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

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.