A novel three-dimensional copper aspartate coordination compound with efficient photoluminescence

Solvothermal reaction of a copper salt, racemic aspartic acid (AspH3), and 1,2,4-triazole (TaH) leads to a nanoporous copper aspartate, Cu4(Asp)2(Ta)2(H2O)2 · 2H2O (1). The compound was characterized by FT-IR spectroscopy and elemental analysis, and the structure was determined by single-crystal X-ray diffraction. Pairs of l-Asp3− and d-Asp3− ligands in unprecedented μ 4-1,2κO:3,4κOκN coordination modes chelate pairs of adjacent copper cations to form a centrosymmetric 8n-membered rectangular pipe, and these pipes are further bridged by copper cations in four directions of the bc plane to form a 3D porous structure with approximately rectangular channels of ~ 5 × 10 Å2 along the crystallographic a-axis. Along the corners of the rectangular channels, each Ta− ligand connects three adjacent copper cations in a μ 3 coordination mode to form the final 3D porous framework with relatively large rectangular channels of ~ 2 × 8 Å2 along the a-axis. Water molecules reside in these large channels. The thermal stability and solid-state photoluminescence properties of the title compound are also investigated.