A melamine–adipate-bridged binuclear copper complex with supramolecular architecture: synthesis, structures, and properties of [Cu2(MA)(ad)2]·H2O and (MA)·(H2ad)·H2O

Complexes of melamine with adipic acid and Cu(CH3COO)2 · H2O, [Cu2(MA)(ad)2] · H2O (1), and (MA) · (H2ad) · H2O (2) (MA = melamine; H2ad = adipic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared, UV-Vis, and single crystal X-ray diffraction. Both crystallized in the triclinic space group P-1. In 1, MA and adipate bond to copper to construct a 3-D supramolecular framework in an unusual noninterpenetrated pseudo-primitive cubic topology constructed from a four-connected binuclear Cu(II) secondary building unit. A variety of intra- or inter-molecular hydrogen bonds exist. In 2, the 3-D supramolecular structure is formed through strong interactions among MA, adipic acid, and lattice water. Thermal analysis, photoluminescence, and calculations were also performed.