Thermal deprotonation and condensation of melamine in the presence of indium(iii)chloride

Abstract

The thermal condensation of melamine into molecules melam, melem, and the one-dimensional polymer melon has already been reported. An interesting question arises about the impact of other compounds being present in this process of thermal conversion. The solid-state reaction of C₃N₆H₆ with InCl₃ leads to a novel compound featuring deprotonated melam units in a supramolecular assembly, based on the [C₁₂N₂₀H₈]⁴⁻ anion that is interconnected in the structure via N–In–N bonding. The reaction pathway of the formation of this compound is investigated by thermal analysis and the crystal structure of unique (NH₄)[(InCl₂)₃(C₁₂N₂₀H₈)]·⅔[InCl₃(NH₃)] is reported as well as its photoluminescence properties.