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The natural bite angles of chelating diphosphine ligands have been determined by molecular mechanics calculations using the MACROMODEL program with a modified AMBER force field. The natural bite angle (βn) is defined as the preferred chelation angle determined only by ligand backbone constraints and not by metal valence angles. Potential energy diagrams for diphosphine chelates were constructed to estimate chelate flexibility. Molecular mechanics calculations have been used to select diphosphine ligands with natural bite angles of 120° for diequatorial chelation in trigonal bipyramidal metal complexes.

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The 1 H and 13 C NMR chemical shifts of 48 industrially preferred solvents in six commonly used deuterated NMR solvents (CDCl 3 , acetone-d 6 , DMSO-d 6 , acetonitrile-d 3 , methanol-d 4 , and D 2 O) are reported. This work supplements the compilation of NMR data published by Gottlieb, Kotlyar, and Nudelman (J. Org. Chem. 1997, 62, 7512) by providing spectral parameters for solvents that were not commonly utilized at the time of their original report. Data are specifically included for solvents, such as 2-Me-THF, n-heptane, and iso-propyl acetate, which are being used more frequently as the chemical industry aims to adopt greener, safer, and more sustainable solvents. These spectral tables simplify the identification of these solvents as impurities in NMR spectra following their use in synthesis and workup protocols.

Dimethyl sulfoxide (DMSO) is widely used as a solvent for chemical reactions, as a cosolvent for crop protection formulations, and in medicines for topical administration of drugs. The potential explosion hazards associated with thermal decomposition of DMSO have been well-documented, with early reports dating back to the late 1950s. However, these explosion hazards are still underappreciated and inadequately communicated, as indicated by the fact that numerous severe accidents have occurred on both laboratory and industrial scales over the years. Differential scanning calorimetry studies show that decomposition of pure DMSO is detected at ca. 278 °C, while accelerating rate calorimetry analysis indicates that thermal decomposition of DMSO occurs at temperatures around its boiling point of 189 °C. Studies also show that the presence of certain substances can significantly lower the onset temperature of DMSO decomposition and also potentially increase the severity of the decomposition reaction through autocatalytic behavior. Further analysis of literature information indicates that there is a wide range of substances that exacerbate the thermal decomposition of DMSO, including acids, bases, halides, metals, electrophiles, oxidants, and reductants. This comprehensive review of explosion hazards associated with the thermal decomposition of DMSO and its mixtures will serve as an educational resource to alert researchers about the need to mitigate these hazards and to incentivize research toward its replacement with safer and greener solvents in the broader chemistry community.