Synthesis, identification and chemical features of high-purity trimethylselenonium iodide

Abstract

High-purity (99.8%±1.1) trimethylselenonium iodide (TMSeI) was synthesized from dimethyl selenide and methyl iodide. Its chemical structure was confirmed using the spectroscopic methods of nuclear magnetic resonance, Fourier transform infrared and electrospray ionization-mass spectrometry. Some thermodynamic properties of the pure TMSeI were studied with differential scanning calorimetry, and its decomposition point and entropy were determined to be 157.7 °C and 100.7 kJ mol⁻¹, respectively. The chromatographic and UV absorption behavior of the trimethylselenonium cation was also studied and the photochemical and chemical stability of TMSe⁺ and its decomposition products under varying microwave digestion conditions were examined. Some peculiar, yet interesting chemical properties on the stability of the compound were revealed. This is the first time that the chemical properties of this compound are comprehensively studied by various techniques and from different angles. The high purity of the synthesized compound allows it to be used as a primary standard compound in analytical method development and in basic and environmentally related studies.

Keywords:

• trimethylselenonium iodide synthesis
• NMR
• FTIR
• ESI-MS
• DSC
• microwave digestion

Acknowledgements

Funding from the Natural Sciences and Engineering Research Council of Canada through the Discovery Grant program and the Strategic Network MITHE-SN is greatly acknowledged. We sincerely thank G. Arteca for his interpretation of spectra. We also express our gratitude for the helpful comments from anonymous reviewers.