Isostructural series of [{Al(H2O)6}{Ln(pda)3}].10H2O: Synthesis, structure and photoluminescence

Synthesis and photoluminescence properties of polymer chains based on pre-designed heterometallic Al4Ln4 molecular rings

Presented herein is a series of chain compounds based on pre-designed heterometallic aluminum-lanthanide (Al-Ln) Al4Ln4 molecular rings. Their photoluminescence quantum yield (PLQY) with Eu3+ (30.41%) and Tb3+ (41.44%) is at a high level among the clusters containing four Ln ions. This study significantly extends the family of Al-Ln heterometallic clusters and demonstrates the synergistic effect of heterometallic ions in enhancing their properties.

Crystal structures of two SmIII complexes with dipicolinate [DPA]2- ligands: comparison of luminescent properties of products obtained at different pH values

The formation of the two title compounds, Na3[Sm(DPA)3]·14H2O tris-odium tris-(pyridine-2,6-di-carboxyl-ato-κ3 O 2,N,O 6)samarate(III) tetra-deca-hydrate, Na3[Sm(C7H3NO4)3]·14H2O, and catena-poly[[[di-aqua-(6-carb-oxy-pyridine-2-carb-oxyl-ato-κ3 O 2,N,O 6)samarium(III)]-μ-pyridine-2,6-di-carboxyl-ato-κ4 O 2,N,O 6:O 2] tetra-hydrate], {[Sm(C7H3NO4)(C7H4NO4)(H2O)2]·4H2O}n, depends on the pH value adjusted with NaOH solution. In both crystal structures, the coordination spheres of the SmIII cations were found to be best described by a tricapped trigonal prism (TTP), with a more regular O6N3 donor set for Na3[Sm(DPA)3]·14H2O than that of O7N2 for [Sm(DPA)(HDPA)(H2O)2]·4H2O. The supra-molecular features of both crystal structures are dominated by O-H⋯O hydrogen bonds between water mol-ecules and the O atoms of the dipicolinato ligands. Samples were made from solutions at pH = 2, pH = 5, pH = 7, and pH = 10, and the crystals present in each sample were ground to a powder. The powder samples were analyzed with powder X-ray diffraction and luminescence spectroscopy. The splitting of the bands in the luminescence spectra recorded on powders at 77 K was observed to vary with the pH.

The effect of weighted averages when determining the speciation and structure–property relationships of europium(iii) dipicolinate complexes

Europium(iii) dipicolinate complexes have been a model system in lanthanide solution chemistry for decades, here it is investigated in unprecedented detail.