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.