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…

The dissolution of cobalt­(II) chloride in an appropriate binary alcohol solvent yields an equilibrium mixture, consisting of the differently colored octahedral (pink in color) and tetrahedral (blue in color) cobalt­(II) coordination complexes, which can exhibit a brilliant and reversible pink-to-blue color transition over a ~10 °C window - i.e.,…

A laboratory experiment in which [superscript 1]H NMR and UV-vis spectroscopies are applied to probe the temperature dependence of a monomer-dimer equilibrium involving a cyclopentadienone derivative is described and discussed. Details of the data analysis for extraction of equilibrium constants from the raw experimental data from both techniques…

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…

The optical spectrometer is a widely established and widely used scientific instrument for analyzing biochemical samples. However, it is expensive, bulky, and requires an external power source and a computer to operate, which makes it difficult to use in resource-limited countries and in remote locations. Advancement in smartphone technology has…

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…

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…

Stereoselective reduction of ketones to alcohols using baker's yeast is a classic experiment in the undergraduate laboratory. Here we illustrate the reduction of racemic ethyl 2-fluoro-3-oxobutanoate to the corresponding alcohol using a set of four commercially available ketoreductases (KREDs). The reaction sets two stereocenters with four…

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…

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…

Space telescopes are some of the most precise and complicated machines ever built. Not only must they survive the harshness of space travel, but they also need to be incredibly accurate: misalignments by fractions of a millimetre can have huge effects on the quality of the images they capture. In 1990, the Hubble Space Telescope became the first…

Infrared (IR) spectra of biologically derived materials display distinct absorption bands correlating to individual macromolecules: protein, polysaccharide, lipid, and nucleic acids. A series of experiments aimed at teaching qualitative bioorganic spectroscopy using attenuated total reflectance (ATR) Fourier transform infrared (IR) with biological…

The NMR spectrometer is a commonly used spectroscopic instrument that records resonance frequencies of nuclei present in molecular systems. While the NMR frequencies fall within the radio frequency regime for a given molecular system, they are presented in terms of chemical shifts in the audio frequency regime, thereby having the versatility to be…

Purpurogallin (PPG), an orange-red crystalline compound from nutgalls and oak bark, is an exemplar of numerous, ubiquitous natural colorants, biosynthesized through oxidative dimerization-decarboxylation of phenolic compounds. It possesses antioxidant, anticancer, and anti-inflammatory effects. Herein, a robust method is presented to allow…

One of the most important aspects associated with the modern production of chemicals is sustainability. To teach students and young scientists to design their research in the spirit of "sustainable development," students should be made accustomed to seeking solutions that are not only efficient and cost-effective but also safe and…