Tricopper Melaminate, a Metal-Organic Framework Containing Dehydrogenated Melamine and Cu-Cu Bonding

Crystals of Cu₃(C₃N₆H₃) are formed by a solid-state reaction of CuCl with melamine to form a layered framework structure with open pores running along the hexagonal axis direction of the P6/mcc structure. The compound contains the hitherto unknown (C₃N₆H₃)^3- ion, assigned as melaminate. Bonding interactions within and between Cu-Cu dumbbells, which connect melaminate ions into layers, are analyzed by density functional theory calculations of the electron localization function and directional Young's modulus. Band structure calculations reveal the material to be a semiconductor with a band gap on the order of 2 eV.