What are the roles of the ligand 4′-(4-(4-carboxyphenyloxy)phenyl)-4,2′:6′,4′′-tripyridine (Hcpt) in the synthesis of lanthanide coordination polymers?

The ligand Hcpt is used in the synthesis of lanthanide coordination polymers to form coordination bonds with lanthanide ions, contributing to the structural integrity and luminescent properties of the resulting complexes.

The Hcpt ligand serves multiple roles: (1) It provides coordination sites through its nitrogen atoms in pyridine and oxygen atoms in carboxylic acid groups, forming strong bonds with lanthanide ions. (2) Its tripyridine and carboxylic groups contribute to variable coordination patterns. (3) The phenoxy group in Hcpt increases the ligand's length and rigidity. (4) The large π-conjugated system in Hcpt enables efficient energy transfer to the lanthanide center, enhancing luminescence.