A family of tetranuclear Ln(III) complexes based on a terphenyl dicarboxylic acid ligand: synthesis, structure, and photophysical properties

The design of ligands that can coordinate lanthanide ions in predictable arrangements is a long-standing theme in coordination chemistry, because it underpins the development of functional molecules with potential applications that exploit the unusual electronic properties of these ions. Herein, we describe how a new terphenyl dicarboxylate ligand can chelate the lanthanide ions Gd(III), Tb(III), or Dy(III) into a family of tetranuclear complexes with the general formula [Ln4(L)4(NO3)2(HCOO)2(solvent)6]. The structural parameters of these complexes are discussed in detail, and investigation of their photophysical properties shows that the ligand facilitates ligand-sensitised emission from the complexes, both in the solid state and in the solution phase.