Publications by authors named "J M Simmie"
Kinetics of tautomerisation of thiouracils and cognate species at low temperatures: theory experiment.
Phys Chem Chem Phys
December 2024
Hydrogen-atom tunnelling is an important component in some chemical reactions particularly at low temperatures ≤300 K. Recent experiments by Rostkowska [H. Rostkowska, L.
View Article and Find Full Text PDFArticle Synopsis
- Peroxides play a crucial role in industries like plastics and rubber, primarily as initiators in polymerization reactions because their O-O bonds break easily, releasing reactive free radicals.
- Some organic peroxides can be highly explosive, raising safety concerns during their production and use since they are strong oxidizers.
- Researchers used advanced chemistry models to calculate the bond dissociation energies (BDE) of various organic peroxides, including simpler and more complex types, to assess their safety risks, aiming to establish a reliable standard for future evaluations.
The solvent-free elimination of sulfinic acid and aromatization of 1,6-trans-substituted bis(arylsulfone) trienes is reported. It is shown that sublimation can be used as a 'green' method to combine the thermal transformation of six trienes and the crystal growth of the resulting 4-(phenylsulfonyl)biphenyls. When the sublimation conditions are carefully controlled, high quality single crystals of the 4-(phenylsulfonyl)biphenyls are obtained.
View Article and Find Full Text PDFA recent suggestion that acetamide, CHC(O)NH, could be readily formed on water-ice grains by the acid induced addition of water across the C≡N bond has now been shown to be credible. Computational modeling of the reaction between R-CN (R = H, CH) and a cluster of 32 molecules of water and one HO proceeds catalytically to form first a hydroxy imine R-C(OH)═NH and second an amide R-C(O)NH. Quantum mechanical tunneling, computed from small-curvature estimates, plays a key role in the rates of these reactions.
View Article and Find Full Text PDFArticle Synopsis
- The study focuses on supramolecular synthons and their role in designing pharmaceutical cocrystals, particularly analyzing the similarities between malaria drug pyrimethamine and antibiotic trimethoprim, both derivatives of 2,4-diaminopyrimidine.
- It highlights the different binding interactions of common coformers like sulfamethazine and various acids with pyrimethamine and trimethoprim, revealing unique hydrogen bonding patterns and structural motifs.
- The research also presents instances of cocrystal-salt polymorphism in trimethoprim/azelaic acid and discusses novel three-component cocrystals involving sulfa drugs that exhibit a distinct ternary synthon.