Homodinuclear lanthanide 9-anthracenecarboxylate complexes: field induced SMM and NIR-luminescence.

Abstract

Six homodinuclear lanthanide complexes with formula [Ln2(l2-9-AC)4(9-AC)2(phen)2] (Ln(III) = Nd (1), Eu (2), Gd (3), Tb (4), Er (5) and Yb (6) are reported and complexes 1-3 and 6 are structurally characterized. 9-HAC = 9-anthracenecarboxylic acid, phen = 1,10-phenanthroline. The luminescence properties of compounds 1-6 have been studied at different temperatures in the solid state and show the sensitization of the 4f-4f emission bands in the NIR range for compounds 1, 5 and 6. The molar magnetic susceptibility measurements of 1-6 in the 2-300 K temperature range indicate weak antiferromagnetic exchange for the isotropic Gd(III) compound 3. Furthermore, slow relaxation of the magnetization is found in complexes 5 and 6 with effective energy barriers of 9.5 cm 1 (0.1 T) and 22.7 cm 1 (0.15 T), respectively.