Chemistry Commons^™

Substituent Effects And Mechanistic Insights On The Catalytic Activities Of (Tetraarylcyclopentadienone)Iron Carbonyl Compounds In Transfer Hydrogenations And Dehydrogenations, Bryn K. Werley, Xintong Hou, Evan P. Bertonazzi, Anthony Chianese, Timothy W. Funk

Chemistry Faculty Publications

(Cyclopentadienone)iron carbonyl compounds are catalytically active in carbonyl/imine reductions, alcohol oxidations, and borrowing hydrogen reactions, but the effect of cyclopentadienone electronics on their activity is not well established. A series of (tetraarylcyclopentadienone)iron tricarbonyl compounds with varied electron densities on the cyclopentadienone were prepared, and their activities in transfer hydrogenations and dehydrogenations were explored. Additionally, mechanistic studies, including kinetic isotope effect experiments and modifications to substrate electronics, were undertaken to gain insights into catalyst resting states and turnover-limiting steps of these reactions. As the cyclopentadienone electron density increased, both the transfer hydrogenation and dehydrogenation rates increased. A catalytically relevant, trimethylamine-ligated iron …

Modification Of Thermally Activated Delayed Fluorescence Emitters Comprising Acridan– Pyrimidine Moieties For Efficient Sky-Blue To Greenish-Blue Oleds, Yi-Zhen Li, Hsuan-Chi Liang, Chia-Hsun Chen, Ching-Huang Chiu, Bo-Yen Lin, Jake A. Tan, Jiun-Haw Lee, Tien-Lung Chiu, Man-Kit Leung

Chemistry Faculty Publications

Thermally activated delayed fluorescence (TADF) is a promising approach to harvest triplet excitons and achieve high-performance organic light-emitting diodes (OLEDs) for displays. In this study, we synthesized two new TADF emitters, 4Ac25CzPy and 4Ac35CzPy, featuring acridan–pyrimidine–carbazole moieties. Remarkably, a slight modification in the carbazole group position enables precise control of luminous color, resulting in emissions at 483 nm and 494 nm for 4Ac25CzPy and 4Ac35CzPy, respectively, in the electroluminescent device. Both compounds exhibit small energy difference between their singlet and triplet states (DEST) of 0.14 eV and 0.15 eV, confirming their TADF characteristics. Notably, OLEDs utilizing 4Ac35CzPy achieve outstanding performance …

The Impact Of Lead Corrosion Relating To The Contamination Of Drinking Water In Canada And In Indigenous Communities., Jessie A. Mcdonald

Corrosion Research

No abstract provided.

Modulation Of Electrocatalytic Activity By Tuning Anion Electronegativity: Case Study With Copper Chalcogenides, Harish Singh, David Prendergast, Manashi Nath

Chemistry Faculty Research & Creative Works

Anion-tuning in metallic chalcogenides has been shown to have a significant impact on their electrocatalytic ability for overall water splitting. In this article, copper-based chalcogenides (Cu2 X, X= O, S, Se, and Te) have been systematically studied to examine the effect of decreasing anion electronegativity and increasing covalency on the electrocatalytic performance. Among the copper chalcogenides, Cu2Te has the highest oxygen evolution reaction (OER) activity and can sustain high current density of 10 and 50 mA cm−2 for 12 h. The difference in intrinsic catalytic activity of these chalcogenide surfaces have been also probed through density functional theory calculations, which …

Asymmetric Electrode-Electrolyte Interfaces For High-Performance Rechargeable Lithium-Sulfur Batteries, Jia Chou, Ya-Hui Wang, Wen-Peng Wang, Sen Xin, Yu-Guo Guo

Journal of Electrochemistry

With a high cell-level specific energy and a low cost, lithium-sulfur (Li-S) battery has been intensively studied as one of the most promising candidates for competing the next-generation energy storage campaign. Currently, the practical use of Li-S battery is hindered by the rapidly declined storage performance during battery operation, as caused by irreversible loss of electroactive sulfide species at the cathode, dendrite formation at the anode and parasitic reactions at the electrode-electrolyte interface due to unfavorable cathode-anode crosstalk. In this perspective, we propose to stabilize the Li-S electrochemistry, and improve the storage performance of battery by designing asymmetric electrode-electrolyte interfaces …

Hydrophobicity Optimization Of Cathode Catalyst Layer For Proton Exchange Membrane Fuel Cell, Hao-Jie Chen, Mei-Hua Tang, Sheng-Li Chen

Journal of Electrochemistry

Hydrophobicity of the cathode catalyst layers (CCLs) crucially determines the performance of proton exchange membrane fuel cells (PEMFCs) by affecting the transports of oxygen and liquid water. In this regard, polytetrafluoroethylene (PTFE) is usually used as a hydrophobic additive to facilitate the oxygen and water transports in CCLs. So far, there remains lacking systematic effort to optimize the addition methods of PTFE in CCLs and the mechanisms behind. In this work, the effects of the approaches for PTFE addition and the distribution of PTFE on the mass transport of oxygen and the proton conduction in CCLs were studied by using …

Dependence Of Heat Transfer Model On The Structure Of Electrically Coil-Heated Microelectrodes, Ju Li, Sen Yang, Jian-Jun Sun

Journal of Electrochemistry

Electrically heated microelectrodes have gained much attention in electroanalytical chemistry in recent years. It has been shown that the promotion of mass transport and reaction kinetics at high-temperatures often results in increased current signals. However, there is no study about the heat transfer inner the microelectrodes which is necessary for the design and operation for microsensors. This report introduces a finite element software (COMSOL) to analyze the factors that influence the surface temperature (T_s), which is crucial for the heating ability of micro-disk electrodes with coils. Distances between the electrode surface and the bottom of the heated copper …

Antibacterial Testing On Silver/Zinc Oxide Nanoparticles/Organoclay Reinforced Chitosan Biocomposites, Lisna Junaeni Muiz, Ariadne Lakshmidevi Juwono, Zulkarnaen Paputungan, Yuni Krisyuningsih Krisnandi

Makara Journal of Science

Herein, bionanocomposites of chitosan (CS)/silver nanoparticle/organoclay/zinc oxide nanoparticle (CS/Ag/OC/ZnO) were prepared for antibacterial food packaging. This study examines the time variation in the AgNP synthesis method by comparing local (74˗85% deacetylated) and commercial chitosan (75%˗85% deacetylated) as a reducing and capping agent and seeks to reconstruct the optimum ratio formulations of AgNPs and ZnONPs in bionanocomposites for food packaging. The results reveal that the synthesis of AgNPs was successfully carried out using a local chitosan solution as a reducing and capping agent. The CS/Ag/OC/ZnO films exhibit structural, mechanical, and optical properties suitable for food packaging and antibacterial activity on Staphylococcus …

Development Of Single-Crystalline And 3d-Printable Porous Organic Materials, Mingshi Zhang

Dartmouth College Ph.D Dissertations

Porous organic materials with designable structures, large surface areas, low densities, and unique electronic and optical properties have found widespread applications in adsorption, separation, energy storage, and catalysis. However, the majority of organic porous materials are synthesized as fluffy powders, which poses two fundamental challenges for them. Firstly, they lack a single-crystal structure at the microscopic scale, making it difficult to study the specific pore size, shape, and potential substrate binding sites at the atomic level and further establish the structure-property relationship. Secondly, they lack the general processing method and macroscopic shape design, making it difficult to manufacture suitable components …

Solvatochromic And Aggregation-Induced Emission Active Nitrophenyl-Substituted Pyrrolidinone-Fused-1,2-Azaborine With A Pre-Twisted Molecular Geometry, Albert D. Campbell Jr., Kaia Ellis, Lyric K. Gordon, Janiyah E. Riley, Robert B. Hughley, Adeline M. Boswell, Ophelia Adjei-Sah, Prioska D. Baruah, Ra’Nya Malone, Carl Saint-Louis

Faculty Articles

Boron–nitrogen-containing heterocycles with extended conjugated π-systems such as polycyclic aromatic 1,2-azaborines, hold the fascination of organic chemists due to their unique optoelectronic properties. However, the majority of polycyclic aromatic 1,2-azaborines aggregate at high concentrations or in the solid-state, resulting in aggregation-caused quenching (ACQ) of emission. This practical limitation poses significant challenges for polycyclic aromatic 1,2-azaborines’ use in many applications. Additionally, only a few solvatochromic polycyclic aromatic 1,2-azaborines have been reported and they all display minimal solvatochromism. Therefore, the scope of available polycyclic 1,2-azaborines needs to be expanded to include those displaying fluorescence at high concentration and in the solid-state as …

Straight Out-Of-The-Tube: Analysis And Conservation Of George Mathieu’S Pour Une Aliénation Définitive Du Logos, Christy H. Mccutchen

Art Conservation Master's Projects

Pour une aliénation définitive du logos (96.5 cm × 195.6 cm, Buffalo AKG Art Museum, Acc.1971:7), painted in 1955 by French artist Georges Mathieu (1921-2012) is an iconic example of Lyrical Abstraction. Mathieu launched this European counterpart to Abstract Expressionism in the post-war upheaval of 1947. His unorthodox methods present a unique combination of aesthetic concerns and intrinsic material instability. Mathieu’s technique involved squeezing oil paints out-of-the-tube directly onto his canvas with rapid and spontaneous calligraphic motions. The primary condition issue for Pour une aliénation définitive du logos was the failing adhesion between this thickly applied paint and the primed …

Synthesis And Characterization Of Polymer-Based Complex Nanomaterials, Prashun G. Roy

Dissertations, Theses, and Capstone Projects

The original research work in this dissertation is about the use of polymers in two significantly important areas. One involves creating mesoporous silica materials with various morphologies using a mixed Pluronic surfactant system made up of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) surfactants, one of which contains long hydrophilic (PEO) blocks and the other has a significantly higher proportion of hydrophobic PPO . In addition, a glucose responsive core-shell type microgel was also developed for shifting the glucose responsive volume phase transition by using polymeric nanomaterials.

Chapter 1 of the dissertation discussed some historical background of synthesis and uses of …

Construction And Performance Optimization Of Bioconjugated Nanosensors For Early Detection Of Breast Cancer And Pro-Inflammatory Diseases, Pooja Gaikwad

Dissertations, Theses, and Capstone Projects

In recent years, nanosensors have emerged as a tool with strong potential in medical diagnostics. Single-walled carbon nanotube (SWCNT) based optical nanosensors have notably garnered interest due to the unique characteristics of their near-infrared fluorescence emission, including tissue transparency, photostability, and various chiralities with discrete absorption and fluorescence emission bands. Additionally, the optoelectronic properties of SWCNT are sensitive to the surrounding environment, which makes them suitable for in vitro and in vivo biosensing. Single-stranded (ss) DNA-wrapped SWCNTs have been reported as optical nanosensors for cancers and metabolic diseases. Breast cancer and cardiovascular diseases are the most common causes of death …

Synthesis And Evaluation Of Organic Additives For Copper Electroplating Of Interconnects, Yue-Hui Zhai, Yi-Xiao Peng, Yan Hong, Yuan-Ming Chen, Guo-Yun Zhou, Wei He, Peng-Ju Wang, Xian-Ming Chen, Chong Wang

Journal of Electrochemistry

Copper interconnects are essential to the functionality, performance, power efficiency, reliability, and fabrication yield of electronic devices. They are widely found in chips, packaging substrates and printed circuit boards, and are often produced by copper electroplating in an acidic aqueous solution. Organic additives play a decisive role in regulating copper deposition to fill microgrooves, and micro-vias to form fine lines and interlayer interconnects. Generally, an additive package consists of three components (brightener, suppressor, and leveler), which have a synergistic effect of super-filling on electroplating copper when the concentration ratio is appropriate. Many works of literature have discussed the mechanism of …

Effect Of Amine Additives On Thermal Runaway Inhibition Of Sic||Ncm811 Batteries, Bo-Wen Hou, Long He, Xu-Ning Feng, Wei-Feng Zhang, Li Wang, Xiang-Ming He

Journal of Electrochemistry

The high energy density of NCM batteries with high nickel content is a key advantage in replacing fossil fuels and promoting clean energy development, at the same time, is also a fundamental cause of serious safety hazards in batteries. Primary and secondary amines can lead to ring-opening polymerization of common ethylene carbonate electrolytes, resulting in an isolation layer between the cathode and the anode, and improving the thermal safety of the battery. In this work, the safety of batteries is considered both at the material level and at the cell level, based on the chemical reactions between amines and the …

Effects Of Traps On Photo-Induced Interfacial Charge Transfer Of Ag-Tio2: Photoelectrochemical, Electrochemical And Spectroscopic Characterizations, Zhi-Hao Liang, Jia-Zheng Wang, Dan Wang, Jian-Zhang Zhou, De-Yin Wu

Journal of Electrochemistry

In the field of metal-semiconductor composites based plasmon-mediated chemical reactions, a clear and in-depth understanding of charge transfer and recombination mechanisms is crucial for improving plasmonic photocatalytic efficiency. However, the plasmonic photocatalytic reactions at the solid-liquid interface of the electrochemical systems involve complex processes with multiple elementary steps, multiple time scales, and multiple controlling factors. Herein, the combination of photoelectrochemical and electrochemical as well as spectroscopic characterizations has been successfully used to study the effects of traps on the photo-induced interfacial charge transfer of silver-titanium dioxide (Ag-TiO₂). The results show that the increase of surface hydroxyl groups may …

Hydrodynamic Voltammetry Of Fe2+/3+ In Aqueous Deep Eutectic Solvents Towards Redox Flow Batteries, Desiree Mae Prado, Xiaochen Shen, Robert Savinell, Clemens Burda

Faculty Scholarship

Deep eutectic solvents (DESs) have recently attracted much attention as potential green electrolyte solvents for redox flow batteries. DESs are considered not only as environmentally sustainable but also economically attractive electrolytes because they can be resourced from biological feedstock (alcohols, urea, choline) and are earth-abundant and of low toxicity. Despite these advantages, DESs still have limitations in important aspects such as reactant and ion transport, which is inhibited due to hydrogen-bonding-induced viscosity. Thus, improving the transport properties of redox species in DESs is essential. In addition, we explore the quantitative addition of water to ethaline (a 1:2 choline chloride: ethylene …

Fabrication And Imaging Of Highly Ordered Plasmonic Au Nano-Prism And Self-Assembled Supramolecular Nanostructure, Ridwan Tobi Ayinla

Theses and Dissertations

The precise control of the resonance frequency of plasmonic nanostructures is critical and depends on the size, composition, shape, and dielectric nature of the environment. The ability to control the shape and size of nanomaterials acutely depends on the fabrication technique and material design. We used a cheap and scalable method known as nanosphere lithography (NSL) to fabricate plasmonic nano-prism (NP) on glass and indium tin oxide substrate (ITO). The methods involve substrate hydrophilicity treatment, polystyrene nanosphere masking, metal deposition, and mask removal. The array and specific morphology of the fabricated NP was established using scanning electron microscope (SEM) and …

Developing Strategies For The Integration Of Metal–Organic Frameworks (Mofs) Into E-Textiles For Chemical Sensing, Filtration, And Detoxification, Aileen Mary Eagleton

Dartmouth College Ph.D Dissertations

Metal-organic frameworks (MOFs) are crystalline porous materials that offer modularity through diverse combinations of metal nodes and linkers, as well as tailorable surface chemistry and structure, along with tunable conductivity. The integration of these framework materials onto fibers can result in robust and flexible MOF-based textiles with enhanced functionality and applicability. This thesis illustrates the versatility of multifunctional MOF-integrated textile systems, showcasing their unique properties and the advantages of installing MOFs at the fiber level.

Integrating Sensor Development, Risk Assessment, And Community Engagement To Support Environmental Justice In The Rural Community Of El Tiple, Colombia, David Bahamon Pinzon

All Dissertations

In Colombia, ethnic communities have traditionally been responsible stewards of natural resources. They recognize the importance of these resources for their livelihood, as well as their ancestral and cultural heritage. El Tiple, a rural Afro-Colombian community, has been affected by the incursion of private corporations that promoted the expansion of sugarcane monocrops in their territory. Since the introduction of the monoculture industry, local freshwater sources have been depleted due to intensive water use for irrigation of the sugarcane crops. Additionally, the intensive usage of agrochemicals has been linked with loss of native flora, damages to family farms, and pollution of …

Composite And Polymer Formulation Employing Sulfur And Bio-Olefin Feedstocks, Claudia V. Lopez

All Dissertations

Environmental sustainability represents a challenge for society since industrial growth has a direct impact on natural resources and waste production. New technologies that effectively incorporate waste into renewable resources are critical to the development of a sustainable and circular economy. The manufacturing of structural materials like Portland cement (OPC) is responsible for >8% of the global anthropogenic emissions of carbon dioxide, with ~ 1 kg of CO₂ released to the atmosphere for every kilogram of OPC produced. For instance, the development of sustainable structural materials is a key factor to reduce the greenhouse emissions and to attenuate the climate …

Leveraging Non-Covalent Interactions Between Small Organic Molecules And Inorganic Scaffolds In The Design Of Advanced Materials, Jonathan Lefton

Chemistry Theses and Dissertations

Powder diffraction is a powerful tool for studying crystal structures, especially as it relates to interactions of small organic molecules with inorganic compounds. The first part of this dissertation involves small organic ligands interacting with metal-organic framework, MOF-74. The first and simplest iteration involves the crystal structure solution of a neat, liquid loading of n-propylmercaptan to the open metal sites within the MOF-74 pores. Later studies investigate the leveraging of a similarly sized bitopic ligand in the solution loading of 1,2-ethanedithiol, which results in the amorphization of MOF-74. Having no crystallinity, amorphous or severely defected materials can be a …

Recent Progress Of Bifunctional Electrocatalysts For Oxygen Electrodes In Unitized Regenerative Fuel Cells, Tian-Long Zheng, Ming-Yu Ou, Song Xu, Xin-Biao Mao, Shi-Yi Wang, Qing-Gang He

Journal of Electrochemistry

Unitized regenerative fuel cells (URFCs), which oxidize hydrogen to water to generate electrical power under thefuel cells (FCs) mode and electrolyze water to hydrogen under the water electrolysis (WE) mode for recycling, areknown as clean and sustainable energy conversion devices. In contrast to the hydrogen oxidation reaction (HOR) andhydrogen evolution reaction (HER) on the hydrogen electrode side, the sluggish kinetics of oxygen reduction reaction(ORR) and oxygen evolution reaction (OER) on the oxygen electrode side requires highly efficient bifunctional oxygencatalysts. Conventional precious metal oxygen catalysts combine Pt and IrO₂ with excellent ORR and OER activities toachieve bifunctional electrocatalysis performance, but …

Ultramicroelectrode Experiments: Principles, Fabrications And Voltmmetric Behaviors, Zhen Ma, Jia-Yang Lin, Wen-Jing Nan, Lian-Huan Han, Dong-Ping Zhan

Journal of Electrochemistry

Due to the small size at least in one dimension (< 25 μm), ultramicroelectrode (UME) has small electric-double-layer capacitance, low IR drop, rapid mass transfer rate, fast response, high signal/noise ratio and high spatiotenporal resolution. UME is qualified not only to study the kinetics of fast electrode processes, but also to act as the probe of scanning electrochemical microscopies to obtain the localized chemical or electrochemical reactivity of the substrates. Thus, UMEs play a significant role in various research domains of electrochemistry, and have become an important electrochemical experimental method. Herein, we will introduce the basic principles, a simple fabrication method and voltammetric experimental protocols of UME, providing a guide to carry out the UME experiments.

Band Alignments Of Metal/Oxides-Water Interfaces Using Ab Initio Molecular Dynamics, Yong-Bin Zhuang, Jun Cheng

Journal of Electrochemistry

Band alignments of electrode-water interfaces are of crucial importance for understanding electrochemical interfaces. In the scenario of electrocatalysis, applied potentials are equivalent to the Fermi levels of metals in the electrochemical cells; in the scenario of photo(electro)catalysis, semiconducting oxides under illumination have chemical reactivities toward redox reactions if the redox potentials of the reactions straddle the conduction band minimums (CBMs) or valence band maximums (VBMs) of the oxides. Computational band alignments allow us to obtain the Fermi level of metals, as well as the CBM and VBM of semiconducting oxides with respect to reference electrodes. In this tutorial, we describe …

Electrochemical Scanning Tunneling Microscopy: Taking The Initial Stage Of Cu Electrodeposition On Au(111) As An Example, Zhuo Tan, Kai-Xuan Li, Bing-Wei Mao, Jia-Wei Yan

Journal of Electrochemistry

Electrochemical scanning tunneling microscopy (ECSTM) plays an important role in the field of electrochemistry, which can obtain potential-dependent structural information of electrode surface with high spatial resolution and observe some reaction processes in electrolyte solutions, and provide a powerful way to understand the interfacial structure and electrode processes from the perspective of high spatial resolution. In this article, the study of electrodeposition of Cu on Au (111) by ECSTM is taken as an example to introduce the experimental methods required for ECSTM and share our experience with other electrochemical groups. Firstly, the working principle of STM is introduced so that …

From Waste To Energy: The Electrochemical Reduction Of Co2 Using Recycled Nanostructured Catalysts, Ibrahim Badawy

Theses and Dissertations

The reduction of carbon dioxide (CO₂RR) using electrochemistry is a promising solution for the burgeoning global energy crisis. The overall vision of its implementation relies on renewable energy sources to power the reaction creating carbon neutral products and effectively closing the carbon cycle. Research in this field has come a long way since its inception in the mid-1900s. However, there remain significant hurdles and important considerations to overcome in order to reach full commercialization. Most electrocatalysts tested for CO₂RR have been designed solely for maximum performance while ignoring the environmental consequences if such a material were …

The Effect Of Heat Treatment And Chemical Treatment On Natural Fibre To The Durability Of Wood Plastic Composites – A Review, Nuratiqah Asyiqin Mohd Nasharudin, Nur Fatihah Sulaiman, Nurul Aziemah Mohammad, Wan Nor Raihan Wan Jaafar, Falah Abu Dr., Siti Norasmah Surip

Journal of Materials Exploration and Findings

The application of WPC is not only limited to indoor applications but has been extended to exterior applications where properties of WPC could compromise during service life. WPC was derived from wood fiber of various sizes to reinforce polymers. Wood fiber has the advantage of a cheaper price, being abundantly available, and ease of processing, however, the critical factor is its hydrophilic nature, where moisture absorption is likely to occur. Thus, treatments for reducing the hydrophilicity of wood fibers are applied. By treatment of wood fiber, the surface impurities were removed, leaving the roughened surface of fibers, thus providing a …

Clear As Glass: Novel Antibiotic Glasses Vitrified From Solution, Claire Lamberti

Chemistry Theses and Dissertations

The World Health Organization (W.H.O.) has maintained a list of essential medicines since 1977 (1). This list contains the medications considered to be the most effective and of the utmost importance to the needs of worldwide healthcare systems. If new forms of these drugs can be created, they can be studied for potential stability and transportation purposes, as well as drug delivery mechanisms. There are strategies to try and improve the physicochemical properties including forming polymorphs, salts, cocrystals, and amorphous formulations. There are issues with these techniques, and a large one is that in most cases the crystal structures of …

Preface To The Special Issue On Interfactial Regulation And Electrochemical Sensors, Jing-Hong Li, Yang Tian, Yuan-Hong Xu, Li-Min Zhang

Journal of Electrochemistry

No abstract provided.