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Substituent Effects: A Computational Study on Stabilities of Cumulenes and Low Barrier Hydrogen Bonds

Description: The effect of substituents on the stabilities of cumulenes-ketenes, allenes, diazomethanes and isocyanates and related systems-alkynes, nitriles and nitrile oxides is studied using the density functional theory (B3LYP, SVWN and BP86) and ab initio (HF, MP2) calculations at the 6-31G* basis set level. Using isodesmic reactions, correlation between stabilization energies of cumulenes and substituent group electronegativities (c BE) is established and the results from DFT and MP2 methods are compa… more
Date: August 2000
Creator: Kumar, Ganesh Angusamy
Item Type: Refine your search to only Thesis or Dissertation

Diphosphine Ligand Activation Studies with Organotransition-Metal Compounds

Description: Thermolysis of CoRu(CO)7(m -PPh2) (1) in refluxing 1,2-dichloroethane in the presence of the diphosphine ligands 2,3-bis(diphenylphosphino)maleic anhydride (bma) and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) furnishes the new mixed-metal complexes CoRu(CO)4(μ -P-P)(μ -PPh2) [where P-P = bma (3); bpcd (6)], along with trace amounts of the known complex CoRu(CO)6(PPh3)(μ -PPh2) (4). The requisite pentacarbonyl intermediates CoRu(CO)5(μ -P-P)(μ -PPh2) [where P-P = bma (2); bpcd (5)… more
Date: December 2000
Creator: Wang, Jiancheng
Item Type: Refine your search to only Thesis or Dissertation

Layered Double Hydroxides and the Origins of Life on Earth

Description: A brief introduction to the current state of research in the Origins of Life field is given in Part I of this work. Part II covers original research performed by the author and co-workers. Layered Double Hydroxide (LDH) systems are anion-exchanging clays that have the general formula M(II)xM(III)(OH)(2x+2)Y, where M(II) and M(III) are any divalent and trivalent metals, respectively. Y can be nearly any anion, although modern naturally occuring LDH systems incorporate carbonate (CO32-), chloride… more
Date: May 2001
Creator: Brister, Brian
Item Type: Refine your search to only Thesis or Dissertation

Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-Methoxyimines

Description: The second order rate constants for nucleophilic substitution by methoxide of (Z)- and (E)-O-methylbenzohydroximoyl fluorides [C6H4C(F)=NOCH3] with various substituents on the phenyl ring [p-OCH3 (1h, 2h), p-CH3 (1g, 2g), p-Cl (1f, 2f), p-H (1e, 2e), (3,5)-bis-CF3 (1i, 2i)] in 90:10 DMSO:MeOH have been measured. A Hammett plot of these rate constants vs σ values gave positive ρ values of 2.95 (Z isomer) and 3.29 (E isomer). Comparison of these rates with methoxide substitution rates for Ometh… more
Date: December 2001
Creator: Dolliver, Debra D.
Item Type: Refine your search to only Thesis or Dissertation

Layered Double Hydroxides: Morphology, Interlayer Anion, and the Origins of Life

Description: The preparation of layered double hydroxides via co-precipitation of a divalent/trivalent metal solution against a base results in 1 mm LDH particles with a disorganized metal lattice. Research was performed to address these morphological issues using techniques such as Ostwald ripening and precipitation via aluminate. Another interesting issue in layered double hydroxide materials is the uptake and orientation of anions into the interlayer. Questions about iron cyanide interlayer anions have b… more
Date: December 2002
Creator: Halcom-Yarberry, Faith Marie
Item Type: Refine your search to only Thesis or Dissertation

Investigations of Thermochemistry and the Kinetics of H Atom Radical Reactions

Description: The thermochemistry of several species, and the kinetics of various H atom radical reactions relevant to atmospheric and combustion chemistry were investigated using ab initio theoretical techniques and the flash photolysis / resonance fluorescence technique. Using ab initio quantum mechanical calculations up to the G3 level of theory, the C-H bond strengths of several alkanes were calculated. The bond strengths were calculated using two working reactions. From the results, it is apparent that … more
Date: December 2002
Creator: Peebles, Lynda Renee
Item Type: Refine your search to only Thesis or Dissertation

Synthesis and X-ray Diffraction Structure of 8,9-Dichloropyrrolo[1,2-a]perimidin-10-one

Description: Treatment of dichloromaleic anhydride and 1,8-diaminonaphthalene in either benzene or toluene under refluxing conditions gives low yields of the new heterocyclic compound 8,9-dichloropyrrolo[1,2-a]perimidin-10-one. This product has been isolated and characterized in solution by NMR, IR, and UV/vis spectroscopies, and the solid-state structure of 8,9-dichloropyrrolo[1,2-a]perimidin-10-one has been established by X-ray crystallography. The nature of the HOMO and LUMO levels of 8,9-dichloropyrrolo… more
Date: August 2003
Creator: Chen, Tao
Item Type: Refine your search to only Thesis or Dissertation

Baeyer-Villiger Oxidation of 1,7- & 1,9-dibromopentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione

Description: Baeyer-Villiger oxidation of 1,9-dibromopentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione (1,9-dibromo-PCU-8,11-dione) was performed by using an excess amount of m-chloroperbenzoic acid (3 equivalents) and resulted in the formation of the corresponding monolactone. The reaction would not proceed to the dilactone stage. The structure of the reaction product was established unequivocally via single crystal X-ray diffraction. Baeyer-Villiger oxidation of 1,9-dibromo-PCU-8,11-dione using ceric a… more
Date: May 2004
Creator: Akinola, Adeniyi O.
Item Type: Refine your search to only Thesis or Dissertation

Preparation and characterization of praseodymium oxide films and powders.

Description: Nanocrystalline praseodymium oxide films have been successfully generated on stainless steel substrates. The electrochemical deposition was performed in the cathode compartment of a divided electrochemical cell with a regular three-electrode configuration. The green films obtained by electrodeposition were then annealed at high temperatures for 1-3 hours. X-ray diffraction revealed the fluorite structure of Pr6O11 and the crystallite size was calculated. X-ray photoelectron spectroscopy was emp… more
Date: May 2004
Creator: Shang, Yajuan
Item Type: Refine your search to only Thesis or Dissertation

De novo prediction of the ground state structure of transition metal complexes.

Description: One of the main goals of computational methods is to identify reasonable geometries for target materials. Organometallic complexes have been investigated in this dissertation research, entailing a significant challenge based on transition metal diversity and the associated complexity of the ligands. A large variety of theoretical methods have been employed to determine ground state geometries of organometallic species. An impressive number of transition metals entailing diverse isomers (e.g., g… more
Date: December 2004
Creator: Buda, Corneliu
Item Type: Refine your search to only Thesis or Dissertation

An NMR Study of Trimethylsilylmethyllithium Aggregates and Mixed Trimethylsilylmethyllithium/Lithium trimethylsilylmethoxide Aggregates

Description: An NMR spectroscopy study of trimethylsilylmethyllilthium, TMSM-Li, indicates that TMSM-Li exists as two different aggregates in cyclopentane solution. Using previously reported colligative properties of TMSM-Li in different solutions in connection with new 13C and 6Li NMR data collected in this study, aggregation states were assigned as octamer and hexamer. Low temperature 13C and 6Li NMR peak intensities indicated an equilibrium exists between the two aggregates that shifts toward the octam… more
Date: December 2004
Creator: Medley, Marilyn S.
Item Type: Refine your search to only Thesis or Dissertation

An NMR Study of 2-Ethylbutyllithium/Lithium 2-Ethyl-1-butoxide Mixed Aggregates, Lithium Hydride/Lithium 2-Ethyl-1-butoxide Mixed Aggregates, n-Pentyllithium Aggregates, and n-Pentyllithium/Lithium n-Pentoxide Mixed Aggregates

Description: A 13C and 6Li variable temperature NMR study of 2-ethylbutyllithium/lithium 2-ethyl-1-butoxide mixed aggregates formed from reacting 2-ethyl-1-butanol with 2-ethylbutyllithium in two O/Li ratios of 0.2/1 and 0.8/1. The 0.2/1 sample resulted in two 2-ethylbutyllithium/lithium 2-ethyl-1-butoxide mixed aggregates and seven lithium hydride/lithium 2-ethyl-1-butoxide mixed aggregates. The lithium hydride mixed aggregates were also studied using selective 1H decoupling experiments. The 0.8/1 sampl… more
Date: December 2005
Creator: Sellers, Nicole
Item Type: Refine your search to only Thesis or Dissertation

Studies of spin alignment in ferrocenylsilane compounds and in regiospecific oxidation reactions of 1,9-dimethylpentacyclo [5.4.0.02,6.03,10.05,9]undecane-8,11-dione.

Description: Part I. The syntheses of a series of stable ferrocenylsilane compounds and their corresponding polyradical cations are reported. Electron spin properties of these molecules were investigated by cyclic voltammetry, ESR, and magnetic susceptibility measurements. All the compounds presented, showed significant electronic communication (>100 mV) between the redox centers by CV. Part II. Baeyer-Villiger oxidation of (1,9-dimethyl-PCU-8,11-dione) was performed using m-chloroperoxybenzoic acid i… more
Date: August 2006
Creator: Atim, Silvia
Item Type: Refine your search to only Thesis or Dissertation

Diphosphine Ligand Substitution in H4Ru4(CO)12: X-ray Diffraction Structures and Reactivity Studies of the Diphosphine Substituted Cluster Products

Description: The tetraruthenium cluster H4Ru4(CO)12 has been studied for its reactivity with the unsaturated diphosphine ligands (Z)-Ph2PCH=CHPPh2, 4,5-bis (diphenylphosphino)-4-cyclopenten-1,3-dione, bis(diphenyphosphino)benzene and 1,8- bis(diphenyl phosphino)naphthalene under thermal, near-UV photolysis, and Me3NO-assisted activation. All three cluster activation methods promote loss of CO and furnish the anticipated substitution products that possess a chelating diphosphine ligand. Clusters 1, 2, 3 and … more
Date: December 2006
Creator: Kandala, Srikanth
Item Type: Refine your search to only Thesis or Dissertation

Interfacial Electrochemistry of Metal Nanoparticles Formation on Diamond and Copper Electroplating on Ruthenium Surface

Description: An extremely facile and novel method called spontaneous deposition, to deposit noble metal nanoparticles on a most stable form of carbon (C) i.e. diamond is presented. Nanometer sized particles of such metals as platinum (Pt), palladium (Pd), gold (Au), copper (Cu) and silver (Ag) could be deposited on boron-doped (B-doped) polycrystalline diamond films grown on silicon (Si) substrates, by simply immersing the diamond/Si sample in hydrofluoric acid (HF) solution containing ions of the correspon… more
Date: May 2003
Creator: Arunagiri, Tiruchirapalli Natarajan
Item Type: Refine your search to only Thesis or Dissertation

Synthesis and Properties of Novel Cage-Annulated Crown Ethers

Description: Three cage-functionalized polyoxacrown ethers (9, 10 and 12) and four novel cage-functionalized polyoxamonoazacrown ethers (18, 20, 25 and 29) that contain 3,5-disubstituted-4-oxahexacyclo[5.4.0.02,6.03,10.05,9.08,11]dodecane ("oxahexacyclic") moiety have been synthesized and their respective alkali metal picrate extraction profiles along with that of three analogues 13, 14 and 21 have been obtained. The observed avidities and selectivities of the host molecules toward complexation and tra… more
Date: May 2003
Creator: Huang, Zilin
Item Type: Refine your search to only Thesis or Dissertation

Effects of Web-based Instruction in High School Chemistry.

Description: The intent of this study is to identify correlations that might exist between Web-based instruction and higher assessment scores in secondary education. The study framework was held within the confines of a public high school chemistry classroom. Within this population there were students identified as gifted and talented (GT) as well as those without this designation. These two classifications were examined for statistically higher assessment scores using a two-tailed t-test. Results indicated… more
Date: May 2003
Creator: Stratton, Eric W.
Item Type: Refine your search to only Thesis or Dissertation

Passivation effects of surface iodine layer on tantalum for the electroless copper deposition.

Description: The ability to passivate metallic surfaces under non-UHV conditions is not only of fundamental interests, but also of growing practical importance in catalysis and microelectronics. In this work, the passivation effect of a surface iodine layer on air-exposed Ta for the copper electroless deposition was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Although the passivation effect was seriously weakened by the prolonged air exposure, iodine passiv… more
Date: May 2004
Creator: Liu, Jian
Item Type: Refine your search to only Thesis or Dissertation

Electrodeposition of adherent copper film on unmodified tungsten.

Description: Adherent Cu films were electrodeposited onto polycrystalline W foils from purged solutions of 0.05 M CuSO4 in H2SO4 supporting electrolyte and 0.025 M CuCO3∙Cu(OH)2 in 0.32 M H3BO3 and corresponding HBF4 supporting electrolyte, both at pH = 1. Films were deposited under constant potential conditions at voltages between -0.6 V and -0.2 V vs Ag/AgCl. All films produced by pulses of 10 s duration were visible to the eye, copper colored, and survived a crude test called "the Scotch tape test", … more
Date: May 2004
Creator: Wang, Chen
Item Type: Refine your search to only Thesis or Dissertation

Modeling wild type and mutant glutathione synthetase.

Description: Glutathione syntethase (GS) is an enzyme that belongs to the ATP-grasp superfamily and catalyzes the second step in the biosynthesis of glutathione. GS has been purified and sequenced from a variety of biological sources; still, its exact mechanism is not fully understood. Four highly conserved residues were identified in the binding site of human GS. Additionally, the G-loop residues that close the active site during catalysis were found to be conserved. Since these residues are important for … more
Date: August 2004
Creator: Dinescu, Adriana
Item Type: Refine your search to only Thesis or Dissertation

Cu Electrodeposition on Ru with a Chemisorbed Iodine Surface Layer.

Description: An iodine surface layer has been prepared on Ru(poly) and Ru(0001) electrodes by exposure to iodine vapor in UHV and polarizing in a 0.1 M HClO4/0.005 M KI solution, respectively. A saturation coverage of I on a Ru(poly) electrode passivates the Ru surface against significant hydroxide, chemisorbed oxygen or oxide formation during exposure to water vapor over an electrochemical cell in a UHV-electrochemistry transfer system. Immersion of I-Ru(poly) results in greater hydroxide and chemisorbed o… more
Date: August 2005
Creator: Lei, Jipu
Item Type: Refine your search to only Thesis or Dissertation

The Revival of Electrochemistry: Electrochemical Deposition of Metals in Semiconductor Related Research

Description: Adherent Cu films were electrodeposited onto polycrystalline W foils from purged solutions of 0.05 M CuSO4 in H2SO4 supporting electrolyte and 0.025 M CuCO3∙Cu(OH)2 in 0.32 M H3BO3 and corresponding HBF4 supporting electrolyte, both at pH = 1. Films were deposited under constant potential conditions at voltages between -0.6 V and -0.2 V versus Ag/AgCl. All films produced by pulses of 10 s duration were visible to the eye, copper colored, and survived a crude test called "the Scotch tape test… more
Date: August 2005
Creator: Wang, Chen
Item Type: Refine your search to only Thesis or Dissertation

Synthesis and Complexation Studies of Novel Functionalized Crown Ethers and Azacrown Ethers

Description: Novel cage-functionalized azacrown ethers, i.e. 51, 52, 53, 55, 57, 61 and 62, which have various crown cavity and different number of nitrogen atoms incorporated, have been prepared. X-ray structures of 53, 55 and 57 have been obtained for the study of the crown topological structure. The complexation properties of crown 51, 52, 57, 61 and 62 have been evaluated via alkali metal picrate extraction, silver picrate extraction and ESI-MS study. The novel cage-fuctionalized azacrown ethers general… more
Date: May 2006
Creator: Huang, Zilin
Item Type: Refine your search to only Thesis or Dissertation

Interfacial Studies of Bimetallic Corrosion in Copper/Ruthenium Systems and Silicon Surface Modification with Organic and Organometallic Chemistry

Description: To form Cu interconnects, dual-damascene techniques like chemical mechanical planarization (CMP) and post-CMP became inevitable for removing the "overburden" Cu and for planarizing the wafer surface. During the CMP processing, Cu interconnects and barrier metal layers experience different electrochemical interactions depending on the slurry composition, pH, and ohmic contact with adjacent metal layers that would set corrosion process. Ruthenium as a replacement of existing diffusion barrier lay… more
Date: August 2006
Creator: Nalla, Praveen Reddy
Item Type: Refine your search to only Thesis or Dissertation
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