Magnetic and luminescent properties of lanthanide coordination polymers with asymmetric biphenyl-3,2′,5′-tricarboxylate

Abstract

Eight isostructural lanthanide coordination polymers [Ln(bptc)(phen)(H₂O)]_n (Ln = Dy for 1, Eu for 2, Tb for 3, Gd for 4, Sm for 5, Nd for 6, Yb for 7, Pr for 8) were successfully prepared based on bridging asymmetric polycarboxylate ligand biphenyl-3,2′,5′-tricarboxylic acid (H₃bptc) and chelating 1,10-phenanthroline (phen) coligand. Single crystal X-ray analysis reveals that complexes 1–8 have a (3,6)-connected CdI₂-type coordination network consisting of paddle-wheel dimers [Ln₂(CO₂)₄]. The magnetic and fluorescent properties of 1–8 have been investigated. Significantly, the Dy(III) complex 1 behaves with slow relaxation of the magnetization, where the frequency-dependent out-of-phase signals are noticed.