Simulation of the chemical interactions of luminescent lanthanide complexes series [Ln(cin)3(H2O)3]·Hcin and [Ln2(cin)6(bpy)2] using DFT calculations

In this work, DFT calculations were conducted to understand the interactions of two luminescent complexes series, named [Ln(cin)3(H2O)3]·Hcin and the [Ln2(cin)6(bpy)2] (where cin = hydrocinnamate anion and bpy = 2,2′-bipyridine). For the reduction of the computational cost in the geometry optimization calculations, the PBE-D2 and the GGA + U methodologies were tested, even as the 4f electrons treatment, in the core and in the valence shell of the lanthanide metals.As a result of the electronic structure calculations, the lattice parameters of these complexes was obtained and corroborated by a comparison between the simulated and experimental diffractograms. The projected density of states and the charge density analysis were made for a better understanding of the electronic structure and the stabilization of these complexes, like the importance of some ligands and the difference of the interaction between the rare-earth metals and the ligands.It could be concluded that there is no need to compute the spin polarization and to include the hubbard correction in order to conduct a structural analysis of these rare-earth metal complexes. The electronic density maps show that the structures are mainly stabilized by charge transfer between the ligands and the rare-earth cations. This result also corroborates the geometry optimizations performed with the DFT-D2 method, which indicate that the computation of the Van der Waals forces are negligible.

Graphical abstractIn this work, DFT calculations were conducted to understand the electronic structure of the two luminescent complexes series, named [Ln(cin)3(H2O)3]·Hcin and the [Ln2(cin)6(bpy)2] (where cin = hydrocinnamate anion and bpy = 2,2′-bipyridine). For a reduction in the computational cost in the optimization geometry calculations, the PBE-D2 and the GGA + U methodologies were tested, even as the 4f electrons treatment, in the core or in the valence shell of the lanthanide metals. As a result of the electronic structure calculations, the structure of these complexes was obtained and corroborated by a comparison between the simulated and experimental diffractograms. The projected density of states and the charge density analysis were made for a better understanding of the electronic structure of these complexes, like the importance of some ligands and the difference in the interaction between the rare-earth metals and the ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide