Synthesis and magnetism of mu-isophthalato dinuclear lanthanide(III) complexes

Seven new mu-isophthalato dinuclear lanthanide(III) complexes, namely [Ln(2 )(IPHTA)( Me-2-phen)(4)-(ClO4)(2)](ClO4)(2) (Ln = La, Nd, Sm, Eu, Gd, Ho, E r), where Me-2-phen denotes 2, 9-dimethyl-1, 10-phenanthroline (Me-2-phen), IPHTA represents isophthalate dianion, have been synthesized and character ized by elemental analyses, molar conductance measurements, IR, ESR and ele ctronic spectra. The variable-temperature magnetic susceptibilities of [Gd- 2(IPHTA)( Me-2-phe)(4)(ClO4)(2)](ClO4)(2)] complex were measured in the tem perature range of 4-300 K and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, (H) over cap = -2J (S) over cap(1).(S) over cap(2), giving the exchange parameter J = - 0.19 cm(-1). This result is commensurate with a weak antiferromagnetic spin-exch ange interaction between Gd(III)-Gd(III) ions within the complex.