Design and synthesis of thiazole-based polydentate ligands for the assembly of new Metal-Organic Frameworks (MOFs)

Metal-Organic Frameworks (MOFs) are porous materials built from metal-containing nodes and organic linkers. The virtually infinite combination of these two ingredients for the construction of MOFs is the key factor that makes them so successful for their practical exploitation in several fields of contemporary materials science. Typical linkers are usually represented by polycarboxylic acids and polydentate N-heterocyclic bases (such as pyridines, imidazoles, pyrazoles and tetrazoles). There are fewer examples of spacers containing more than one heteroatom type in the heterocyclic core. The replacement of a carbon atom with a heteroatom (N, O, S) in the spacer structure modifies its electron density distribution. Heteroatoms may also be additional coordination sites for metal ions. Thiazoles are the simplest N,S-heterocycles. The simultaneous presence of a hard (N) and a soft (S) base may favour the coordination to both hard and soft metal ions, making the related ligand more versatile for MOFs design. With this in mind, assorted ligands featured by both condensate (TzTz) and bonded (Tz_Tz) thiazole rings have been synthesized and combined under solvothermal conditions with 3d metal salts to obtain MOFs. The results will be presented.