Synthesis and magnetism of μ-phthalato binuclear lanthanide(III) complexes (Ln = Gd, Tb, Ho, Er)

Abstract Four novel binuclear Ln(III) complexes containing the dianion of phthalic acid(phth) as a bridging ligand have been synthesized, namely [(Ln 2 (phth)(phen) 4 ] (ClO 4 ) 4 ·xH 2 O (Ln = Gd, Tb, Ho, Er; Phen = 1,10-phenanthroline; phth = dianion of phthalic acid). The complexes have been characterized by elemental analyses, IR, electronic spectra, ESR and conductances. The variable-temperature magnetic susceptibility (4–300 K) of complex Gd 2 [(phth)(phen) 4 ](ClO 4 ) 4 has been determined. A satisfactory fit to the theoretical curve derived from the spin Hamiltonian operator, Ĥ = − 2JŜ 1 · Ŝ 2 was obtained by the least squares method. The exchange interaction parameters are J = −0.25 cm −1 indicating the existence of a weak antiferromagnetic spin exchange interaction between the lanthanide ions in the complex.