Nuclear Magnetic Resonance- and Electron Paramagnetic Resonance Spectroscopic Characterization of S4N4 and (SN)x Dissolved in [EMIm][OAc].

Abstract

This work focuses on the reaction mechanism of poly(sulfur nitride) ((SN)_x, (S¹⁵N)_x), with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate [EMIm][OAc]. We compare this with the reaction of the IL with S₄N₄ or its ¹⁵N-labeled form S₄¹⁵N₄, a precursor for the synthesis of (SN)_x and (S¹⁵N)_x. After purification of the S₄N₄-IL- and S₄¹⁵N₄-IL systems via column chromatography, we characterized the reaction products with ¹H, ¹³C, and ¹⁵N nuclear magnetic resonance spectroscopy and with electron spray ionization time-of-flight mass spectrometry. Furthermore, time-resolved electron paramagnetic resonance spectroscopy and time-resolved ultraviolet-visible spectroscopy were carried out. Thus, radical intermediates were detected, which were consumed with reaction time. Finally, we postulate a reaction mechanism for the S₄N₄-IL- and S₄¹⁵N₄-IL systems and compare this with the respective data for the (SN)_x -IL- and (S¹⁵N)_x-IL-systems.