their use in thin film devices such as organic light-emitting diodes (OLEDs) and organic thin film transistors (OTFTs). Pyridylpyrazolate- and pyridyltetrazolate-containing ligands were selected due to their structural rigidity and ease of functionalization. Single-crystal x-ray diffraction studies of two selected heteroleptic complexes show strong aggregation with preferential stacking into vertical columns with a varying degree of overlap of the neighboring square planar molecular units. It is shown that the close proximity of the molecules to one another in the stack increases semiconducting character, phosphorescence quantum yields, and shorter radiative lifetimes. The potential for these materials towards incorporation into high-efficiency doping free white OLEDs (DFW-OLEDs) for solid-state lighting and display applications has been realized and will be expanded upon by present and future embodiments of materials in this thesis.

Portable mass spectrometry has become an important analytical tool for chemical detection and identification outside of a lab setting. Many variations and applications have been developed to benefit various fields of science. Membrane inlet mass spectrometry is used to allow certain analytes to pass into the mass spectrometer without breaking vacuum or letting in large particulate matter. These two important analytical tools have been applied to the detection of harmful chemicals in the air. Earth-based separations and reverse gas stack modelling are useful mathematical tools that can be used to locate the source of a chemical release by back calculation. Earth-based separations studies the way different molecules will diffuse and separate through the air. Reverse gas stack modelling refers to the concentration differences of a chemical in relation to its distance from its source. These four analytical techniques can be combined to quickly and accurately locate various harmful chemical releases. The same system can be used for many applications and has been tested to detect harmful chemicals within and air-handling system. The monitoring of air-handling systems can greatly reduce the threat of harm to the building occupants by detecting hazardous chemicals and shutting off the air flow to minimize human …

The growth of Co (0001) films and Cr2O3 (0001)/Co (0001) has been investigated using surface analysis methods. Such films are of potential importance for a variety of spintronics applications. Co films were directly deposited on commercial Al2O3 (0001) substrates by magnetron sputter deposition or by molecular beam epitaxy (MBE), with thicknesses of ~1000Å or 30Å, respectively. Low Energy Electron Diffraction (LEED) shows hexagonal (1x1) pattern for expected epitaxial films grown at 800 K to ensure the hexagonally close-packed structure. X-ray photoemission spectroscopy (XPS) indicates the metallic cobalt binding energy for Co (2p3/2) peak, which is at 778.1eV. Atomic force microscopy (AFM) indicates the root mean square (rms) roughness of Co films has been dramatically reduced from 10 nm to 0.6 nm by optimization of experiment parameters, especially Ar pressure during plasma deposition. Ultrathin Cr2O3 films (10 to 25 Å) have been successfully fabricated on 1000Å Co (0001) films by MBE. LEED data indicate Cr2O3 has C6v symmetry and bifurcated spots from Co to Cr2O3 with Cr2O3 thickness less than 6 Å. XPS indicates the binding energy of Cr 2p(3/2) is at 576.6eV which is metallic oxide peak. XPS also shows the growth of Cr2O3 on Co (0001) form a thin …

The efficiency and mechanism of electron- and energy transfer events occurring in both in natural and synthetic donor-acceptor systems depend on their distance, relative orientation, and the nature of the surrounding media. Fundamental knowledge gained from model studies is key in building efficient energy harvesting and optoelectronic devices. Faster charge separation and slower charge recombination in donor-acceptor systems is often sought out. In our continued effort to build donor-acceptor systems using near-IR sensitizers, in the present study, we report ground and excited state charge transfer in newly synthesized, directly linked, tetrads featuring bisdonor (donor = phenothiazine and ferrocene), BF2-chelated azadipyrromethane (azaBODIPY) and C60 entities. The tetrads synthesized using multi-step synthetic procedure revealed strong charge transfer interactions in the ground state involving the donor and azaBODIPY entities. The near-IR emitting azaBODIPY acted as a photosensitizing electron acceptor along with fullerene while the phenothiazine and ferrocene entities acted as electron donors. The triads (bisdonor-azaBODIPY) and tetrads revealed ultrafast photoinduced charge separation leading to D•+-azaBODIPY•–-C60 and D•+-azaBODIPY-C60•– (D = phenothiazine or ferrocene) charge separated states from the femtosecond transient absorption spectral studies in both polar and nonpolar solvent media. The charge separated states populated the triplet excited state of azaBODIPY prior returning to …