Two-dimensional lanthanide(III) cyclic coordination polymers complexes containing dimethyl phosphate ligand: Synthesis, spectroscopic characterization, thermal analysis, and crystal structures

Three new two-dimensional lanthanide(III) cyclic coordination polymers (CPs), [Ln(mu-DMP)(3)](n) (Ln is Ce (1), Nd (2) and Sm (3); and DMP is dimethyl phosphate), were prepared from the reaction of LnCl(3)center dot XH2O (X is 7 in 1 and is 0 in 2 and 3) salts and trimethyl phosphate (TMP) ligand in mixture of H2O/CH3OH (1:10) at 40 degrees C. Suitable crystals of these complexes for crystal structure determination were obtained by slow evaporation of the produced solutions at room temperature. The three complexes were characterized by elemental analysis, IR, H-1-NMR, C-3{H-1}-NMR and P-31-NMR spectroscopy and their structures were studied by the single-crystal diffraction method. The X-ray structural analysis indicated that all three complexes have two-dimensional cyclic polymer structure. Furthermore, in complexes of 1 and 3, the Ce(III) and Sm(III) cations are six-coordinated in a distorted octahedral configuration by six bridged bidentate dimethyl phosphate ligands, while in complex 2, the Nd(III) cation is seven-coordinated in a distorted mono-capped octahedral configuration by four bridged bidentate dimethyl phosphate and two bridged tridentate dimethyl phosphate ligands. Furthermore, the thermal stability of all three complexes was studied by thermogravimetric and differential thermal analyses. (C) 2020 Elsevier B.V. All rights reserved.