Chemistry Commons^™

Characterizing Dissolved Organic Matter And Cu2+, Zn2+, Ni2+, And Pb2+ Binding In Salt Water And Implications For Toxicity, Rachael L. Diamond

Theses and Dissertations (Comprehensive)

The binding of metal to dissolved organic matter in aquatic environments is important in controlling the bioavailability and potential toxicity of metals such as Zn²⁺, Pb²⁺, Ni²⁺ and Cu²⁺. The purpose of this research is to: (i) quantify binding capacity to different sources of marine organic matter at environmentally relevant concentrations; (ii) test fluorescence quenching and voltammetric method for use in seawater conditions and; (iii) compare predicted speciation parameters with toxicological observations in the same samples.

Information regarding the solubility of copper and copper compounds is important for risk assessment and can be …

Prevention Of Iron- And Copper-Mediated Oxidative Dna Damage By Neurotransmmitters And Related Compounds: Evidence For Metal Binding As An Antioxidant Mechanism, Carla Garcia

All Theses

An array of health concerns have been attributed to oxidative DNA damage from the hydroxyl radical (*OH), and the presence of the most biologically available metals iron and copper perpetuate the production of this radical through the Fenton and Fenton-like reactions, respectively. The concentrations at which flavonol and polyphenol antioxidants prevent 50% of DNA damage (IC50) were measured using gel electrophoresis assays upon Fe(II)/H2O2- and Cu(I)/H2O2-mediated DNA damage (Chapter 2). Results show that catechol- and gallol-containing antioxidants differ greatly in preventing DNA damage by Cu(I)/H2O2, compared to Fe(II)/H2O2, behavior that was explained using electron paramagnetic resonance spectroscopy. Semiquinone and other …

Supramolecular Organization Of Nanoparticles, Brenda M. Porta Linnell

Open Access Theses & Dissertations

The study of supramolecular structures with nano-architectures has become an active area of research in recent years. They have the potential to generate functional materials with applications in medicine and emerging technologies. In this dissertation, the supramolecular organization of gold nanoparticles (AuNP) and other nano-scale structures such as discrete styrene-based polymers was investigated. The synthesis and characterization of metal-mediated AuNPs systems using pendant ligands on the AuNP such as 11-diethylenetriamine-undecane-1-thiol, 11-Mercapto-undecanoic acid [2-(2-amino-ethylamino)-ethyl]-amide, Bis(11-oxo-nicotinic acid, undecine)disulfide, and 11-mercaptoundecanoic acid, and using Cu(II) to mediate the formation of supramolecular AuNP systems with sizes of 200 nm ¡V 3 fÃ?m, are …

Structural Studies Of Complex Compounds Of 6,6'-Diacetyl-2,2'-Bipyridine Dioxime With Copper(I/Ii), Platinum(Ii), And Palladium(Ii) Metal Ions, Abdurrahman Şengül, Hakan Ağaç, Burak Çoban, Erol Eroğlu

Turkish Journal of Chemistry

The tetradentate ligand 6,6'-diacetyl-2,2'-bipyridine dioxime (L) was obtained in high yield by the condensation reaction of 6,6'-diacetyl-2,2'-bipyridine with hydroxyl amine in alkaline solution. Density functional calculations and 3D modeling of the structure at the B3LYP/6-31G(d) level of theory for L revealed that the energy difference between the global trans conformer (trans-L), which possesses the C_{2h} point group, and the distorted cis conformer (cis-L) was 5.214 kcal/mol. Synthesis and characterization of the metal complexes with Cu(I), Cu(II), Pt(II), and Pd(II) metal ions were reported. L acted as a N_4-donor ligand to coordinate to the metal centers via N atoms of the …

Simultaneous Determination Of Copper And Cadmium In Environmental Water And Tea Samples By Adsorptive Stripping Voltammetry, Mohammad Bagher Gholivand, Alireza Pourhossein, Mohsen Shahlaei

Turkish Journal of Chemistry

A sensitive and selective method for the simultaneous determination of copper and cadmium in seawater, river water, and tea samples is described. The method is based on the adsorptive accumulation of 2,2--dithiosalicylic acid complexes of these elements onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. Optimal analytical conditions were as follows: ligand concentration of 11 nM, pH of 9.5, and an adsorption potential at --300 mV versus Ag/AgCl, with an accumulation time of 60 s. The peak currents are proportional to the concentration of copper and cadmium over the …

Guanidines, Amidines And Carbamides As Novel Sigma Receptor Ligands For Post-Stroke Therapeutics, Michelle Yolanda Cortes-Salva

USF Tampa Graduate Theses and Dissertations

Stroke is the 3^rd leading cause of death in the United States. For this reason, it has become our goal to find a drug that is capable of reestablishing intracellular and extracellular Ca⁺² flux upon direct binding to the sigma receptor, which can be delivered easily and efficiently. Our active research focuses the development of guanidine analogues that can serve as therapeutic drugs which target sigma 1 and sigma 2 receptors having a direct effect on Ca⁺² levels on the cell. The use of symmetrical guanidine analogues such as N,N'-di-o-tolyl guanidine (o-DTG) as therapeutic drugs for ischemic …

Preliminary Analysis Of Thermally Induced Condensed Phase Electron Transfer Reactions Of Copper Chloride With Electropositive Metals, Indrani Kothuru

Student Theses and Dissertations

The thermal stabilities and thermal decomposition of copper metal and its chlorides with electropositive metals such as Pb, Sn, Ni, Co, Cd, Fe, Cr and Mn at non standard temperatures was investigated. The heat capacities and change in enthalpy (ΔH) of the reactions were calculated using the onset temperatures obtained from DTA/TGA plot using Kirchhoff‟s Law. In the case of Co, it was observed that the calculated ΔH values at elevated temperatures gives a negative value indicating the reaction is exothermic but their respective DTA/TGA plots of CuCl2 + Co shows no sign of exothermic peak. However, in the case …

Theoretical And Experimental Studies In Nuclear Magnetic Resonance, Adrienne M. Roehrich

Department of Chemistry: Dissertations, Theses, and Student Research

Nuclear magnetic resonance (NMR) is a tool used to probe the physical and chemical environments of specific atoms in molecules. This research explored small molecule analogues to biological materials to determine NMR parameters using ab initio computations, comparing the results with solid-state NMR measurements. Models, such as dimethyl phosphate (DMP) for oligonucleotides or CuCl for the active site of the protein azurin, represented computationally unwieldy macromolecules. ³¹P chemical shielding tensors were calculated for DMP as a function of torsion angles, as well as for the phosphate salts, ammonium dihydrogen phosphate (ADHP), diammonium hydrogen phosphate, and magnesium dihydrogen phosphate. The …

A General Asymmetric Aldol Reaction Of Silyl Ketene Acetals Derived From Simple Esters To Aryl Alpha-Ketoesters, Brian Pagenkopf, Julie Le Engers

Chemistry Publications

No abstract provided.

Beta-Diketone And -Ketoenamine-Based Organic Building Blocks For Porous Metal Organic-Materials, Yoseph Solomon Marcos

LSU Doctoral Dissertations

This dissertation focuses on synthesis of multifunctional â-diketone and â-ketoenamine ligands and their reaction with metal ions, mainly Cu2+. Several new bi-, tri-, and tetrafunctional organosilicon â-diketone building blocks with â-diketone groups at approx. 109° (tetrahedral) were successfully synthesized. New thiophene based bifunctional ligands where the â-diketones are at about 145° are also reported here. We also prepared a range of new aryl-â-ketoenamines from their analogous â-diketones in very high yield using a simple microwave-assisted procedure. Reactions of organosilicon tris(â-diketone)s LH3 with Cu2+ were explored quite intensively. These ligands form metal-organic-polyhedra (MOPs) that are soluble in organic solvents, and insoluble …

A Study Of Growth And Breakdown Of Passive Film On Copper Surface By Electrochemical Impedance Spectroscopy, Amtul Naseer, Athar Yaseen Khan

Turkish Journal of Chemistry

Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry were used to investigate the oxide layer formed on a copper disc electrode and the changes that took place when treated potentiostatically in the range of -0.3 V to 0.9 V in aqueous buffer solution of pH 9.2. Equivalent circuits were used to model the response of the electrode, initially at equilibrium to an applied potential. These circuits were proposed for different potential ranges in order to illustrate the Cu/oxide/electrolyte system and its properties in terms of 2 interfaces. A criterion for the applicability of equivalent circuit models was discussed. Changes in the …

Doping Golden Buckyballs: Cu@Au16- And Cu@Au17- Cluster Anions, Lei-Ming Wang, Satya S. Bulusu, Hua-Jin Zhai, Xiao Cheng Zeng, Wang

Xiao Cheng Zeng Publications

The discovery of the unique catalytic effects of gold nanoparticles on oxide substrates[1] has stimulated a flurry of research into the structures and properties of free gold nanoclusters, which may hold the key to elucidating the catalytic mechanisms of supported gold clusters. One of the most remarkable results has been the discovery of planar gold cluster anions (Au_n^-) of up to twelve gold atoms and the 2D to 3D transition for clusters with n larger than 12.[2]– [4] Among larger gold clusters, Au₂₀ has been found to be a perfect tetrahedron.[5] A more recent study of …

Multifunctional Ligands For Supramolecular Chemistry, James Kakoullis

LSU Master's Theses

Metal-organic frameworks (MOFs) are the primary focus of the Maverick research group, almost exclusively with the acac moeity. Before such MOFs can be attempted, multifunctional ligands of the appropriate geometry for the desired MOFs first must be synthesized. In this thesis, the synthesis and characterization of two new β-diketone ligands, specifically, Re(CO)₃Cl(PyacH)₂, 2.2, Pphac₃H₃, 1.23, and its oxide 3.6, are described. Also in this thesis, attempts to synthesize other new MOFs will be discussed. The MOF for which Re(CO)₃Cl(PyacH)₂, 2.2 was designed was Re(CO)₃ClCu(pyac)₂] …

Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler

Chemistry Faculty Research

The effects of particle composition on heterogeneous catalysis were studied using dendrimer-encapsulated nanoparticles (DENs) as precursors to supported Pt-Cu catalysts. Bimetallic Pt-Cu DENs with varying Pt/Cu ratios were prepared in an anaerobic aqueous solution and deposited onto a high-purity commercial alumina support. The dendrimer template was then thermally removed to yield supported nanoparticle catalysts, which were studied with toluene hydrogenation and CO oxidation catalysis as well as infrared spectroscopy of adsorbed CO. Incorporating Cu into Pt nanoparticles had opposite effects on the two test reactions. Cu acted as a mild promoter for CO oxidation catalysis, and the promoting effect was …

Effects Of Sulfide Ions On The Inhibiting Efficiency Of Eda As A Copper Corrosion Inhibitor In Dilute Hcl Solution, Wen-Juan Qu, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

The anticorrosion action of EDA on copper in dilute HCl solution and the effect of sulfide ions on the inhibiting efficiency were studied by the Tafel plot method.The corrosion potential of Cu shifted to more positive value and the corrosion current density decreased after the addition of Na₂S to the solution.The results indicated that sulphide ions could increase the inhibiting efficiency of EDA because of the synergistic inhibition effect between EDA and Na₂S,resulting from the adsorption of HS^- on the surface of Cu,facilitated the adsorption of EDA to form a highly protective adsorbed layer which …

First- And Second-Derivative Spectrophotometry For Simultaneous Determination Of Copper And Cobalt By 1-(2-Pyridylazo)-2-Naphthol In Tween 80 Micellar Solutions, Habibollah Eskandari, Ali Ghanbari Saghseloo, Mansour Arab Chamjangali

Turkish Journal of Chemistry

1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous determination of copper and cobalt at trace levels. PAN at pH 1.89 forms red and green complexes with copper and cobalt, respectively, which are soluble in aqueous Tween 80 micellar media and are stable for at least 3 days. Under optimum conditions, calibration graphs were obtained for individual determination of copper and cobalt by zero- and first-derivative spectrophotometry and for simultaneous determination by first- and second-derivative spectrophotometry. Zero-crossing first-derivative spectrophotometry at 555 and 581 nm for cobalt and copper was used for the simultaneous determination, respectively. The second derivative method at 577 …

Copper Electrodeposition Under The Perturbation Of Hard Particles, Zeng-Wei Zhu, Di Zhu

Journal of Electrochemistry

Copper electrodepositon was carried out on the rotating cathode,with hard particles(such as ceramic beads) filling between the electrodes. The rotation of cathode led hard particles to polish and impact the surface of deposit during electrodeposition.Copper deposits with a mass of cuspidal nodules were produced in acid sulfate solutions while brittle deposits without nodules were produced in alkaline sulfate solutions. It was also found that brightening and smoothing deposit could be obtained from the alkaline solution, and the deposit was approximatively disordered orientation with granular morphology of about 100~300 nm. The results show that the polishing and impact of hard particles …

Determination Of Cadmium, Copper, Iron, Manganese, Lead And Zinc In Lichens And Botanic Samples By Electrothermal And Flame Atomic Absorption Spectrometry, Orhan Acar, Sümer Özvatan, Murat İli̇m

Turkish Journal of Chemistry

Within the framework of the International Atomic Energy Agency (IAEA) Analytical Quality Control Service (AQCS) Chemistry Unit a research program was initiated for the identification of trace elements such as Cd, Cu, Fe, Mn, Pb and Zn in IAEA lichen-338 for a proficiency test (PT). This was to evaluate the possibility of using lichens as biomonitors of trace elements in atmospheric pollution. Pyrolysis and atomization temperatures, atomization and background profiles, detection limits and characteristic masses of analytes in lichen samples with Ni, Ni + Pd and Ni + Pd + tartaric acid (TA) modifier mixture, and without any modifiers were …

Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Jian Qing Wang, Ngocnga Dao, Ham H. Kim, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

This work explores the thickness dependence of magneto-transport properties in granular thin films with different thickness. These results are compared with silver-based film series studied earlier. It was observed that the thickness dependence of the GMReffect was sensitive to the surface chemistry of the films. The extraordinary Hall effect (EHE) in these films was measured and found to be different from the Ag-based system. In the Cu-based system, the EHE is a weak function of film thickness over the range studied. When the variation of the spontaneous magnetization is taken into account the effective EHE has a universal thickness dependence

Electrodeposition Of Copper Into Trenches Under Rotating Hydrodynamic Condition, Jian-Jun Sun, Bu-Gao Xie, Wen-Hui Yin, Guo-Nan Chen

Journal of Electrochemistry

Silicon chips patterned with treneches were fixed onto a rotating electrode. Copper was electrodeposited into the trenches under rotating hydrodynamic conditions The sizes of the trenches are 1 m in height and 0.35 m, 0.50 m and 0.70 m in width, respectively. The effects of rotating of the chip, the current density and the concentration of Cu²⁺ on the filling of thetrenches were studied. It is found that lower current density and moderate concentration of Cu²⁺ resulted in a void free filling of the trenches.

Simultaneous Determination Of Copper, Zinc And Selenium In Chicken Liver By Differential Pulse Polarography, Güler Ekmekci̇, Güler Somer, Olcay Şendi̇l

Turkish Journal of Chemistry

A differential pulse polarographic method for the determination of copper, zinc and selenium in chicken liver is described. It was possible to determine these elements in a single sample solution after acid digestion. Dried liver samples weighing about 3 g were digested using HNO_{3} and HClO_{4} acids. Britton-Robinson or acetate buffer has been found suitable as the supporting electrolyte. For the determination of selenium, the hydrogen catalytic peak was used after the addition of molybdenum(VI) to the buffer solution at about pH 3. Then the pH of the same solution was increased to 4 and zinc was determined. For the …

Determination Of Manganese, Copper, Cadmium And Lead By Faas After Solid-Phase Extraction Of Their Phenylpiperazine Dithiocarbamate Complexes On Activated Carbon, Hasan Cesur

Turkish Journal of Chemistry

A solid-phase extraction method was developed for the pre-concentration of manganese, copper, cadmium and lead in water samples prior to their determination by flame atomic absorption spectrometry using phenylpiperazine dithiocarbamate as a new reagent. The optimum pre-concentration conditions have been investigated such as pH, volume of sample solution and the effects of some matrix elements. The obtained recovery was nearly 90 to 100, while the enrichment factor was 400 for metal spiked solutions.

Solid Phase Extraction Of Copper(Ii) By Modified Octadecyl Silica Membrane Disks With 3-{2-[2-(2-Hydroxyimino-1-Methyl-Propylideneamino)- Ethylamino]-Ethyl-Imino}-Butan-2-One~Oxime, Ömer Dalman, Serdar Karaböcek, Ahmet Demi̇rak, Mehmet Tüfekçi̇

Turkish Journal of Chemistry

A simple, selective and rapid method for determining trace amounts of copper(II) ions in various types of water samples using atomic absorption spectrophotometry was investigated. Copper(II) ions from water samples were preconcentrated by solid phase extraction using octadecyl silica membrane disks modified with 3-{2-[2-(2-hydroxyimino- 1-methyl-propylideneamino)-ethylamino]-ethyl-imino}-butan-2-one oxime, (H_{2}mdo). The experimental conditions were optimized by changing several parameters such as volume of eluting solvent, the effect of pH, eluent flow rates, the amount of H_2mdo, breakthrough the volume, limit of detection and maximum capacity of the disks for Cu^{2+} recovery. The method was applied to the recovery of Cu(II) ions from seven …

Effect Of Dissolved Oxygen On The Corrosion Behavior Of Coalesced Copper And Stainless Steel-206 In Acetic Solutions, Rong-Zong Hu, Xiong-Cao Zhao, Yu-Hua Weng, Chang-Jian Lin

Journal of Electrochemistry

Linear sweeping technique and dissolving oxygen sensor were used to study the effect of dissolved oxygen and relating factors on the corrosion behavior of coalesced copper and stainless steel-206 in acetic solutions. It was found: 1. The existing of dissolved oxygen is one of the important factors, which strongly influenced the corrosion behavior of coalesced copper and stainless steel-206 in acetic solution. 2. The existing of dissolved oxygen is benefitial to the preventing stainless steel-206 from corrosion in acetic solutions, but damage to the preventing coalesced copper from corrosion. 3. At the high temperature since the dissolved oxygen was escaping …

Polishing Rate And Dependent Factors Of Copper In Nh3 ·H2O Aqueous Solution Containing K3Fe(Cn)6 During Cmp, Han-Wei He, Yue-Hua Hu, Ke-Long Huang

Journal of Electrochemistry

Dependence of polishing rates of copper on concentrations of NH₃·H₂O, passivator K₃[Fe(CN)₆], γ-Al₂O₃ abrasives and polishing pressures, polishing rotative rates were studied. Dependent mechanisms were explained. It was shown a linear relation between polishing and polishing pressures and rotative rates within some range, non-linear relation between polishing and various reagent concentrations. Preston coefficient was varied. CMP recipe of the best polishing rate was gained: 4%K₃Fe(CN)₆+1%NH₃·H₂O+25%γ-Al₂O₃, K_p=0.02383. Technics conditions were 300 rpm and 80 kpa. The …

Magnetization Reversal Of Elliptical Co/Cu/Co Pseudo-Spin Valve Dots, Ngocnga Dao, Scott L. Whittenburg, Y. Hao, Leszek M. Malkinski, Jian Qing Wang, C. A. Ross

Chemistry and Biochemistry Faculty Publications

We present our recent simulated results on Cr (5 nm)/ Cu (5 nm)/ Co (5 nm)/ Cu (3 nm)/ Co (2 nm) pseudo-spin valve dots. The simulated results agree qualitatively with the experimental results. Three different sizes of elliptical dots, and were simulated. Our simulations show that in these types of dots magnetization reversal occurs by the formation of domain walls: for and for No domain wall was observed in the reversal of the dots. For such dots, the simulated loops show a small two-step reversal pattern with the thin upper layer partially reversing followed by complete reversal of both …

Determination Of Copper In The Waste Water Of Plating By Chronocoulometry For Flowing Solution, Xin-Hua Lin, Wei Chen

Journal of Electrochemistry

The chronocoulometry for flowing solution was devoloped and applied to the detemination of copper(Ⅱ) in the waste water of plating. The linear range of copper(Ⅱ) was 2～16mg/L, and the relative standard deviation was less than 0.1% (n =8). The recovery was 98%～103% for copper(Ⅱ) in the waste water.Chronocoulometry for flowing solution overcomed noise disturbance resulting from capacity current and variety of property of electrode surface. This method was sensitive,accurate and well reproducible.

Solid-Phase Extraction Of Copper With Lead 4-Benzylpiperidinedithiocarbamate On Microcrystalline Naphthalene And Its Spectrophotometric Determination, Hasan Cesur, Beki̇r Bati

Turkish Journal of Chemistry

Using lead 4-benzylpiperidinedithiocarbamate complex (Pb(4-BPDC)_{2}), a solid-phase extraction method was developed for pre-concentration and spectrophotometric determination of copper in water samples. In this method, copper in large volume liquid phase quantitatively replaces lead on colorless Pb(4-BPDC)_{2} complex and naphthalene solid phase mixture forming Cu-4-benzylpiperidinedithiocarbamate complex (Cu(4-BPDC)_{2}). The solid phase containing colored Cu(4-BPDC)_{2} is dissolved in chloroform and its absorbance is measured at 437 nm against the reagent blank. The range of linearity is 0.4 -10 \mu gml^{-1} of copper in chloroform, the molar absorptivity of the complex determined from the linear portion of Beer's law plot is 8.197x10^{3} lmol^{-1}cm^{-1} and …

Investigations Of Intramolecular Copper (I)-Arene Interactions Using A Ns2-Macrocyclic Ligand With Different Pendant Aryl Arms, Paul J. Lee

Honors Theses

Two macrocyclic ligands with a pendant phenyl group -N-[2-(l-phenyl)ethyl]-1-aza-4,8di thiacyclodecane (L1) and N-[2-0-phenyl)propyl]-1-aza-4,8-dithiacyclodecane, (L2) has been synthesized and characterized. The copper(I)-triphenylphosphine complex [LICu(PPhJ)]OTf , (2) was synthesized from L1 1/2(C6H6)[CuOTf]2, and PPh3. The complexes [LICu]OTf 1 and [L2Cu]OTf 3 were also synthesized and characterized using DC and IH NMR, UV-vis and lR spectroscopy, and ESI-MS. In CD2Cl2, 1 was found to have a fluxional behavior with the barrier ΔG to the process estimated at 9-11 kcal/mol. Variable temp. NMR spectroscopy of 1 gave compelling evidence that the phenylappended group is bound in an intramolecullar η2-fashion with the copper center. At …

Simultaneous Determination Of Gold(Ⅲ) And Copper(Ⅱ) With Two-Way Stripping Voltammetry, Rong-Zong Hu, Dong-Ping Wei, Guang Wei, Yue-Ying Liu

Journal of Electrochemistry

A novel Two-way Stripping Voltammetry method for simultaneous determination of Au³⁺ and Cu²⁺ was reported in this paper. Because of the strongly electrostatic attraction of carbon paste electrode towards Au(Ⅲ) ion at positive potential and the biochemical contribution of Gram-positive bacteria strain DO1, the ion can be determined by cathodic stripping voltammetry. At the same time, Cu(Ⅱ) is reduced readily under the catalysis of ultra-fine gold particles, thereafter it can be determined by anode stripping voltammetry. There is no interference between the determination of Au³⁺ and Cu²⁺ . A perfect liner relationship between the concentrations of …