Synthesis, structures, thermal behaviour, luminescence and magnetic properties of lanthanide complexes constructed from 2,6‐dimethylbenzoic acid and 5,5′‐dimethyl‐2,2′‐bipyridine

Abstract

Six new lanthanide complexes, with the formula [La(2,6‐DMBA)3(5,5′‐DM‐2,2′‐bipy)(H2O)]2 (1) and [Ln(2,6‐DMBA)3(5,5′‐DM‐2,2′‐bipy)]2 (Ln = Tb(2), Dy(3), Ho(4), Pr(5), Nd(6)) (2,6‐DMBA = 2,6‐dimethylbenzoate, 5,5′‐DM‐2,2′‐bipy = 5,5′‐dimethyl‐2,2′‐bipyridine) have been successfully synthesized and characterized. These title complexes have three different structural types. The structure of complex 1(type I) contains coordination water molecules, and the coordination number is 8. The coordination numbers of complexes 2–4 and 5–6 are 8 and 9, showing a distorted square antiprism geometry and distorted monocapped square anti‐prismatic geometry, respectively. However they have the same general formula and they can be all assembled into the same 1D, 2D supramolecular structures via the C‐H···O hydrogen bonding interactions, which is interesting in previous lanthanide complexes. The complexes were analyzed by TG‐DSC/FTIR. In addition, the visible light luminescence experiments of Tb (III) complex was carried out, and the characteristic luminescence behavior of strong green color was shown. And the fluorescence lifetime and intrinsic quantum yield were calculated. The magnetic properties of complexes 2–4 were also studied, and the results showed that complex 3 and complexes 2, 4 have ferromagnetic interactions and antiferromagnetic interactions, respectively.