From cyanate to cyanurate: cyclotrimerization reactions towards the novel family of metal cyanurates

Abstract

The novel metal cyanurates LiSr(O₃C₃N₃) and Li₃Sr₂F(O₃C₃N₃)₂ were prepared by exothermic solid state metathesis reactions and characterized by single crystal X-ray diffraction. Crystalline powders were prepared by reactions of alkali earth halides (SrCl₂ and SrF₂) with Li(OCN) in 1:3 molar ratios, at 450 and 575 °C. The reaction with chloride yielded LiSr(O₃C₃N₃), and the reaction starting from the fluoride yielded LiSr(O₃C₃N₃)·1/2LiF, containing additional LiF in the structure. Both crystal structures revealed the presence of the (O₃C₃N₃)³⁻ ions which were formed by cyclotrimerization reaction of (OCN)⁻ ions. The reactions were monitored by differential thermal analysis. Infrared spectra of the compounds are reported.