Preparation, crystal structure, time-dependent density theory and properties of a novel organic-inorganic hybrid up-conversion luminescence tetranuclear complex

A novel up-conversion luminescence tetranuclear sodium complex [Na4(5-(carboxymethyl 2-oxo-propyl) amino isophthalic acid)(H2O)9] is synthesized by a solvothermal reaction, and its crystal structure is determined by single-crystal X-ray diffraction. The title complex crystallizes as a triclinic system with the P 1 ¯ space group and exists as an isolated tetranuclear complex. Numerous intermolecular hydrogen bonds and van der waals forces form a three-dimensional supramolecular network. Solid-state diffuse reflectance data show that there is a wide optical band gap of 2.91 eV. The solid-state photoluminescence spectrum reveals that the complex shows an up-conversion emission in the blue region of the light spectrum. Time-dependent density functional theory calculations reveal that this emission can be attributed to ligand-to-ligand charge transfer.