Isolation and Characterization of the Cyamelurate Anion [C₆N₇O₃]^3- derived from a Disordered Carbon Nitride Material

James R. Holst and Edward G. Gillan* Department of Chemistry University of Iowa, Iowa City, Iowa 52242

Our group reported on the rapid solid state decomposition of the molecular precursor, trichloromelamine (C₃N₃(NHCl)₃), into a robust carbon nitride material that contains one of the highest nitrogen contents yet reported for carbon nitride (CN_x) materials. Characterization by powder X-ray diffraction, FT-IR, and NMR indicated the material was possibly of a planar nature (i.e., graphitic) with retention of the triazine (C₃N₃) moiety and extensive sp² bonding character, as evidenced by the data. To date, the proposed structures for CN_x materials usually involve the incorporation of 2° or 3° amine-linked triazine rings. However, the exact extended structure has not been determined, given the disordered nature of the material. This presentation will describe base hydrolysis of CN_x solids to form alkali salts of the planar cyamelurate anion, [C₆N₇O₃]^3-. This result suggests that the initial triazine precursor is likely condensed into a heptazine-based structure (C₆N₇) during decomposition. Several control experiments will also be presented to support this revised CN_x structural hypothesis.