Advanced Chemistry Research Articles

Identifying Opportunities to Promote Systems Thinking in Catalysis Education

While several engineering and science disciplines, including biology and environmental science, have greatly benefited from adopting a systems thinking approach, its extension to chemistry education is a much more recent advancement. The initial body of literature in this direction has largely surveyed the feasibility for systems thinking in general chemistry courses. Herein, we go a step further to explore the possibilities that systems thinking present for the instruction of more advanced chemistry courses, specifically in the context of catalysis education. Since catalysis has conventionally been taught employing a reductionist perspective, we identify the opportunities and challenges for instructors in transitioning to a systems thinking teaching style. We build our analysis in accordance with the principle of constructive alignment, where we systematically address the implications for systems thinking in writing intended learning outcomes, designing learning activities, and formulating student assessments. Through a series of carefully crafted examples in homogeneous as well as heterogeneous catalysis, we illustrate how embracing systems thinking can potentially enable a paradigm shift in catalysis education.

Teach What You Know Day: An Assignment to Bring Peer Learning into Upper Division Chemistry Courses

Peer learning has become a central feature in many postsecondary classrooms. Many peer learning activities feature near-peer instructors who had previously completed the course and who later serve as peer leaders. There are relatively few examples of activities in which students in a course act as true peer instructors for their classmates. One such activity is described herein. This activity, “Teach What You Know Day” (TWYKD), was implemented in an advanced organic chemistry course. Students in this course had varied background preparation and previous knowledge. Students capitalized on this knowledge to present course topics to their peers. During this activity, the peer leaders gave a lecture and helped their classmates work through practice problems. Assessment of this activity was conducted via a student perception survey and by comparing exam scores on TWYKD and non-TWYKD-related questions. The survey results indicate that the students generally had a positive reaction to this assignment. The exam assessment shows that students were able to learn from their peers. This assignment provides many benefits to students enrolled in upper division chemistry courses. With some personalization of the lecture topics, TWYKD would be a valuable addition to other upper division chemistry courses.

Technology development in thermochemistry materials

Thermochemistry is an important basic concept in studying advanced chemistry. Thermochemistry is very important to understand correctly and easily. This research aims to develop technology that can facilitate understanding of thermochemistry. This research is a research and development research (R & D). In this research, a technological development can be produced which can be used to facilitate understanding of thermochemical concepts. This research resulted in a framework of thermochemical material integrated with science (biology, physics), mathematics, engineering, ICT technology.

Undergrads hit hard by pandemic navigate disruptions

In spring 2020, biochemistry major Ariana Subhit was just beginning to delve into the trials and delights of advanced chemistry at Florida State University. As a second-year college student, she wa...

Closed-Loop Nanopatterning of Liquids with Dip-Pen Nanolithography.

The ability to reliably manipulate small quantities of liquids is the backbone of high-throughput chemistry, but the continual drive for miniaturization necessitates creativity in how nanoscale samples of liquids are handled. Here, we describe a closed-loop method for patterning liquid samples on pL to sub-fL scales using scanning probe lithography. Specifically, we employ tipless scanning probes and identify liquid properties that enable probe-sample transport that is readily tuned using probe withdrawal speed. Subsequently, we introduce a novel two-harmonic inertial sensing scheme for tracking the mass of liquid on the probe. Finally, this is combined with a fluid mechanics-based iterative control scheme that selects printing conditions to meet a target feature mass to enable closed-loop patterning with better than 1% accuracy and ∼4% precision in terms of mass. Taken together, these advances address a pervasive issue in scanning probe lithography, namely, real-time closed-loop control over patterning, and position scanning probe lithography of liquids as a candidate for the robust nanoscale manipulation of liquids for advanced high-throughput chemistry.

ChemElectroChem: Beyond Lithium‐Ion Batteries

Generations to come: Over the past decade, lithium-ion batteries have been widely applied. However, they still face great challenges to further improve their energy density and stability. Therefore, it is necessary to develop alternative energy-storage technologies with the potential for higher energy densities than those of lithium-ion batteries, that are so-called “beyond lithium-ion batteries”. The development of efficient energy-storage technologies is important to build a sustainable society. Over the past decade, lithium-ion batteries have been widely applied in electric vehicles, portable electronics, and household/grid-connected energy storage systems. However, lithium-ion batteries still face great challenges in further improving their energy density and stability. It is necessary to develop an alternative energy-storage technology that has the potential for higher energy densities than those of lithium-ion batteries, so-called “beyond lithium-ion batteries”. Some technologies “beyond lithium-ion batteries” are expected to exceed the theoretical limits of lithium-ion battery technology, including sodium/ potassium-ion batteries, lithium-sulfur batteries, metal-air batteries, supercapacitors, which are quickly being approached by cell manufacturers. As for sodium-/potassium-ion batteries, their advantage is that the reserves of potassium and sodium are abundant. However, sodium-/potassium-ion batteries have a relatively low potential, owing to the electrostatic repulsion, while the low melting point of sodium-/potassium-ion batteries may make them dangerous in the event of thermal runaway. For all-solid-state Li−S batteries, it is necessary to deeply understand the charge transport in the composite cathode. For metal-air batteries, the optimization of metal anodes and air electrodes with high utilization and excellent cyclability is key to improving their energy conversion efficiency and cycle life. Supercapacitors work in a different way compared with the batteries mentioned above. The challenge for current supercapacitor technology is to improve the energy density without sacrificing the power density and the cycle life. Therefore, these problems in energy-storage technologies beyond lithium-ion batteries need to be solved urgently. In this research topic, we have collected a series of valuable invited contributions regarding the second life battery use and other novel energy-storage technologies beyond Li-ion batteries. As the Guest Editors appointed by ChemElectroChem, we would like to thank all of the authors for their valuable contributions in this research topic, and all the reviewers for their important and thoughtful comments and insights. We hope that this Special Collection on Beyond Li–Ion Batteries will provide some useful insights for the future development of energy storage/conversion technologies, and inspire researchers to comprehend the advanced materials chemistry for energy-related applications. Yawen Tang received his BS degree and MS degree from Nanjing Normal University (China) in 1992 and 2002, respectively, and his PhD from Nanjing University of Science & Technology (China) in 2011. He is currently a professor at College of Chemistry and Materials Science at Nanjing Normal University (China). His main research interests are the synthesis and assembly of nanomaterials, and their applications in batteries, fuel cells, and photocatalysis. Jong-Min Lee received his Ph.D degree at Department of Chemical Engineering at Columbia University (USA) in 2003. He worked in the Chem. Sci. Division at Lawrence Berkeley National Laboratory (USA) and at the Department of Chemical Engineering in University of California at Berkeley (USA) as a postdoctoral fellow in 2006–2008. He is currently an associate professor in School of Chemical and Biomedical Engineering at Nanyang Technological University (Singapore). His research interests are electrochemistry, green chemistry, and nanotechnology. Gengtao Fu received his PhD degree at School of Chemistry and Materials Science at Nanjing Normal University (China) in 2017. He spent one year (2015–2016) as a visiting scholar at Materials Science and Engineering Program and Texas Materials Institute, University of Texas at Austin (USA). He worked at Nanyang Technological University (Singapore) under the supervision of Prof. Jong-Min Lee as a research fellow in 2017–2019. He currently works at the Materials Science and Engineering Program and Texas Materials Institute (USA) with Prof. John B. Goodenough, University of Texas at Austin (USA). His current research interests are in the areas of nanostructured electrocatalysts and their application in energy storage and conversion.

Examination of the method for detecting antifungal agents for citrus fruits by SERS method

All scientific disciplines require an amalgam of expertise from different fields to function. This is particularly necessary in biology where key techniques can be based on advanced chemistry, physics and engineering principles. This multidisciplinary aspect is often founded on the need to achieve precise measurements of biological compounds, image extremely small organisms and structures in high definition or separate different biological molecules from one another. All of these require accurate, precise and reliable techniques to carry out the task. One such technique is surface-enhanced Raman spectroscopy (SERS). SERS is complex but relies on Raman scattering – the phenomenon of photons being scattered by molecules – occurring with molecules that are adsorbed to a solid surface. The detection of this scattering allows for the identification of specific molecules, even in very low concentrations. This is invaluable in biology where active biomolecules (e.g. proteins) can be present in extremely low concentrations. Dr Hiroyuki Takei of the Graduate School of Life Sciences, Toyo University, Japan, is working on a project that is focused creating a SERS technique that can consistently and accurately detect fungicide levels on citrus fruits.

Synthesis of composite nanopowder through Mn doped ZnS-CdS systems and its structural, optical properties

The design of new functional materials is a driving force for the development of advanced materials chemistry. Out of many new-style substances, the fabrication of composite nanopowders possesses attracted considerable attention in industry and academia, as they often exhibit significant advancement in the effect of materials estimate to typical macro and micro combinations. The developed ZnS-CdS composite nanopowders with unique and tailored properties for various applications in the fields of surface-improved catalysis, photonic crystals, nano-electronic and LED appliances, etc. In practice, Mn2+ ions doped ZnS-CdS mixed nanopowders are held in the lead 2–6 bulk solid-state mixture by the control bandwidth of 3.7 and 2.4 eV for ZnS and CdS at room temperature. The present research deals with the preparation, structural and spectral characterizations of transition metal ions doped ZnS-CdS composite nanopowders. X-ray diffraction patterns indexed to the cubic crystalline phase of both ZnS and CdS and the average crystallite size is evaluated using Scherer's formula is in the class of nanometer-range. Morphological images of Mn2+ ions ZnS-CdS composite nanopowders are in unequal mode structure with agglomerated fragment with nano-size. The spectra of optical absorption and EPR reveal the distorted octahedral symmetry. By correlating optical and EPR data, the evaluated bonding parameters suggested that the bonding between the doped ions and ligands are partially covalent. The luminescent spectrum gives the emission bands in UV, blue, and green regions. The calculated CIE chromaticity coordinates from emission spectra give the color perception of the prepared nanocomposites. FTIR spectrum shows the essential oscillating function of ZnS, CdS plus additional active groups. Enhanced paramagnetic nature is observed at room temperature of the prepared material which is intrinsically caused by exchange coupling between the spin of the carriers and local magnetic moments.

Coulomb electron pairing in a tight-binding model of La-based cuprate superconductors

We study the properties of two electrons with Coulomb interactions in a tight-binding model of La-based cuprate superconductors. This tight-binding model is characterized by long-range hopping obtained previously by advanced quantum chemistry computations. We show analytically and numerically that the Coulomb repulsion leads to a formation of compact pairs propagating through the whole system. The mechanism of pair formation is related to the emergence of an effective narrow energy band for Coulomb electron pairs with conserved total pair energy and momentum. The dependence of the pair formation probability on an effective filling factor is obtained with a maximum around a filling factor of 20 (or 80) percent. The comparison with the case of the nearest neighbor tight-binding model shows that the long-range hopping provides an increase of the phase space volume with high pair formation probability. We conjecture that the Coulomb electron pairs discussed here may play a role in high temperature superconductivity.

Wstępne analizy wymagań balistycznych prochów LOVA do amunicji czołgowej nowej generacji

At the end of 2016, the Scientific-Industrial Consortium (Mesko S.A., Polska Grupa Zbrojeniowa S.A., Warsaw University of Technology, Military University of Technology, Military Institute of Armament Technology) set up an R&D project to develop and manufacture a demonstrator of new generation critical components for a 120 mm Polish tank munition. The critical elements for the project included a combustible charge case, an insensitive propellant and tungsten rods for subcalibre projectiles. The task of the Military University of Technology was to develop the basic technology and fabricate insensitive LOVA propellants on a laboratory scale (research team of the Faculty of Advanced Technologies and Chemistry) and carry out the ballistic and simulation tests of a 120 mm tank gun using ammunition incorporating the developed LOVA propellant (research team of the Faculty of Mechatronics, Armamen and Aerospace). The article also includes an analysis of available literature on energy and ballistic properties of LOVA and JA-2 propellants. Closed-vessel tests of JA-2 propellant (manufactured by Nitrochemie AG, designation LO5460) were also carried out. The tests were carried out in a 200 cm3 closed vessel. Based on the propellant gas pressure/time records, the propellant force and co-volume, and dynamic vivacity curves were determined. A linear combustion rate coefficient was determined using the measured results of the propellant grain geometry. The authors’ own data enabled the carrying out of preliminary simulation tests of the 120 mm propellant system.

Experimental and Theoretical Investigations of the Radical-Radical Reaction: N2H3 + NO2.

The N2H3 + NO2 reaction plays a key role during the early stages of hypergolic ignition between N2H4 and N2O4. Here for the first time, the reaction kinetics of N2H3 in excess NO2 was studied in 2.0 Torr of N2 and in the narrow temperature range 298-348 K in a pulsed photolysis flow-tube reactor coupled to a mass spectrometer. The temporal profile of the product, HONO, was determined by direct detection of the m/z +47 amu ion signal. For each chosen [NO2], the observed [HONO] trace was fitted to a biexponential kinetics expression, which yielded a value for the pseudo-first-order rate coefficient, k', for the reaction of N2H3 with NO2. The slope of the plot of k' versus [NO2] yielded a value for the observed bimolecular rate coefficient, kobs, which could be fitted to an Arrhenius expression of (2.36 ± 0.47) × 10-12 exp((520 ± 350)/T) cm3 molecule-1 s-1. The errors are 1σ and include estimated uncertainties in the NO2 concentration. The potential energy surface of N2H3 + NO2 was investigated by advanced ab initio quantum chemistry theories. It was found that the reaction occurs via a complex reaction mechanism, and all of the reaction channels have transition state energies below that of the entrance asymptote. The radical-radical addition forms the N2H3NO2 adducts, while roaming-mediated isomerization reactions yield the N2H3ONO isomers, which undergo rapid dissociation reactions to several sets of distinct products. The RRKM multiwell master equation simulations revealed that the major product channel involves the formation of trans-HONO and trans-N2H2 below 500 K and the formation of NO + NH2NHO above 500 K, which is nearly pressure independent. The pressure-dependent rate coefficients of the product channels were computed over a wide pressure-temperature range, which encompassed the experimental data.

Photovoltaic and spectroscopic properties of bacteriochlorin-based photosensitizer: molecular approach

The biophotovoltaic features of the porphyrin- and bacteriochlorin-based solar cells in different media were investigated through quantum chemistry calculations. The results show that a decrease in the chemical potential and electrophilicity facilitates the charge transfer process. Also, the bacteriochlorins have a lower energy barrier of electron injection than that of porphyrin, because of a longer charge transfer distance and less electron–hole overlap. Moreover, nonpolar solvents accelerate the free charge production, due to the favorable changes in the exciton radius and exciton binding. Improved spectroscopic properties are observed for the dyes in the solvent medium, which may be related to an increment in the probability of the electronic transition and reduced band gaps. Based on the simulated absorption spectra, bacteriochlorins are the preferred light-harvesting materials than porphyrin in the visible region. Moreover, the development of the push–pull model in the bacteriochlorin structure increases their energy conversion ability, due to advanced quantum chemistry reactivity properties. According to the final efficiency, bacteriochlorins are the preferred candidates in comparison with porphyrin to be applied in the dye-sensitized solar cells, in agreement with the experimental results.

Harnessing Photoexcited Redox Centers of Semiconductor Photocatalysts for Advanced Synthetic Chemistry

Solar photocatalysis is emerging as an environment‐friendly and sustainable energy approach for the production of fine chemicals and pharmaceuticals with high industrial and academic importance. Due to photochemical stability, tunable redox capability, and facile recyclability, semiconductor photocatalysts display remarkable advantages over molecular photocatalysts, thus attracting increasing attention. More importantly, photoexcited hole–electron pairs on semiconductor photocatalysts can accomplish two aligned redox reactions on the same semiconductor surface, resulting in unique designs of several semiconductor photocatalysis models. This review surveys recent advances in rational harnessing of photoexcited hole–electron pairs in semiconductor photocatalysts for oxidative and reductive synthetic transformations for chemical and pharmaceutical production. Depending on the catalytic behavior of the photogenerated redox centers, there are three major semiconductor photoredox reaction modes: 1) photoexcited hole‐induced oxidations, 2) photoexcited electron‐induced reductions, and 3) photoexcited electron–hole pairs co‐induced redox‐neutral reactions. The characteristics, reaction scopes, and mechanisms of these three semiconductor photocatalysis modes are discussed. Finally, the major challenges and future opportunities regarding the rational design of photoexcited redox centers in advanced synthetic chemistry are provided.

Non-Equilibrium Living Polymers.

Systems of “living” polymers are ubiquitous in industry and are traditionally realised using surfactants. Here I first review the theoretical state-of-the-art of living polymers and then discuss non-equilibrium extensions that may be realised with advanced synthetic chemistry or DNA functionalised by proteins. These systems are not only interesting in order to realise novel “living” soft matter but can also shed insight into how genomes are (topologically) regulated in vivo.

Surface analysis using X-ray photoelectron spectroscopy

This article reports on an advanced level physical chemistry laboratory experiment designed for college-level undergraduate education and for scholars who need specialized training on using and interpreting X-ray photoelectron spectroscopy. A presentation and discussion of the use of X-ray photoelectron spectroscopy in the surface characterization of six common samples are emphasized. The six samples were copper foil, copper nanoplatelets, amorphous carbon, graphite rod, uncoated and coated glass (respectively labeled as glass side A and glass side B). Survey spectra obtained for each sample were compared to known literature spectra allowing for the identification of the element types present in each sample. Furthermore, quantitative information regarding the mass percentages of each element type was also obtained and is presented herein. On an educational standpoint, this article will allow any reader, in particular, undergraduate and graduate students, to gain a better understanding of the theory and practice of X-ray photoelectron spectroscopy.

Integration of Laboratory Safety and Green Chemistry: Implementation in a Sophomore Seminar and an Advanced Organic Laboratory

Laboratory safety is a vital part of a chemical education and can be incorporated into courses throughout the chemistry curriculum. Discussions of laboratory safety can serve as an introduction to the important field of green chemistry. Exposure to this field can better prepare students for safer and more sustainable laboratory practices in research laboratories, graduate school, or careers in chemical industry. Activities integrating laboratory safety and green chemistry have been implemented in two undergraduate chemistry courses: a sophomore seminar and an advanced organic chemistry laboratory. Methods for introduction and assessment of these topics in both courses are described.

Solubility of sulfanilamide in binary solvents containing water: Measurements and prediction using Buchowski-Ksiazczak solubility model

The solubility of Sulfanilamide in binary mixtures comprising water and five organic solvents was studied at different temperatures using a spectrophotometric method. Additionally, the differential scanning calorimetry (DSC) measurements were performed to characterize the non-dissolved portion of Sulfanilamide obtained after shake-flask experiments. The Buchowski-Ksiazczak solubility model was applied to interpret the obtained experimental results. The model was successful in reproducing experimental data, as it was evidenced by several statistical measures, including the Akaike Information Criterion. The obtained parameters of the λh-equation were used for calculating the values of enthalpy of mixing. It was observed that the minimum value of enthalpy of mixing for each system is associated with those binary solvent compositions which result in the highest solubility of Sulfanilamide. Also the maximum value of the λ parameter corresponds to the composition of the mixture yielding the highest solubility. The application of COSMO-RS methodology revealed the sensitivity of solute activities and solvation Gibbs free energies to solvent-cosolvent composition. Also, there was noticed a strong correlation of these thermodynamic properties. It happened that low values of Sulfanilamide activities and their monotonous variations with the composition of considered binary solutions are associated with monotonous solubility profiles and also the reverse conclusion holds. Besides, differences in solvation of monomers and intermolecular complexes are the very probable origins of the observed trends in excess enthalpies of saturated solutions. The advanced quantum chemistry computations, including electron correlation and extended basis set, were used for quantification of affinities of systems components toward pairs formation. From the obtained values of activity equilibrium constants it was concluded that the highest affinity in all studied conditions should be attributed to Sulfanilamide dimers. It was also observed that pairs formed by Sulfanilamide with water are more thermodynamically stable than the ones with cosolvent molecules with only one exception, namely 1,4-dioxane.

Synthesis of Fused Six-Membered Lactams to Isoxazole and Isoxazoline by Sequential Ugi Four-Component Reaction and Intramolecular Nitrile Oxide Cyclization

The advanced organic chemistry experiments describe the preparation of fused six-membered lactams to isoxazole and isoxazoline by employing Ugi four-component reaction (U-4CR) and intramolecular ni...

Reflections on Course-Based Undergraduate Research in Organic and Biochemistry during COVID-19

Faculty in the Department of Chemistry and Physics at the University of New England (UNE) have recently transformed introductory and advanced chemistry curricula by embedding the high impact practice of undergraduate research. Course Based Undergraduate Research Experiences (CUREs) have provided experiential learning opportunities for over 272 students over the past three years in three different courses: University Organic Chemistry I/II (CHE 250/1 with lab), Fundamentals of Biochemistry (CHE 310/310L), and Advanced Biochemistry Laboratory (CHE 450). This communication discusses how three different faculty members in three different courses adapted workflow and curricula of chemistry CUREs laboratories to a virtual environment as dictated by the COVID-19 pandemic. Additionally, the advantages and disadvantages of curricular adaptations are discussed considering both the faculty and student experience and the importance of meeting originally defined student learning outcomes.

Developing a Virtual Reality Approach toward a Better Understanding of Coordination Chemistry and Molecular Orbitals

A virtual reality (VR) session was introduced to an advanced inorganic chemistry class, a class available to junior and senior undergraduate students at the University of California, Los Angeles. T...