Synthesis, characterization, and luminescent properties of two new Zr(IV) metal-organic frameworks based on anthracene derivatives

Metal-organic frameworks (MOFs) are crystalline materials constructed from metal ions or clusters, connected by multidentate organic ligands. Herein, we describe the synthesis and photophysical properties of two Zr-based, anthracene-containing MOFs, assembled from 2,6-anthracenedicarboxylic acid (2,6-ADCA and 2,6-MOF) and 1,4-anthracenedicarboxylic acid (1,4-ADCA and 1,4-MOF). The 2,6-ADCA analogue formed a highly crystalline octahedral structure that is isostructural with the well-known UiO-67 frameworks. Incorporation of the 1,4-ADCA ligand, on the other hand, resulted in large rod-shaped crystals. Both MOFs exhibit linker-based luminescence. The excited-state properties of the 2,6-MOF and 1,4-MOF were examined using stead-state diffuse reflectance and emission spectroscopies and time-correlated single photon counting (TCSPC) spectroscopy. The photophysical properties of the MOFs are compared with those of the corresponding ligand in solution.