Solvent-regulated assemblies of 1D lanthanide coordination polymers with the tricarboxylate ligand.

ABSTRACT

Solvothermal reactions of the tricarboxylic acid ligand, biphenyl-3,3',5-tricarboxylic acid (H3bpta), and rare earth nitrate (Ln(NO3)3·6H2O) in the presence of KOH or DMF produced eight 1D linear coordination polymers, namely, [La(bpta)(H2O)5·(H2O)3]n (), [Pr(bpta)(H2O)5·(H2O)2.5]n (), [Nd(bpta)(H2O)5·(H2O)1.75]n (), [Sm(bpta)(H2O)5·(H2O)0.5]n () and [Ln(bpta)(DMF)(H2O)3·(H2O)]n [Ln = Eu (), Gd (), Tb (), Dy ()]. The 1D chain further assembles into a 3D supramolecular network structure through hydrogen bonds and π-π stacking among chains. Complexes and display the typical emission spectra for lanthanide-centred luminescence. The optical properties of were analysed in detail and coincide well with the structural properties. The influence of temperature on the luminescence lifetime of has been studied and different non-radiative decay paths have been discussed. The magnetic properties show that and exhibit strong spin-orbit coupling, while weak antiferromagnetic coupling exists in .