Synthesis, Characterization, and Magnetism of µ‐2‐Chloroterephthalato‐Bridged Binuclear Lanthanide(III) Complexes

Abstract Nine new binuclear lanthanide(III) complexes described by the overall formula [Ln2(CTPHA)(Me2bpy)4(ClO4)2](ClO4)2 (Ln = Y, La, Nd, Eu, Gd, Tb, Dy, Ho, Er; Me2bpy = 4,4′‐dimethyl‐2,2′‐bipyridine; and CTPHA = 2‐chloroterephthalate dianion), have been synthesized and characterized by elemental analyses, molar conductance measurements, and IR, ESR, and electronic spectra studies. It is proposed that these complexes have CTPHA‐bridged structures consisting of two lanthanide(III) ions. The variable‐temperature magnetic susceptibility (4–300 K) of [Gd2(CTPHA)(Me2bpy)4(ClO4)2](ClO4)2 was further measured and the magnetic analysis was carried out by means of a least‐square method to fit the observed data with the susceptibility equation derived from the spin Hamiltonian operator, Ĥ = −2J Ŝ 1 Ŝ 2, giving the exchange parameter J = −0.12 cm−1. This result indicates that the operation of a very weak antiferromagnetic spin‐exchange interaction between the adjacent gadolinium(III) and gadolinium(III) ions within the complex.