Luminescent Ln-Ionic Liquids beyond Europium

Searching in the Web of Knowledge for “ionic liquids” AND “luminescence” AND “lanthanide”, around 260 entries can be found, of which a considerable number refer solely or primarily to europium (90%, ~234). Europium has been deemed the best lanthanide for luminescent applications, mainly due to its efficiency in sensitization, longest decay times, and the ability to use its luminescence spectra to probe the coordination geometry around the metal. The remaining lanthanides can also be of crucial importance due to their different colors, sensitivity, and capability as probes. In this manuscript, we intend to shed some light on the existing published work on the remaining lanthanides. In some cases, they appear in papers with europium, but frequently in a subordinate position, and in fewer cases then the main protagonist of the study. All of them will be assessed and presented in a concise manner; they will be divided into two main categories: lanthanide compounds dissolved in ionic liquids, and lanthanide-based ionic liquids. Finally, some analysis of future trends is carried out highlighting some future promising fields, such as ionogels.

Construction of a 1-D Sm(iii) coordination polymer with a long-chain Schiff base ligand: dual-emissive response to metal ions

A 1-D coordination polymer [Sm(HL)₂(NO₃)]_n was constructed using a new flexible Schiff base ligand that has a long-chain (CH₂)₁₀ backbone, and it shows dual-emissive response to metal ions, especially to Co²⁺ at the ppm level.

Luminescent Polynuclear Zn- and Cd-Ln Square-Like Nanoclusters With a Flexible Long-Chain Schiff Base Ligand

Two series of Zn-Ln and Cd-Ln nanoclusters [Ln₄Zn₈L₂(OAc)₂₀(OH)₄] [Ln = Nd (1), Yb (2), and Sm (3)] and [Ln₂Cd₂L₂(OAc)₂(OH)₂(OCH₃)₂] [Ln = Nd (4), Yb (5), and Sm (6)] were prepared using a long-chain Schiff base ligand with a flexible (CH₂)₂O(CH₂)₂O(CH₂)₂ chain. All these clusters show square-like structures. The Schiff base ligands show “linear” configurations in the structures of 1-6, and the metric dimensions of Zn-Ln and Cd-Ln clusters measure ~8 × 14 × 21 and 8 × 12 × 12 Å, respectively. The study of luminescence properties shows that the Zn/L and Cd/L chromophores can effectively transfer energy to the lanthanide ions, and 1-6 show visible and NIR emissions.

Self-assembly of luminescent Zn–Ln (Ln = Sm and Nd) nanoclusters with a long-chain Schiff base ligand

Two Zn–Ln rectangular nanoclusters [Zn₈Ln₄L₈(OAc)₈](OH)₄ (Ln = Sm (1) and Nd (2)) with sizes of 9 × 19 × 28 Å were constructed using a long-chain Schiff base ligand built around a flexible (CH₂)₃O(CH₂)₂O(CH₂)₃ backbone, and their visible and NIR luminescence properties were determined.

Construction of luminescent high-nuclearity Zn–Ln rectangular nanoclusters with flexible long-chain Schiff base ligands

Two types of 8- and 14-metal Zn–Ln nanoclusters were prepared using long-chain Schiff base ligands and their interesting visible and NIR luminescence properties were investigated.

Nanofiber electrospinning in samarium complex-doped PMMA

Herein, an electrospinning process of samarium complex-doped PMMAs was carried out to fabricate ultrafine fibers with a uniform diameter of about 230 nm.