SYNTHESIS AND CHARACTERIZATION OF OXAMIDO-BRIDGED PENTANUCLEAR [Cu(II)]₄Ln(III) COMPLEXES WITH A [14]N₄ MACROCYCLIC OXAMIDE

Abstract

Seven novel oxamido-bridged pentanuclear copper(II)-lanthanoid(III) complexes of a macrocyclic oxamide have been prepared by the strategy of “complexes as ligands” and characterized by elemental analyses, conductivity measurements, IR and UV-Visable spectra. The complexes are of formula [(CuL)₄Ln](ClO₄)₃·xH₂O [Ln = La(III), Pr(III), Nd(III), Sm(III), Gd(III), Dy(III) and Er(III), x = 1, 2 or 3, H₂L = 2,3-dioxo-5,6:13,14-dibenzo-7,12-bis(ethoxycarbonyl)-1,4,8,11-tetraazacyclotetradeca-7,11-diene]. The temperature dependence of the magnetic susceptibility of the [Cu₄Gd] complex has been investigated and revealed ferromagnetic interaction between the Cu(II) and Gd(III) ions with the exchange integral J_CuGd = 0.76 cm⁻¹ (based on Ĥ-2JΣŝ _i ŝ _j .

ACKNOWLEDGEMENT

This work was supported by the National Natural Science Foundation of China (No. 20071019).