Chemistry Commons^™

Study On Weak Alkaline Cyanide-Free Silver Plating Process For Etching Lead Frame, Jian-Wei Zhao, Hai-Feng Zhu, Xiao-Hui Yu, Gui-Yun Yuan, Zhi Sun

Journal of Electrochemistry

As a new development direction of integrated circuit chip carrier, etched lead frame has been gradually applied in microelectronics industry in recent years. Since the preparation of the etched lead frame requires the use of multiple layers of non-alkali-resistant photoresist films with specific patterns, and the traditional cyanide silver plating is unable to meet this requirement, making that the development of weakly alkaline cyanide free silver plating process has great significance. In this paper, a weak alkaline silver plating process based on 5,5-dimethylhydantoin (DMH) cyanide-free silver plating system was studied. The electrodeposition behavior of the system and the nucleation mechanism …

Effect Of Sodium Alcohol Thiyl Propane Sulfonate On Electrolysis Of High Performance Copper Foil For Lithium Ion Batteries, Sen Yang, Wen-Chang Wang, Ran Zhang, Shui-Ping Qin, Min-Xian Wu, Naotoshi Mitsuzaki, Zhi-Dong Chen

Journal of Electrochemistry

Electrolytic copper foils have been widely used in printed circuit boards and lithium-ion batteries due to their simple production process and high economic value. In the process of electrolysis foil making, additives can greatly improve the performance of electrolytic copper foils. In this work, the copper foils were prepared in a self-designed plate electrodeposition device of which the operating principles were in accordance with those of actual industrial production. A series of the Virgin Make-up Solution (VMS: 312.5 g·L^-1 CuSO₄·5H₂O, 100 g·L^-1 H₂SO₄, 50 mg·L^-1 Cl^-) containing …

Microstructure Of Electrodeposited Copper Foil: Discussion On The Mechanism Model Of Three-Dimensional Electrocrystallization, Ren-Zhi Liu, Ping-Ling Xie, Chong Wang

Journal of Electrochemistry

The manufacturing of electrolytic copper foil has attracted more and more attention with the extensive applications of printed circuit board and lithium battery. The industrial scale is still extending. Compared with the developments of electroplating equipment and electroplating process, there is limited research on the mechanism of electrodeposition. This paper summarizes the manufacturing process of electrodeposited copper foil and analyzes the differences of various electroplating parameters in different electrodeposited copper technologies, and points out the important role of electrodeposition current density in the formation of copper foil. By showing and comparing the microstructures of different electrodeposited copper foils, the influences …

Ultrasmall Nanodiamonds: Perspectives And Questions, Shery L.Y. Chang, Philipp Reineck, Anke Krueger, Vadym Mochalin

Chemistry Faculty Research & Creative Works

Nanodiamonds are at the heart of a plethora of emerging applications in areas ranging from nanocomposites and tribology to nanomedicine and quantum sensing. The development of alternative synthesis methods, a better understanding, and the availability of ultrasmall nanodiamonds of less than 3 nm size with a precisely engineered composition, including the particle surface and atomic defects in the diamond crystal lattice, would mark a leap forward for many existing and future applications. Yet today, we are unable to accurately control nanodiamond composition at the atomic scale, nor can we reliably create and isolate particles in this size range. In this …

Asymmetrical Spectral Continuum Between Anti-Stokes And Stokes Scattering Revealed In Low-Frequency Surface-Enhanced Raman Spectroscopy, Shuo Sun, Dhanusha T.N. Rathnayake, Yinsheng Guo

Department of Chemistry: Faculty Publications

An asymmetrical spectral continuum is observed in low-frequency surface-enhanced Raman spectroscopy (LF-SERS) in the terahertz (THz) region. This background continuum appears as a flat baseline in the Stokes side and a slope in the anti-Stokes side. Analysis shows this asymmetry originates from the different scaling of anti-Stokes and Stokes scattering with respect to the Bose−Einstein distribution. Such asymmetry is readily visible, under room temperature, in the low-frequency THz spectral range. Accounting for this spectral intensity asymmetry reveals the intrinsic continuum background of electronic origin, differing from local normal modes and collective relaxational motions. We also describe a numerical method, independent …

On The Exact Helium Wave Function Expansion, Carl W. David

Chemistry Education Materials

A ¹S wave function’s expansion for 2 electron atoms and ions is obtained and the leading coefficients are reported.

Polychlorinated Organic Contaminants In Baleen From North Pacific Ocean Whales, Briana R. Coulter

All HCAS Student Capstones, Theses, and Dissertations

Persistent organic pollutants (POP) have been detected and analyzed in various baleen whale tissues (blubber, muscles, liver, etc.) This study concentrated on detecting 7 polychlorinated biphenyls (PCB) and 14 organochlorine pesticides from baleen, a baleen whale tissue never before analyzed for POPs. These data were used to investigate temporal and geographic trends by sampling at every 1 cm interval along the length of the baleen plate. Four species of baleen whales stranded in the North Pacific Ocean were included in this study: gray (n=2), humpback (n=2), minke (n=1), and blue (n=1) whales. Organic contaminant concentrations were analyzed with respect to …

Site-Directed Mutagenesis Of Serine-72 Reveals The Location Of The Fructose 6-Phosphate Regulatory Site Of The Agrobacterium Tumefaciensadp-Glucose Pyrophosphorylase, Mashael Alghamdi Dr., Rania Ali Z Hussien, Yuanzhang Zheng, Hiral Patel, Matias D. Asencion Diez, Alberto A. Iglesias, Dali Liu, Miguel A. Ballicora

Chemistry: Faculty Publications and Other Works

The allosteric regulation of ADP–glucose pyrophosphorylase is critical for the biosynthesis of glycogen in bacteria and starch in plants. The enzyme from Agrobacterium tumefaciens is activated by fructose 6-phosphate (Fru6P) and pyruvate (Pyr). The Pyr site has been recently found, but the site where Fru6P binds has remained unknown. We hypothesize that a sulfate ion previously found in the crystal structure reveals a part of the regulatory site mimicking the presence of the phosphoryl moiety of the activator Fru6P. Ser72 interacts with this sulfate ion and, if the hypothesis is correct, Ser72 would affect the interaction with Fru6P and activation …

Carbon Nanotube Encapsulated Metal Selenide Nanostructures For Efficient Electrocatalytic Oxygen Evolution Reaction, Harish Singh, Wipula P.R. Liyanage, Manashi Nath

Chemistry Faculty Research & Creative Works

Nickel selenide nanowires were grown inside carbon nanotubes through in situ encapsulation via one-step chemical vapor deposition. These NiSe₂@CNT nanohybrids showed excellent electrocatalytic activity for water splitting with a low overpotential of 260 mV at 10 mA cm⁻², high current density, and extended stability owing to the synergistic effect between NiSe₂ and CNTs.

Multifunctional Nanomaterials For Energy Applications, Simas Rackauskas, Federico Cesano, Mohammed Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

No abstract provided.

Improved Performance Of Silica-Supported La0.5Ba0.5Feo3 In The Reverse Water Gas Shift - Chemical Looping Process For Carbon Dioxide Reduction – A Density Functional Theory Study, Jiawei Guo

USF Tampa Graduate Theses and Dissertations

Global warming is increasingly obvious, and the reduction of greenhouse gases is an effective way to heal. Increasing the efficiency of catalysts that is applied in the industry can significantly reduce the emission of greenhouse gases. Reverse water gas shift chemical looping (RWGS-CL) is a promising reaction to convert CO2 to CO. La0.5Ba0.5FeO3 (LBF) is a good candidate for RWGS-CL, which shows increased conversion yield when supported on silica. This research focuses on identifying the mechanism of RWGS-CL via silica-supported LBF by exploring the oxygen vacancy formation energy (EO-vac). Density Functional Theory (DFT) is a powerful computational method to solve …

Temperature-Resolved Surface Infrared Spectroscopy Of Co On Rh(111) And (2 × 1)-O/Rh(111), Elizabeth A. Jamka, Maxwell Z. Gillum, Christina N. Grytsyshyn-Giger, Faith J. Lewis, Daniel Killelea

Chemistry: Faculty Publications and Other Works

Heterogeneously catalyzed reactions over transition metal surfaces are pillars of chemical industry and account for a significant fraction of the global energy demand. CO oxidation provides insight into the relative reactivity of various oxygenaceous surface phases, and it is necessary to first understand where it binds to the surface and the nature of the local environment to develop robust mechanistic pictures of the reaction. Surface IR spectroscopy is a quantitative technique that also provides information about the binding sites and chemical environments of the adsorbed CO molecules. Here, we report results from a study of CO sticking to clean Rh(111) …

Examining Metal Contents In Primary And Secondhand Aerosols Released By Electronic Cigarettes, Kashala Fabrice Kapiamba, Weixing Hao, Stephen Adom, Wenyan Liu, Yue-Wern Huang, Yang Wang

Chemistry Faculty Research & Creative Works

The usage of electronic cigarettes (ECs) has surged since their invention two decades ago. However, to date, the health effects of EC aerosol exposure are still not well understood because of insufficient data on the chemical composition of EC aerosols and the corresponding evidence of health risks upon exposure. Herein, we quantified the metals in primary and secondhand aerosols generated by three brands of ECs. By combining aerosol filter sampling and inductively coupled plasma mass spectrometry (ICP-MS), we assessed the mass of metals as a function of EC flavoring, nicotine concentration, device power, puff duration, and aging of the devices. …

Exploring Structure-Function Relationship In Small-Molecular Catalysts Using Computational And Experimental Methodologies, Avik Bhattacharjee

Dissertations and Theses

Molecular modeling is a useful tool in the field of catalyst design for various processes. The use of Density Functional Theory (DFT) is routine in almost every discipline of chemistry. This allows for a deeper understanding of a molecular system even in situations where implementation of an experimental technique is unfeasible. However, without the right choice of theory and insufficient description, the model becomes susceptible to produce ambiguous results. This often leads to poor correlation with experimental findings hence an incomplete understanding of the system under study. Hence, to acquire a thorough knowledge of the intricacies involved in a system, …

Chiral Recognition Of Hydantoin Derivatives Enabled By Tetraaza Macrocyclic Chiral Solvating Agents Using 1H Nmr Spectroscopy, Jie Wen, Lei Feng, Hongmei Zhao, Li Zheng, Pericles Stavropoulos, Lin Ai, Jiaxin Zhang

Chemistry Faculty Research & Creative Works

Enantiomers of a series of hydantoin derivatives were prepared from d- and l-amino acids with p-tolyl isocyanate and 3,5-bis(trifluoromethyl)phenyl isocyanate as guests for chiral recognition by ¹H NMR spectroscopy. Meanwhile, several tetraaza macrocyclic compounds were synthesized as chiral solvating agents from d-phenylalanine and (1S,2S)-(+)-1,2-diaminocyclohexane. An uncommon enantiomeric discrimination has been successfully established for hydantoin derivatives, representatives of five-membered N,N-heterocycles, in the presence of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1a-1c by means of ¹H NMR spectroscopy. Several unprecedented nonequivalent chemical shifts (up to 1.309 ppm) were observed in the split ¹H NMR spectra. To evaluate practical applications …

A Multi‑Analytical Approach To Identify Red Colorants On Woodblock Prints Attributed To Suzuki Harunobu, Lyndsay Nichole Kissell, Trine K. Quady, Dario Durastanti, Samantha Springer, Jeannie Kenmotsu, Tami Lasseter Clare

Chemistry Faculty Publications and Presentations

Red organic dye identification is an important topic for conservation of Japanese ukiyo-e prints. Of particular interest are the works of Suzuki Harunobu, who was working at the inception of full-color printmaking. These prints were made on thin kōzo paper and woodblock printed with semi-transparent to opaque regions of dye(s) and/ or pigment(s) mixed with binder. This study used imaging analysis, X-ray fluorescence (XRF), Raman, and surfaceenhanced Raman spectroscopies (SERS) to identify the red dyes and pigments on Harunobu prints in the collection of the Portland Art Museum. Through image analysis (visible, UV, and IR illuminations), 23 prints were categorized …

Luminescence And Scintillation In The Niobium Doped Oxyfluoride Rb4Ge5O9F6:Nb, Darren Carone, Vladislav V. Klepov, Scott T. Misture, Joseph C. Schaeperkoetter, Luiz G. Jacobsohn, Mina Aziziha, Juliano Schorne-Pinto, Stuart A. J. Thomson, Adrian T. Hines, Theodore M. Besmann, Hans Conrad Zur Loye

Faculty Publications

A new niobium-doped inorganic scintillating oxyfluoride, Rb₄Ge₅O₉F₆:Nb, was synthesized in single crystal form by high-temperature flux growth. The host structure, Rb₄Ge₅O₉F₆, crystallizes in the orthorhombic space group Pbcn with lattice parameters a = 6.98430(10) Å, b = 11.7265(2) Å, and c = 19.2732(3) Å, consisting of germanium oxyfluoride layers made up of Ge₃O₉ units connected by GeO₃F₃ octahedra. In its pure form, Rb₄Ge₅O₉F₆ shows neither luminescence nor scintillation but when doped …

Characterization Of Competing Halogen- And Hydrogen-Bonding Motifs In Simple Mixed Dimers Of Hcn And Hx (X = F, Cl, Br, And I), Morgan A. Perkins, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

This work performs the first systematic comparison of hydrogen- and halogen-bonded configurations of the HCN/HX mixed dimer, where X = F, Cl, Br, and I. Eleven different minima have been characterized for these four heterogeneous dimers near the CCSD(T) complete basis set (CBS) limit. For each complex, two different hydrogen-bonded minima were identified: the global minimum where HX acts as the hydrogen bond donor and a local minimum where HX acts as the hydrogen bond acceptor. A halogen-bonded local minimum was also identified for all but the fluorine mixed dimer. To the best of our knowledge, three of the minima …

Enhancing Vanadium Redox Battery Performance Using Tungsten-Bismuth-Based Oxide Nanostructures As Electrode Modifiers, Taher Al Najjar

Theses and Dissertations

Renewable energy power plants require high efficiency conversion and storage systems that can store high amounts of energy and can be integrated with the electrical grid. Vanadium redox flow batteries are very promising for this application. However, one major drawback of VRFBs is their low power density which means that right now they cannot replace non-renewable energy sources. Different carbon materials are used as electrodes in VRFBs and each carbon material affects the battery’s performance in a different way. Modification of these electrodes can increase the power density of the battery. Some metal oxides like tungsten oxide can enhance vanadium …

Managing Risk And Knowledge: Frameworks To Guide Knowledge-Enabled Technology Transfer, Martin Lipa Dr, Anne Greene

Level 3

Technology transfer is not only about the transfer of technology, but also about the transfer of knowledge, as evidenced by definitions of KM within the biopharma industry and beyond. However, knowledge transfer is often not well structured and its effectiveness – in particular for tacit knowledge (i.e., know how) – is an opportunity for improvement which can lead to many benefits. This article profiles recent research into the topic of improving knowledge transfer during technology transfer and presents several recently developed frameworks for improving such. The article furthermore explains how the frameworks can be co-deployed in support of robust knowledge …

Grotthuss Molecular Dynamics Simulations For Modeling Proton Hopping In Electrosprayed Water Droplets., Lars Konermann, Scott Kim

Chemistry Publications

Excess protons in water exhibit unique transport properties because they can rapidly hop along H-bonded water wires. Considerable progress has been made in unraveling this Grotthuss diffusion mechanism using quantum mechanical-based computational techniques. Unfortunately, high computational cost tends to restrict those techniques to small systems and short times. Molecular dynamics (MD) simulations can be applied to much larger systems and longer time windows. However, standard MD methods do not permit the dissociation/formation of covalent bonds, such that Grotthuss diffusion cannot be captured. Here, we bridge this gap by combining atomistic MD simulations (using Gromacs and TIP4P/2005 water) with proton hopping. …

Stereocontrolled Access To Δ-Lactone-Fused-Γ-Lactams Bearing Angular Benzylic Quaternary Stereocenters, Timothy K. Beng, Morgan J. Rodriguez, Claire Borg

All Faculty Scholarship for the College of the Sciences

C-fused γ-lactam-lactones are resident in several bioactive molecules, including anticancer agents such as omuralide. In this embodiment, we report mild conditions for the catalytic halolactonization of lactam-tethered 5-aryl-4(E)-pentenoic acids. The use of dichloromethane as the solvent and Ph₃PS as the catalyst led to predominant 6-endo-trig cyclization and furnished the trans-fused-γ-lactam-δ-lactones. The transformation is modular, regioselective, chemoselective, and diastereoselective. The γ-lactam-δ-lactones bear angular quaternary benzylic stereocenters, which is noteworthy since the presence of a quaternary carbon in bioactive small molecules often promotes an element of conformational restriction that imparts potency, selectivity, and metabolic stability. The …

Preparation Of Carbon Aerogels From Polymer-Cross-Linked Xerogel Powders Without Supercritical Fluid Drying And Their Application In Highly Selective Co2adsorption, Rushi U. Soni, Vaibhav A. Edlabadkar, Daniel Greenan, Parwani M. Rewatkar, Nicholas Leventis, Chariklia Sotiriou-Leventis

Chemistry Faculty Research & Creative Works

Carbon aerogels are well-known materials for their high porosity and high surface areas. They are typically made from pyrolysis of carbonizable polymeric aerogels. Here, we report an alternative route to monolithic carbon aerogels starting from xerogel powders. Use of powders speeds up solvent exchanges along sol-gel processing, and xerogelling bypasses the supercritical fluid drying step that is needed for making polymeric aerogels. Overall, this alternative route results in time, energy, and materials efficiency in the fabrication of carbon aerogels. Specifically, polymer-cross-linked silica xerogel powders were prepared via free-radical surface-initiated polymerization of acrylonitrile (AN) on a suspension of silica particles derived …

Calcium Bistriflimide-Mediated Sulfur(Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, Nicholas D. Ball, O. Maduka Ogba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign …

Emerging Technologies: Empowering People To Capture, Share And Transfer Tacit Knowledge, Donncadh J. Nagle, Melanie J. Adams

Level 3

ICH Q10 was published in 2008, and presented a model for an effective Pharmaceutical Quality System (PQS). However, the industry still has some way to go in embracing and implementing its principles in order to achieve greater product realisation, to establish and maintain a state of control, and to facilitate continual improvement.

ICH Q10 introduced us to two key enablers: Knowledge Management (KM) and Quality Risk Management (QRM).^[1] While the pharmaceutical industry has made progress in implementing the principles of QRM since 2008, there has been significantly slower progress in implementing knowledge management practices. However, there may be solutions …

Calcium Bistriflimide-Mediated Sulfur (Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Nicholas Ball, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, O Maduka Ogba

Pomona Faculty Publications and Research

We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign …

Detection And Quantification Of Arsenic Pollution With A Moss Bio-Indicator And Icp-Ms, Erin R. Bowey

University Honors Theses

Heavy metal pollution is a recognized concern with an established source of anthropogenic activity, which is ever-increasing. While work has been done to make the monitoring of some metals more accessible, resourceful, and efficient with the use of epiphytic moss as a bio-indicator, this method has not been optimized for the detection of arsenic. Previously used analytical instrumentation has not proven sensitive enough to reliably detect arsenic, creating a gap in the monitoring process. However, inductively coupled plasma mass spectrometry (ICP-MS) is proposed as the solution to fill this gap. Its potential for low limits of detection and quantification express …

The Regulation Of Atg9a-Mediated Aggrephagy By An Ulk1-Independent Atg13-Atg101 Complex, Joshua Youngs

Undergraduate Honors Theses

Aggrephagy, a type of autophagy, is an essential cellular process by which protein aggregates are collected and broken down in the lysosome. Protein aggregates are implicated in several diseases including Alzheimer’s disease, diabetes, and cancer. Here, we investigate the ATG13-ATG101 protein complex, a sub-complex of the canonical ULK1 complex whose regulatory role in aggrephagy is not completely understood. We also develop a protein fragment complementation (PFC) assay using the biotin ligase TurboID to study the functions of the ATG13-ATG101 complex with increased specificity. We demonstrate that ATG13 is required for optimal degradation of p62-ubiquitin condensates. We also show that a …

Studies In The Use Of 1,1'-Di(1-Hydroxyethyl)Ferrocene As A Flame Retardant For Polyurethanes, Chanel Yeary

Electronic Theses & Dissertations

Significant research in non-toxic flame retardants (FR) has been performed in recent years since the dangerous consequences of halogenated FR were found. As early as the 1970’s, carcinogenic the side effects of halogenated compounds were being acknowledged. Since the early 2000’s halogenated FRs began being phased out of use due to these negative side effects. Since then, significant research has been exploring alternative effective flame retardants. Ferrocene (Fc) is a promising alternative to halogenated FRs due to its nontoxicity and FR properties. This research will report on the synthesis of 1,1’-di(1-hydoxyethyl) ferrocene (DHEFc) and its incorporation into a polyurethane. A …

Metabolomic Analysis, Identification And Antimicrobial Assay Of Two Mangrove Endophytes, Stephen Thompson

USF Tampa Graduate Theses and Dissertations

Natural products have played major roles in drug discovery and provided sources for many new drugs. Secondary metabolites, also called natural products, are organic compounds that are produced from fungi, bacteria, and other living organisms. Secondary metabolites produced by endophytic fungi include alkaloids, phenols, peptides, enzymes, polyketides, and terpenes. Endophytic fungi are rich sources of secondary metabolites and demonstrate bioactivity against many human pathogens including the ESKAPE pathogens. This thesis explores the diverse roles of endophytic fungi and their production of unique secondary metabolites for potential drug discovery and development. Secondary metabolites from two endophytic fungi (EG10-21E-2-HDAC & TAP14-34A-2-HDAC), collected …