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Most chemistry students struggle with interpreting and understanding NMR (nuclear magnetic resonance) spectra and the general concepts of NMR spectroscopy. NMR spectroscopy seems to be difficult to both teach and learn. Therefore, the corresponding courses should be investigated in more detail. We conducted a survey with N = 39 German university lecturers in NMR spectroscopy on their course content as well as on their estimations on the importance of certain topics for understanding NMR spectroscopy in detail and found the most recent problems, conceptions, and content structure. The participants were asked to rate a list of items (belonging to [superscript 1]H NMR spectroscopy) twice: First in terms of appearance in their lecture or course and second according to their personal relevance. Our results showed that, on the one hand, students learn about the physical and chemical backgrounds and theoretical basics for understanding [superscript 1]H NMR spectroscopy and, on the other hand, about essential knowledge for practical analyzing and interpreting [superscript 1]H NMR spectra. The most covered and most important topics are the practical ones related to spectra interpretation, e.g., chemical shift, spin-spin coupling, and further background knowledge for peak analysis. Therefore, most lecturers focus on teaching usage-oriented conceptual knowledge more than theoretical backgrounds, which means that analyzing spectra is paramount, especially for beginner students. Furthermore, this review visualizes an evidence-based ranking for the most covered and as most relevant estimated NMR spectroscopy lecture contents as well as students' greatest learning difficulties in Germany. Lecturers and students are now able to validate their lectures or course structure.

A didactic sequence is proposed using an infrared puzzle and a didactic questionnaire for the teaching-learning of infrared spectroscopy at the upper secondary level. The didactic sequence that was designed was implemented in person in the subject of Chemistry IV at the high school level, corresponding to the sixth semester of the curriculum of the National School of Sciences and Humanities (CCH), Vallejo Campus, of the National Autonomous University of Mexico. In the didactic sequence, students understand the importance of functional groups where they determine organic compounds, by identifying regularities, properties, and structure of alcohols, aldehydes, ketones, and carboxylic acids. After applying the didactic sequence, a post-test questionnaire was applied, and the results showed that the students significantly improved their knowledge of IR when using the puzzle that allowed them to correctly identify the bands that identify the carbonyl group.

The imine condensation reaction is commonly addressed in second semester organic chemistry classrooms as imines and their derivatives are found in many pharmaceutical scaffolds and biological and catalytic processes. Despite this, imine condensations are still absent from many organic chemistry laboratory curriculums. The work discussed here focuses on comparing the reactivity of the imine condensation with methyl t-butyl ether versus dichloromethane as the solvent as a way to better understand green chemistry along with analyzing steric and electronic effects on reaction. Three primary butyl amines with differing levels of steric hindrance are reacted with a wide variety of substituted aromatic aldehydes that range from electron donating to electron withdrawing. The products are analyzed using [superscript 1]H NMR spectroscopy, and the percent conversion for each reaction is determined. The results of this work and strategies for implementation of an imine condensation project in second semester organic chemistry laboratory are presented.

Students in a typical instrumental analysis course may learn more than 30 analytical techniques. There are more than 150 components associated with the instrumentation that they learn. To help students organize this large amount of information, we classified these components into four categories: sources, samples, discriminators, and detectors. In this work, color-coded pictograms are used to help students identify components associated with a particular instrumental technique. For example, a UV-visible spectrophotometer can be depicted by using four color-coded pictograms. Pictograms were created for instrumentation on each of the following topics: spectroscopy, electrochemistry, chromatography, elemental analysis, surface analysis, and thermal analysis. Methods to incorporate these pictograms into the instrumental analysis course and assess their effectiveness are provided.

Microplastics have been detected in most ecosystems around the world. They affect the environment and organisms in it, including humans and possibly their health. Hence, the analysis of microplastic occurrence in the environment is highly relevant. However, there are only a few practical and easy-to-implement methods published for school use, and therefore, microplastics still receive little attention in the classroom. This review presents an approach for separation and detection of microplastic particles in sediment with secondary school students based on methods used in current research. After sieving and density separation, the fluorescence marker Nile Red is used to selectively stain microplastic particles. Subsequently, the particles can be detected using a DIY low-cost fluorescence photobox. It offers an opportunity to address the problems associated with microplastics in a school context and can be used as an example for further discussion.

We present a showcase of our experience with videos complementing analytical chemistry lectures to familiarize undergraduate students with instrumental element analysis. This includes a detailed account of how we planned, produced, and utilized a video to review the course content at the end of the semester. The analytical case study focused on the determination of magnesium in two well water samples with emphasis on flame atomic absorption spectroscopy, while also comparing results with inductively coupled plasma optical emission spectroscopy and titration measurements. During the lecture, we engaged students by asking them for suggestions on how to carry out the measurements before showing the respective video sections. A survey among the students revealed a remarkably positive response to this approach. We demonstrate our video production approach by making decisions and choices from the video production, such as recording and editing, explicit and conclude with practical advice for planning and producing similar videos to visualize case studies.

This paper describes a data set of IR, MS, H-1 NMR, C-13 NMR, DEPT, and 2D NMR spectra designed for undergraduate teaching. The data files are provided as MestReNova documents containing all the available spectra for each of the 251 different compounds in the data set. The spectral data in these files can be processed, manipulated, copied, and pasted as needed by faculty to support teaching organic chemistry and instrumental analysis and for specialized courses in spectroscopy and organic synthesis. The compounds in the database were selected to provide examples for interpreting spectra and unknowns for teaching interpretation and to support teaching synthesis mechanisms. Additional MestReNova documents are provided to demonstrate how the data can be used for a variety of common undergraduate course topics-introducing IR, MS interpretation, NMR interpretation, data processing, and spectroscopy unknowns for students.

The synthesis of a [2]rotaxane through three- or five-component coupling reactions has been adapted to an organic chemistry experiment for upper-division students. The experimental procedure addresses the search for the most favorable reaction conditions for the synthesis of the interlocked compound, which is obtained in a yield of up to 71%. Moreover, the interlocked nature of the rotaxane is proven by NMR spectroscopy. The content of the sessions has been designed on the basis of a proactive methodology whereby upper-division undergraduate students have a dynamic role. The laboratory experience not only introduces students to the chemistry of the mechanical bond but also reinforces their previous knowledge of basic organic laboratory procedures and their skills with structural elucidation techniques such as NMR and FT-IR spectroscopies. The experiment has been designed in such a customizable way that both experimental procedures and laboratory material can be adapted to a wide range of undergraduate course curricula.

An organic chemistry experiment designed for senior undergraduates focuses on bifunctional catalysis, a critical yet often omitted topic at the undergraduate level, but essential for advanced studies in chemistry. By utilization of a tertiary amine-thiourea catalyst in the asymmetric Michael addition reaction, the experiment showcases the superiority of bifunctional catalysis over traditional monofunctional approaches. Comprehensive training in designing control experiments, performing flash chromatography, and analyzing results with NMR and HPLC techniques equip students with modern synthetic skill sets. This experiment features easy operation and a relatively short time (4.5h, including 2-2.5 h reaction time). More importantly, it bridges the educational gap in understanding advanced catalytic mechanisms and techniques in organic chemistry.

Triboluminescence is a fascinating phenomenon that can engage students' interest in chemistry. However, safe, cost-effective, and accessible laboratory experiments featuring highly triboluminescent substances are limited. To bridge this gap, we present a simple, rapid, semimicro test tube preparation of the visually engaging manganese complex [MnBr[subscript 2](Ph[subscript 3]PO)[subscript 2]], conducted by high school students. During the laboratory session, students practice various laboratory skills, including handling semimicro quantities of substances, ascertaining the melting point, and recrystallizing the synthesized complex. They also investigate the complex's triboluminescent, fluorescent, and magnetic properties through straightforward and illustrative experiments. Furthermore, this laboratory activity has been successfully implemented in an undergraduate chemistry didactics course for chemistry educators. The experiment's simplicity, combined with the safety of starting materials and use of nontoxic solvents, makes it an optimal choice for a variety of educational environments, such as high school and university laboratory sessions, science clubs, and public science outreach activities.

Chemometric techniques such as partial least-squares (PLS) regression have been applied with huge success to a wide array of chemical problems including multicomponent analysis of analytes in complex mixtures. Despite this, there are few examples of laboratory pedagogical exercises that involve students in the acquisition of chemical data from infrared spectroscopic-based instrumentation, followed by quantitative chemometric analysis using PLS. In this article, we present a computational activity that introduces undergraduate students in an instrumental analysis laboratory setting to data acquisition using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy followed by data analysis using PLS. The first part of the activity involved students creating mixture designs of binary terpene components consisting of p-cymene and limonene. These mixtures were then analyzed using an ATR-FTIR spectrometer, where students became familiarized with the instrument and were shown how to characterize and differentiate the aforementioned terpenes using their generated FTIR spectra. The second part of the activity involved preprocessing the acquired FTIR spectral data from the first part followed by the simultaneous quantitative determination of the prepared terpenes using PLS. On the basis of student surveys, it can be concluded that this convenient and inexpensive activity was ultimately successful in introducing students to the use of chemometrics for quantitative analysis of terpenes using an ATR-FTIR. This easy-to-do two-week activity can be used as a standalone for instrumental analysis laboratory classes and can even be integrated in advanced courses in applied spectroscopy and chemometrics.

Quinacridone red and violet are visually different colors, an observation confirmed by their visible reflectance spectra and CIE L*a*b* coordinates. However, their IR spectra are extremely similar. Though chemically identical, the two quinacridones are polymorphs. In this experiment, designed for and tested by nonscience majors, the pigments are extracted from oil paints with hexane in a short procedure involving sonification and centrifugation. ATR-FTIR spectra of the recovered brilliantly colored powders reveal the presence of a calcium carbonate filler in one of the two paints. Factoring out the carbonate bands, the spectra are nearly identical. Students must reconcile the evidence of color and the evidence of the spectra.

In this paper, we present a concise and technique-heavy route to the synthesis of dimedone for a second-year organic chemistry curriculum. Our preparation of dimedone guides students through a Michael addition followed by a Dieckmann cyclization, basic ester hydrolysis, and thermal decarboxylation, while allowing time for mechanistic discussion and analysis of the product. The wide variety of techniques covered led this to be a pedagogically diverse experiment. This task is thoroughly tested and suitable for a 6 hour laboratory class (with a 1 hour lunch break) or two 3 hour stand-alone sessions.

Vibrational fine structure observed in the published He-I UV photoelectron spectra of H[subscript 2] and N[subscript 2] molecules recorded at room temperature and under microwave excitation or at 700 °C have been reexamined and compared with calculations of the Franck-Condon factors (FCFs) using simple harmonic oscillator wave functions and/or those obtained using Morse potentials. In general, FCFs are used to explain vibronic transitions of molecules observed in the UV-vis and photoelectron spectra of diatomic and polyatomic molecules, which can be computed using differing levels of complexity. We advocate constructing the vibrational wave functions numerically, rather than analytically, with the help of a program such as Excel, Origin, or Python. In this way students can also verify the normalization and orthogonality of the wave functions using numerical integration routes provided within these programs. Special attention is drawn to possible deviations of the FCFs of the vibrationally excited molecules from those of the ground states.

In this laboratory experiment, first-semester organic chemistry students use mechanistic reasoning to propose possible outcomes for the reaction of vanillin isobutyrate with a hydride source. The students subsequently run the reaction, isolate the product, and acquire its infrared spectrum. The experiment provides students with the opportunity to hone their skills at proposing mechanisms and interpreting IR spectra. It also serves as an introduction to the chemistry of carbonyl-containing functional groups.

Quantum dots are colloidal semiconductor nanocrystals that display size-dependent electronic and optical properties. These materials are a visual demonstration of a quantum-mechanical effect. Here we present a laboratory exercise for undergraduate/Bachelor students as an introduction to colloidal nanocrystals and quantum dots. The students synthesize three sizes of indium phosphide (InP) nanocrystals and perform one core/shell synthesis of indium phosphide cores shelled with zinc sulfide (InP/ZnS). The obtained quantum dots are characterized by quantitative UV--vis, photoluminescence, and 1H NMR spectroscopy. Students are acquainted with several concepts: nanocrystal synthesis, colloids, Beer-Lambert law, quantum confinement, photoluminescence, and surface chemistry. For each concept, background information is provided, rendering this report a comprehensive introduction for students and teachers. Indium phosphide is a safer material to handle in the undergraduate lab compared to cadmium selenide (CdSe), cesium lead bromide (CsPbBr[subscript 3]), or lead sulfide (PbS) nanocrystals.

This paper introduces hands-on curricular modules integrated with research in atmospheric ice nucleation, which is an important phenomenon potentially influencing global climate change. The primary goal of this work is to promote meaningful laboratory exercises to enhance the competence of students in the fields of science, technology, engineering, and math (STEM) by applying an appropriate methodology to laboratory ice nucleation measurements. To achieve this goal, three laboratory modules were developed with 18 STEM interns and tested by 28 students in a classroom setting. Students were trained to experimentally simulate atmospheric ice nucleation and cloud droplet freezing. For practical training, this work utilized a simple freezing assay device called the West Texas Cryogenic Refrigerator Applied to Freezing Test (WT-CRAFT) system. More specifically, students were provided with hands-on lessons to calibrate WT-CRAFT with deionized water and apply analytical techniques to understand the physicochemical properties of bulk water and droplet freezing. All procedures to implement the developed modules were typewritten during this process, and shareable read-ahead exploration materials were developed and compiled as a curricular product. Additionally, students conducted complementary analyses to identify possible catalysts of heterogeneous freezing in the water. The water analyses included: pH, conductivity, surface tension, and electron microscopy-energy-dispersive X-ray spectroscopy. During the data and image analysis process, students learned how to analyze droplet freezing spectra as a function of temperature, screen and interpret the data, perform uncertainty analyses, and estimate ice nucleation efficiency using computer programs. Based on the formal program assessment of learning outcomes and direct (yet deidentified) student feedback, we broadly achieved our goals to (1) improve their problem-solving skills by combining multidisciplinary science and math skills and (2) disseminate data and results with variability and uncertainty. The developed modules can be applied at any institute to advance undergraduate and graduate curricula in environmental science.

Purpose: We explore a new approach to the study of cognitive effort involved in listening to speech by measuring the brain activity in a listener in relation to the brain activity in a speaker. We hypothesize that the strength of this brain-to-brain synchrony (coupling) reflects the magnitude of cognitive effort involved in verbal communication and includes both listening effort and speaking effort. We investigate whether interbrain synchrony is greater in native-to-native versus native-to-nonnative communication using functional near-infrared spectroscopy (fNIRS). Method: Two speakers participated, a native speaker of American English and a native speaker of Korean who spoke English as a second language. Each speaker was fitted with the fNIRS cap and told short stories. The native English speaker provided the English narratives, and the Korean speaker provided both the nonnative (accented) English and Korean narratives. In separate sessions, fNIRS data were obtained from seven English monolingual participants ages 20-24 years who listened to each speaker's stories. After listening to each story in native and nonnative English, they retold the content, and their transcripts and audio recordings were analyzed for comprehension and discourse fluency, measured in the number of hesitations and articulation rate. No story retellings were obtained for narratives in Korean (an incomprehensible language for English listeners). Utilizing fNIRS technique termed sequential scanning, we quantified the brain-to-brain synchronization in each speaker-listener dyad. Results: For native-to-native dyads, multiple brain regions associated with various linguistic and executive functions were activated. There was a weaker coupling for native-to-nonnative dyads, and only the brain regions associated with higher order cognitive processes and functions were synchronized. All listeners understood the content of all stories, but they hesitated significantly more when retelling stories told in accented English. The nonnative speaker hesitated significantly more often than the native speaker and had a significantly slower articulation rate. There was no brain-to-brain coupling during listening to Korean, indicating a break in communication when listeners failed to comprehend the speaker. Conclusions: We found that effortful speech processing decreased interbrain synchrony and delayed comprehension processes. The obtained brain-based and behavioral patterns are consistent with our proposal that cognitive effort in verbal communication pertains to both the listener and the speaker and that brain-to-brain synchrony can be an indicator of differences in their cumulative communicative effort.

The pharmaceutical and medicine manufacturing industry has become the largest industrial sector for the employment of chemists, indicating a need for experiments with a pharmaceutical sciences context in the undergraduate chemistry curriculum. In the pharmaceutical industry, testing drug dissolution is a key analytical task for solid oral dosage forms that is performed in different phases of drug development to test the release behavior of new formulations, ensure consistency between manufacturing lots, and help predict the "in vivo" absorption of the drug substance after administration. However, there are a limited number of laboratory experiments in dissolution testing developed for the undergraduate chemistry curriculum. To help students obtain hands-on experience in dissolution testing, a protocol has been developed for an undergraduate chemistry laboratory course for students to build a dissolution apparatus, monitor dissolution processes, model the dissolution to extract kinetic parameters, and evaluate the consistency between dissolution curves with FDA regulated methods. Students successfully collected dissolution curves and completed the modeling analysis with nonlinear least-squares fitting. The designed dissolution protocol has been evaluated to have consistency and reproducibility to be implemented in the undergraduate chemistry laboratory curriculum.

Experimentation is a contributing factor to the interest and meaningful learning of Science. In Geology and Earth Science, the effects of soil textures, settlements, and water-holding capacity are parameters for landslides in Barotac Viejo and other flooded areas. Landslides are triggered during heavy rainstorms, causing severe property damage and casualties. This experimental study aims to determine how these parameters are factors for landslides and give accurate information to Science teachers. The study uses two methods to provide ease and continuity of measurements and settings using the Fourier Transform Infrared(FTIR) spectroscopy in analyzing the soil textures. The Imhoff cone instrument is for the settling and water-holding capacity of the soil. FTIR Soil analysis reveals that contents of clay and organic matter directly affect soil water-holding ability due to the larger surface area. A landslide-prone zone has a lesser settling time except for the sand that settles fastest due to larger masses. This study is crucial for science teachers teaching geology and earth sciences besides forecasting and preventing geohydrological processes and developing better landslide warning strategies to mitigate risks and reduce socioeconomic damage.

Machine learning (ML) is extensively applied in chemistry, particularly in vibrational spectroscopy. However, few teaching examples effectively demonstrate the capabilities of ML in classifying polymeric materials, exhibiting subtle spectral differences that elude visual discrimination. This study presents a teaching example specifically tailored for undergraduate students to acquire the skills necessary to employ ML models in the classification of infrared spectral data from different types of polyvinyl butyrals (PVBs). The course encompasses fundamental knowledge of PVB structure and synthesis, a comprehensive spectral analysis workflow for constructing classification models, specific data processing techniques, and practical implementation of a student-synthesized PVB product in a laboratory demonstration. Assessment of students' knowledge acquisition is conducted through assignments, and student attitudes toward this course via submitted self-reflection surveys are discussed. This study underscores the efficacy of classroom examples in developing students' abilities and fostering their interest in amalgamating chemistry and artificial intelligence. The knowledge and techniques acquired in this course hold practical implications for quality control, process monitoring, and material identification in industry.

Short chain fatty acids (SCFAs) are produced in the gut as a result of microbial action on ingested dietary fiber and have been associated with several health benefits. Herein an undergraduate student experiment that uses gas chromatography equipped with either a flame ionization detector or mass spectrometer for the analysis and quantitation of SCFAs in synthetic fecal material is described. The experiment provides students with valuable sample preparation and instrument operation skills and provides an opportunity for students to perform quantitative analysis using the method of internal standards. Subsequently, the experiment provides an opportunity for students to consolidate their learning of the key theoretical concepts including chromatographic separation by gas chromatography, and methods for confirming analyte identity using each detector type. Due to recent global interest in gut health, the experiment is topical and of interest to students. The experiment is designed for upper-division undergraduate analytical chemistry students.

General spectroscopy is known to be difficult for novice students due to its complex and abstract nature. In this study we used a first-year chemistry Mini Spec laboratory activity to uncover language barriers to student learning in spectroscopy. Analysis revealed that language barriers generated conceptual difficulties for English as Second Language (ESL) students. As well as demonstrating difficulty with understanding of the origin of spectral lines identified in prior research, this work surfaces previously unreported language difficulties which were characterized in terms of technical and non-technical language. These include observations that 'refract' and 'diffract' appeared poorly delineated for students, the teleological animism of 'jump' to describe excited electron transitions towards the ground state, and the non-technical term 'discrete' being difficult for students to understand and construct meaning for. In addition to this, students battled with the symbolic language required to depict the formation of spectral lines. Several solutions to the language difficulty are proposed including the re-sequencing of macroscopic, sub-microscopic and symbolic teaching and reconsidering the usefulness of certain non-technical terms for teaching and learning spectroscopy.

The Beer-Lambert law is a fundamental relationship in chemistry that helps connect macroscopic experimental observations (i.e., the amount of light exiting a solution sample) to a symbolic model composed of system-level parameters (e.g., concentration values). Despite the wide use of the Beer-Lambert law in the undergraduate chemistry curriculum and its applicability to analytical techniques, students' use of the model is not commonly investigated. Specifically, no previous work has explored how students connect the Beer-Lambert law to absorption phenomena using submicroscopic-level reasoning, which is important for understanding light absorption at the particle level. The incorporation of visual-conceptual tools (such as animations and simulations) into instruction has been shown to be effective in conveying key points about particle-level reasoning and facilitating connections among the macroscopic, submicroscopic, and symbolic domains. This study evaluates the extent to which a previously reported simulation-based virtual laboratory activity (BLSim) is associated with students' use of particle-level models when explaining absorption phenomena. Two groups of analytical chemistry students completed a series of tasks that prompted them to construct explanations of absorption phenomena, with one group having completed the simulation-based activity prior to the assessment tasks. Student responses were coded using Johnstone's triad. When comparing work from the two student groups, chi-square tests revealed statistically significant associations (with approximately medium to large effect sizes) between students using the simulation and employing particle-level reasoning. That said, submicroscopic-level reasoning did not always provide more explanatory power to students' answers. Additionally, we observed the productive use of a variety of submicroscopic light-matter interaction models. We conjecture that engaging with BLSim provided new submicroscopic-level resources for students to leverage in explanations and predictions of absorption phenomena.

The laboratory is a complex environment where the three levels of the chemistry triplet coincide. As the laboratory environment places a large demand on the working memory of students, cognitive load theory can address overload which causes barriers to learning. Breaking down barriers requires iterative phases of analysis/exploration, design/construction and evaluation/reflection over multiple cycles which are the hallmarks of design-based research. In a complex setting, managing change and redressing teaching approaches can be difficult to navigate. Design-based research incorporates iterative phases in which theory informs decision making. This paper uses the context of a laboratory exercise of emission spectra to illustrate how the cognitive load theory can be used in tandem with design-based research to support student learning in the exercise. Using this approach, it was possible to show how barriers to student understanding, including task demands and conceptual demands were supported through proposed approaches focusing on extraneous, intrinsic and ultimately germane cognitive load.

Cycloadditions in combination with multicomponent reactions are among the most valuable synthetic tools used by organic chemists to construct cyclic and heterocyclic compounds in a straightforward way. Although cycloadditions, such as the Diels--Alder reaction, are mainly covered in basic and advanced organic courses for undergraduate students, few experiments are reported in the literature for undergraduate organic chemistry laboratories. Here we describe a new experiment to illustrate the multicomponent imino-Diels-Alder cycloaddition to obtain a tetrahydroquinoline derivative under green chemistry conditions. Different synthesis procedures, including solvent-free reactions, microwave assisted reactions, use of a deep eutectic solvent, and star anise oil as starting material, were evaluated by students. The structure of the synthesized compound was confirmed by NMR spectroscopy ([superscript 1]H, APT, COSY, HSQC), IR spectroscopy, mass spectrometry, and melting point analysis. In addition, the stereochemistry was also proposed by students based on the NMR data.

High-resolution mass spectrometry (HRMS) is an analytical technique that is typically used by mass spectrometry experts. However, with recent advancements, it is becoming more accessible to students in organic chemistry laboratories. Still, a significant knowledge gap exists between these experts and students. A straightforward laboratory experiment in HRMS is crucial to bridging this gap. This experiment outlines key steps for understanding HRMS, including defining the resolution, estimating the molecular formulas using accurate mass, understanding the calibration, selecting the appropriate ionization methods and calibration compounds, and validating the results. Following these steps will enable students to better grasp HRMS and effectively use it in their research.

This work presents a homemade multirole 3D-printed modular spectrometer(MPMS), which can be easily assembled like bricks and expanded with several modules to measure different types of spectra, such as UV-vis absorption, fluorescence emission, flame emission/absorption, glow discharge, and even Raman spectra. The spectrometer is designed to be cheap, flexible, and its inner structure is displayable, making it suitable for a range of applications and age groups. The assembly process allows for a clear understanding of the basic structure of the monochromator, the core component of spectrometers, as well as reveals the connections and similarities between different spectral analysis methods. Despite being easily disassembled, the spectrometer is robust, easy to calibrate, and highly precise, making it suitable for both qualitative and quantitative analysis. This study provides a valuable tool for those seeking a practical and educational approach to spectroscopy.

Antioxidants are molecules that act against free radicals, and this effect can bring many benefits to health and society. Antioxidants can be found in various matrices of nature, such as fruits and plants. Some studies have shown that "Rhizophora mangle," a typical mangrove plant, is rich in antioxidants. People report its use for medicinal purposes, such as treating diabetes and high blood pressure. In Espírito Santo, Brazil, the bark extract of the plant is used as a waterproofing agent in the making of the capixaba clay pan, a cultural symbol of the state. Thus, this context was used as a reference for the application of chemical knowledge addressed in the teaching of Instrumental Analytical Chemistry. The participants were undergraduate chemistry students at the Federal University of Espírito Santo (Ufes). Two experiments were designed to be performed by groups of four to five students during 2-4 h laboratory classes. The students employed analytical techniques for spectrophotometric (FRAP, ferric reducing antioxidant power) and electrochemistry (CRAC, ceric reducing antioxidant capacity) determination of the total antioxidant capacity of "R. mangle" bark extracts. The experimental results indicated that the extracts of the plant have significant antioxidant capacity compared to trolox. By performing different extraction procedures and analytical techniques, students were able to compare, analyze, and evaluate strategies aimed at determining antioxidant capacity. The antioxidant capacity assays can be expanded to analyze other matrices of interest to professors and students.

The carbonyl group of an aldehyde or ketone reacts with different types of nucleophiles through a nucleophilic addition reaction. When the nucleophile is water, the product obtained is a "gem"-diol or geminal diol. This functionalization is unstable and quickly reverts to the parent carbonyl group. The chemistry of "gem"-diols is not usually covered in depth in organic chemistry courses. Herein, we propose a two-step activity to study the isolation of different "gem"-diols: an organic laboratory practice designed for undergraduate students combined with an in-class activity. The approach focuses on the study of heterocyclic compounds with aldehyde moieties using solution and solid-state nuclear magnetic resonance combined with X-ray crystallography.

Chemistry in water is an emerging field that fulfills the fifth principle of green chemistry: replacing toxic organic solvents with their benign counterparts. Although some pharmaceutical industries have developed and adopted chemistry in water, its implementation in teaching laboratories is still limited. Therefore, we have designed an experiment dedicated to the undergraduate curriculum covering sustainable, completely organic-solvent-free amide coupling, which is one of the most heavily used reactions in the pharmaceutical industry. The designed experiment aims to acquaint students with the 12 principles of green chemistry, inform them of the shortcomings of the traditional synthetic procedures of amide coupling, make them aware of waste generation from toxic organic solvents, and show them the effectiveness of water as a benign reaction medium. With the training throughout the lab sessions, students were taught micellar catalysis, NMR (nuclear magnetic resonance) spectroscopy, IR (infrared) spectroscopy, separation techniques, and safety data.

Spectroscopic methods of molecular structure identification and analysis constitute part of inorganic, organic, analytical, and physical chemistry in both undergraduate and postgraduate chemistry curricula. Despite the importance and complexity of the relevant concepts, it is only recently that studies on spectroscopy have started to appear in the education literature. These studies have focused on student interpretation of spectra. The purpose of this study was to deal with further fundamental issues underlying spectroscopy. We first present students' perceptions of their knowledge about various aspects of spectroscopy such as the extent of their understanding of the basic concepts of UV, IR, NMR, and MS. In addition, we probed students' declarative knowledge about basic concepts and features of spectroscopy. The results showed that mass spectrometry was perceived to be the least understood method, while IR was perceived to be the best understood. Students considered their ability to identify the spectroscopic method used for obtaining a spectrum to be relatively satisfactory, as also was, but to a lesser extent, their ability to extract information from the spectrum. Students rated their understanding of the differences among the four spectroscopic methods as moderate. Concerning students' declarative knowledge about basic concepts and features of spectroscopy, such as the physical meaning of "wavenumber" in IR spectroscopy and of "part per million" in NMR spectroscopy, "performing integration", and the "resolving power" of a spectrometer, the results were mostly poor. Interestingly, a clear difference was observed between performance on questions at high versus basic levels of declarative knowledge.

Plant-derived natural products are an important source of potential medicines and continue to have a major impact on the drug discovery process. Natural product discovery assignments provide an opportunity to present various experimental techniques to undergraduate students in introductory medicinal chemistry. This assignment was developed to serve as a meaningful hands-on exercise to introduce undergraduate Chemistry students to the common procedure in the early phase of drug discovery using inexpensive corn silk, in which the final year undergraduate student used Recycling Preparative High-Performance Liquid Chromatography to separate and purify steroids from corn silk. The student used advanced spectroscopic methods such as UV, IR, and one- and two-dimensional NMR to elucidate the structures of these steroids. The cytotoxic activity of these steroids was also evaluated and found to be non-cytotoxic to normal human MRC-5 cells at 60 µg/mL via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. With this assignment, students gain meaningful multidisciplinary hands-on exercises with the common procedure in the early stages of drug discovery and understand the process of isolating natural compounds that may lead to the development of new drugs.

The chemistry of 4d and 4f metals was investigated at the undergraduate level in an effort to incorporate f-element chemistry in the curriculum. This was accomplished through microwave-assisted synthesis of 1,10-phenanthroline (phen) coordination compounds [Eu(phen)(subscript 3)](PF[subscript 6])[subscript 3] and [Ru(phen)(subscript 3)](PF[subscript 6])[subscript 2], and embedding the coordination compounds in polystyrene (PS) beads. Through a combination of 1-D/2-D spectroscopic techniques, the metal-phen coordination compounds in solution and in the solid state were probed. It was validated that the strong interaction between the phen ligand and Ru[superscript 2+] is due to the diffuse nature of the 4d orbitals. The interaction resulted in a low energy MLCT band, which provides opportunities for excitation at lower energies using 4d metals. In contrast, the phen ligand and core Eu[superscript 3+] 4f orbitals exhibited a weak interaction. This was supported by variable-temperature NMR (VT-NMR) measurements, which revealed relatively well-separated proton resonances with minimal differences in chemical shifts for the phen ligand at 25°C and the [Eu(phen)(subscript 3)](PF[subscript 6])[subscript 3] compound at -42°C, indicating a weak Eu-N interaction. The weak interaction resulted in the formation of an aqua-containing complex in solution evidenced by emission lifetime measurements. Despite the weak interaction, selective excitation (via ligand [pi]-[pi]* versus direct f-f) of the Eu[superscript 3+] compound allowed for color tuning, leading to the generation of a cool white light. Electron probe microanalysis (EPMA) of the metal-embedded PS beads indicated relatively monodispersed distribution of the metal complexes in the polymer.

The dangers of organic dye pollutants and environmental pollution improvement through photocatalytic degradation are important courses in applied chemistry programs in universities. Zinc oxide (ZnO)-based nanomaterials are potent catalytic agents against organic dyes, but few experiments are available for students to understand their role and mechanism in class. Herein, we designed a comprehensive experiment across 24 class hours for undergraduates to investigate the photodegradation of colored organic dyes, including methylene blue, methyl orange, methyl violet, rhodamine B, basic fuchsin, and thymolphthalein, by a nanocomposite composed of ZnO-coated graphene oxide (ZnO/GO). This nanomaterial was prepared using a facile heating reflux method within 1 h. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were introduced to students to characterize the synthesized products. Students could observe the time- and dose-dependent degradation as well as the reusability of ZnO/GO. Additionally, the addition of t-butanol, benzoquinone, and triethanolamine, scavengers of hydroxyl radical ([superscript .]OH), superoxide anion ([superscript .]O[superscript 2-]), and hole (h[superscript +]), respectively, to the degradation system allowed them to master the underlying catalytic mechanism of ZnO/GO. This experiment improves students' understanding of the photocatalytic effect of ZnO nanomaterials and stimulates them to engage in the field of applied chemistry and thus is worth recommending to undergraduates.

A cornerstone activity in undergraduate organic laboratories revolves around students running instrumental analysis on their products and interpreting their spectra. They are left to link the theory they have learned in lecture to practical spectral interpretation. Students often memorize benchmark interpretations of peaks, such as the broad alcohol absorbance in infrared spectroscopy (IR). However, students often do not correlate the absorbance frequency to the actual vibrational mode. Given more nuanced spectra to interpret, like the difference between a hydrogen and a deuterium on an alcohol, students often miss the differences between the spectra. The GAMESS computational software package accessed through the Web interface ChemCompute is successfully used by students here to generate IR spectra of different isotopically labeled alcohols. This Web-based portal provides multiple benefits to the students: (1) The computational software is accessible through any browser on most common operating systems (including Chromebooks), (2) generating IR spectra for multiple products allows students to predict differences in spectra to compare to their actual IR data reinforcing prediction in the scientific method, and (3) the software links the differences in isotopes to structural vibrational modes visualized in the software allowing students to link theory to practice in spectral interpretation.

Background: Educational research has been conducted mainly by using behavioural approaches. Whilst such methods provide invaluable insights into the field, several important questions such as 'how do we learn?' and 'what mechanisms cause individual differences?' cannot be answered thoroughly by using only behavioural approaches. In the last three decades, the advances of neuroimaging technologies and computational power have allowed researchers to investigate these questions beyond behavioural measures that provide complementary knowledge about human brain. Aim: One of the most recent neuroimaging techniques that holds much promise for use in educational settings is functional near-infrared spectroscopy (fNIRS). This article aims to introduce the fNIRS technique to educational researchers interested in neurocognitive mechanisms of academic learning and achievements to further promote the growing field of Educational Neuroscience. Method: We present the properties of the fNIRS device, its basic principles and important considerations when planning an fNIRS study. Results: Functional near-infrared spectroscopy is a portable, cost-effective and easy-to-handle neuroimaging device that allows experimentation in naturalistic settings such as in the school. Conclusion: Even though several articles describe different applications and technical features of the fNIRS technique, there is still a need for materials with a more accessible language for those unfamiliar with neuroscientific and technical terms.

Computational and atmospheric chemistry are two important branches of contemporary chemistry. With the present topical nature of climate change and global warming, it is more crucial than ever that students are aware of and exposed to atmospheric chemistry, with an emphasis on how modeling may aid in understanding how atmospherically relevant chemical compounds interact with incoming solar radiation. Nonetheless, computational and atmospheric chemistry are under-represented in most undergraduate chemistry curricula. In this manuscript, we describe a simple and efficient method for simulating the electronic absorption spectral profiles of atmospherically relevant molecules that may be utilized in an undergraduate computer laboratory. The laboratory results give students hands-on experience in computational and atmospheric chemistry, as well as electronic absorption spectroscopy.

Electrophilic aromatic substitution reactions are common in the organic chemistry laboratory. These reactions, while ubiquitous, use corrosive reagents and halogenated or hydrophobic solvents that produce expensive and hazardous waste streams. The carboxylation of phenols (Kolbe-Schmitt reaction), although aqueous, typically involves conditions (high pressure/temperature) that are not well-suited fora large teaching laboratory. The following experiment modifies the Kolbe-Schmitt process for ambient pressures and aqueous reflux temperatures. This procedure is safe, simple, and inexpensive and uses [superscript 13]C NMR as an analytical tool to confirm product synthesis and investigate changes in molecular symmetry.

A major obstacle that teachers face when they begin their spectroscopy lessons is the lack of a spectrophotometer, mostly due to its relatively high cost. In the present study, the construction of a low-cost do-it-yourself type of instrument is reported. Its construction, as a part of a problem-based scenario, would also help students to enhance their chemical literacy. Moreover, the creation of a Jupyter Notebook called "Spectrophotometry" is also described. With this tool, students and teachers, within a few clicks, will derive absorption and fluorescence spectra and do kinetics studies without any difficulty and the need for time-consuming data postprocessing software. Finally, the views of a group of students on the construction and ease of use of our spectrophotometer are discussed in detail.

The pharmacologically active lignans sesamin and sesamolin are minor components of sesame oil and ingredients in OTC dietary supplement capsules. We report an introductory undergraduate organic laboratory experiment combining natural product isolation and spectral analysis in which students isolate a mixture of sesamin and sesamolin by either (1) dry column vacuum chromatography (a convenient alternative to flash column chromatography) of commercial sesame oil using an apparatus constructed from common laboratory glassware or by (2) solid-liquid extraction of commercial sesame seed lignan dietary supplement capsules. Two recrystallizations from methanol remove most of the sesamolin to afford crystalline sesamin, which, due to its 2-fold rotational symmetry, students can easily identify and characterize by NMR. During a second laboratory period, students perform a 5 min, test tube-scale reaction of sesamin with catalytic BF[subscript 3]:OEt[subscript 2] to promote its epimerization to episesamin, a diastereomer of sesamin lacking rotational symmetry, and the sesamin/episesamin ratio in the resulting product mixture is established by [superscript 1]H NMR integration. Students are asked to propose a mechanism for this epimerization based on their knowledge of the reactivity of benzyl ethers under acidic conditions.

A comprehensive laboratory-style teaching activity involving the synthesis, characterization, and analysis of structure-activity relationships of metal-organic framework (MOF) nanozymes was developed specifically for undergraduates at Tianjin University. The students acquired familiarity with the general approach in synthesizing MOFs by solvothermal method using substituted MIL-101­(Fe)-X (MIL is an acronym for Materials of Institute Lavoisier). Several modern characterization methods were taught, including powder X-ray diffraction and fluorescence spectroscopy for assessing MIL-101­(Fe)-X crystal structures and superoxide dismutase (SOD)-like activities. In particular, students were guided by the instructor to investigate the relationship between structural differences in MOFs caused by ligand changes and their SOD-like activities. The Hammett relationships were later demonstrated to be an accurate method of quantifying structure-activity relationships of MIL-101­(Fe)-Xnanozymes. By participating in this laboratory experience, students are able to improve their scientific thinking, practical abilities, and teamwork. Additionally, a fundamental principle of material design can be conveyed to undergraduates based on the structure-activity relationship, thereby deepening their understanding of nanozymes and the course's content.

The methodology and mathematical treatment of several classic multivariate methods for the analysis of spectroscopic data is demonstrated in a straightforward way that can be used as a basis for teaching an undergraduate introductory course on chemometric analysis. The multivariate techniques of classical least-squares (CLS), principal component regression (PCR), and partial least-squares (PLS), as well as the univariate Beer's law method have been described and compared, building students' understanding by starting with the univariate method and progressing step by step into the multivariate methods. Equations for the production of regression vectors from training set spectral data are described and their use demonstrated for the prediction of constituent concentrations on a separate validation set of spectra. Extreme care is taken to ensure consistency in variable formatting of data matrices. This provides a key foundation to understand how spectral data are manipulated using these different mathematical approaches for building quantitative regression models. Each method is applied to a real-world data set, and the results are discussed to show students the types of information that can be gleaned from each method. A training set comprising 20 infrared absorbance spectra containing 3 constituents (benzene, polystyrene, and gasoline) of known composition are used to demonstrate the matrix operations for each regression method. A separate set of 12 real-world napalm samples (containing benzene, polystyrene, and gasoline) are used as a validation set to demonstrate the ability to utilize the regression models on an unknown data set. A toolbox (PNNL Chemometric Toolbox) written in MATLAB language is supplied in the Supporting Information and can be used as a companion for understanding the development and deployment of the chemometric algorithms described in this paper. The data sets of the infrared spectra are also supplied, allowing users to build and inspect the chemometric models on their own. Finally, the Toolbox includes scripts to assist users in loading their own data sets into MATLAB and performing CLS, PCR, and PLS on their data.

Here we showcase an undergraduate teaching laboratory in which students synthesize and characterize colloidal nanoparticles of organic semiconductors and assess their suitability for applications in printed electronics such as solar cells and bioelectronics. Scanning electron microscopy, UV-visible spectroscopy, and photoluminescence spectroscopy are used to characterize the nanoparticles, and students learn how to match electron donating (p-type) and electron accepting (n-type) materials based on the literature material characteristics: HOMO, LUMO, and charge carrier mobility. This teaching laboratory exercise was developed as part of the University of Newcastle Centre for Organic Electronics Spring School program and includes data from a cohort of 44 undergraduate student participants. The teaching laboratory exercise is applicable to undergraduate students in multiple disciplines, including physical chemistry, chemical engineering, materials science, and physics, and can be altered to suit time, level of experience, and instrumentation availability. The exercise utilizes a post-practical quiz to provide feedback and assess embedded knowledge. The student cohort responded well to the post-practical quiz, for example, 94% correctly identified the purpose of synthesizing nanoparticles of organic semiconductors for printed electronics applications being eco-friendly high-throughput processing benefits as well as the ability to nanostructure the photoactive layer to optimize exciton dissociation. This Laboratory Experiment also provides a set of Student Learning Objectives (LOs) and a detailed account of observations/outcomes in attaining these LOs for the student cohort at the Spring School program. This experiment is an introductory lesson in colloidal nanomaterials and gives students exposure to the chemistry, physics, and materials science concepts of organic electronics.

Infrared (IR) technologies have been universally acknowledged as a valuable pedagogical tool for exploring novel and abstract scientific subjects in science education. This study explores the roles of IR images played in middle school students' Evidence-based Reasoning (EBR) process in support of the understanding of the heat radiation process. Specifically, we implement image processing algorithms explicitly for the visual artifacts mentioned in students' descriptions of the radiation phenomenon to obtain the numeric representations of their corresponding features. Meanwhile, the quality of those descriptions is further coded with the guidance of the EBR framework for indicating students' understanding levels of the phenomenon. Finally, the associations between the numerical image features and the quality of descriptions are analyzed to examine the effectiveness of the IR visual artifacts in helping students understand the heat radiation process. The analytical results found that the image features are further positively correlated with the quality of the descriptions generated by students for the heat radiation. The results further suggest the IR images have the potential of driving students to think proactively and explore detailed procedural changes in learning the heat radiation process. Finally, our study calls for the integration of interdisciplinary instructional approaches in science education to reduce students' cognitive load and guide learning attention, for example, incorporating visualization and relevant processing approaches to present and analyze the otherwise invisible abstract process to help students make sense related knowledge more easily.

This communication describes an updated experiment of peptide synthesis, involving determination of the loading capacity of a Fmoc-protected amino functionalized resin using UV-vis spectroscopy and a subsequent synthesis of a dipeptide in order to exemplify the experimental solid-phase synthesis procedure as an alternative technique in organic synthesis. Analysis of the crude dipeptide by liquid chromatography and mass spectrometry is also envisaged. Relevance of solid-phase peptide synthesis (SPPS) to access proteins or small-molecule peptide-based chemical probes is shown to indicate the considerable importance of achieving theoretical and practical skills of a biochemistry/medicinal chemistry graduate in this scientific area. The experiment combines skills in organic and analytical chemistry and focuses on improving students' abilities to recall knowledge acquired in different disciplines and their use in order to accomplish an experiment, essentially procedurally simple, however, requiring basic theoretical background regarding amino acid reactivity and protecting groups as well as principles of UV-vis spectrophotometric determinations and mass spectrometry. The work may be conveniently split along two laboratory classes or performed at once. In addition, the students can work not only in pairs of two but also in groups containing a greater number because the tasks can be assigned individually.

Eleven different laboratory experiments were designed and executed throughout a semester to provide a meaningful research experience for 23 undergraduate biochemistry majors at UTSA. The topic of the semester was based on the idea of exploring new aspects to enhance our understanding of how the human body uses cytochrome P450 enzymes to metabolize artemisinin, an endoperoxide-containing plant natural product used to treat malaria. Biochemical techniques introduced to the students included computational (dry lab) techniques: the use of bioinformatics tools to design plasmids for protein expression, software to analyze the 3-dimensional structure of proteins, metabolomics software to analyze enzyme-catalyzed reaction extracts by mass spectrometry, and docking software to dock ligands into the active site of proteins. In addition, students performed experimental (wet lab) techniques including: a transformation experiment to incorporate plasmid DNA into bacteria, an extraction of plasmid DNA from bacterial cells, performing enzymatic incubations and preparing samples for analysis by mass spectrometry, and running an SDS protein gel electrophoresis. The semester ended with the use of a web-based program to allow students to visualize the proteins they were studying throughout the semester with a virtual reality headset. This course was taught for the first time at the university, so this manuscript should inspire ideas for future biochemistry laboratory courses taught in the course based undergraduate research experiences (CUREs) format.

The pharmaceutical industry relies heavily on analytical techniques for identifying and characterizing drug compounds. In this experiment, undergraduate pharmacy students explored the applications of near-infrared spectroscopy for pharmaceutical analysis and its potential for identifying patterns and relationships among pharmaceutical samples. In addition, they were introduced to the chemometrics field using classical pretreatment and data exploration methods. To reduce the need for expensive instrumental equipment, we have developed a small and affordable device based on the DLP NIRscan Nano EVM by Texas Instruments using free software solutions and a 3D-printed case for Raspberry Pi single-board computers. The goal of the experiment was to guide students through all the necessary steps for measuring and analyzing samples using NIR spectroscopy and to encourage their learning through the application of mathematical methods in a defined laboratory setting.

A Fourier transform infrared (FTIR) experiment appropriate for an upper-level undergraduate laboratory such as chemical instrumentation is described. Students collect FTIR spectra of four protio-solvents and their deuterated analogues. In addition to qualitatively observing C-H and O-H peaks shift to lower energy upon deuteration, students apply a simple harmonic oscillator model to predict the magnitude of the shifts and gain an understanding of the relationship between reduced mass and vibrational frequencies. Vibrational calculations are then performed to corroborate the experimental results and allow students to visualize the normal modes involved via animations of the vibrations. This experiment is suitable to be used as either an in-person or online laboratory.