Two photoluminescent metal–organic frameworks based on a BODIPY-derived bipyridine ligand

Abstract

Two new metal–organic open frameworks (MOFs) [Zn₃L₂(btc)₂(H₂O)]·(guests) (1), [CdL(bdc)]·(guests) (2), were successfully prepared by using a photoluminescent BODIPY-based bipyridine linker, L, and auxiliary ligands 1,4-benzenedicarboxylate (H₂bdc) and 1,3,5-benzenetricarboxylate (H₃btc), respectively. MOF 1 has a 2-fold interpenetrating three-dimensional (3D) framework with an 8-connecting body centered cubic (bcu) net, built upon a paddlewheel cluster [Zn₂(O₂CR)₄], a tetrahedrally connecting Zn and a 3-connected btc³⁻ ligand. MOF 2 has a highly open framework with a kagome-type net. It is a pillared layered structure made of 2D [Cd(bdc)] kagome sheets and L as pillars. MOF 1 was shown to exhibit permanent porosity and adsorption of N₂, H₂, CO₂ and CH₄. Both MOFs exhibited strong photoluminescent emissions at room temperature with peaks at 540 nm upon excitation, owing to a ligand L-based excited state.