Designing Dimeric Lanthanide(III)-Containing Ionic liquids

Herein, we report on the preparation of liquid dimeric lanthanide(III)-containing compounds. Starting from the design of dimeric solids, we demonstrate that by tuning of anion and cation structures we can lower the melting points below room temperature, whilst maintaining the dimeric structure. Magnetic measurements could establish the spin-spin interactions of the neighboring lanthanide(III) ions in the liquid state at low temperatures, and matched the interactions of the analogous crystalline solid compounds.

Designing a new type of magnetic ionic liquid: a strategy to improve the magnetic susceptibility

In order to improve the magnetic susceptibility, MILs were prepared by incorporating lanthanide ions in both the cation and anion.

Synthesis, structural characterization and luminescence properties of 1-carboxymethyl-3-ethylimidazolium chloride

A microcrystalline carboxyl-functionalized imidazolium chloride, namely 1-carboxymethyl-3-ethylimidazolium chloride, C₇H₁₁N₂O₂⁺·Cl^-, has been synthesized and characterized by elemental analysis, attenuated total reflectance Fourier transform IR spectroscopy (ATR-FT-IR), single-crystal X-ray diffraction, thermal analysis (TGA/DSC), and photoluminescence spectroscopy. In the crystal structure, cations and anions are linked by C-H...Cl and C-H...O hydrogen bonds to create a helix along the [010] direction. Adjacent helical chains are further interconnected through O-H...Cl and C-H...O hydrogen bonds to form a (10-1) layer. Finally, neighboring layers are joined together via C-H...Cl contacts to generate a three-dimensional supramolecular architecture. Thermal analyses reveal that the compound melts at 449.7 K and is stable up to 560.0 K under a dynamic air atmosphere. Photoluminescence measurements show that the compound exhibits a blue fluorescence and a green phosphorescence associated with spin-allowed (¹π←¹π*) and spin-forbidden (¹π←³π*) transitions, respectively. The average luminescence lifetime was determined to be 1.40 ns for the short-lived (¹π←¹π*) transition and 105 ms for the long-lived (¹π←³π*) transition.

Towards ionic liquids with tailored magnetic properties: bmim+ salts of ferro- and antiferromagnetic CuII3 triangles

With proper selection of counteraction and pH control, CuII3-pyrazolate anions can form a ferromagnetic low-melting solid, or an antiferromagnetic viscous paste.

Dysprosium electrodeposition from a hexaalkylguanidinium-based ionic liquid

The rare-earth element dysprosium (Dy) is an important additive that increases the magnetocrystalline anisotropy of neodymium magnets and additionally prevents from demagnetizing at high temperatures. Therefore, it is one of the most important elements for high-tech industries and is mainly used in permanent magnetic applications, for example in electric vehicles, industrial motors and direct-drive wind turbines. In an effort to develop a more efficient electrochemical technique for depositing Dy on Nd-magnets in contrast to commonly used costly physical vapor deposition, we investigated the electrochemical behavior of dysprosium(iii) trifluoromethanesulfonate in a custom-made guanidinium-based room-temperature ionic liquid (RTIL). We first examined the electrodeposition of Dy on an Au(111) model electrode. The investigation was carried out by means of cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). The initial stages of metal deposition were followed by in situ scanning tunneling microscopy (STM). CV measurements revealed a large cathodic reduction peak, which corresponds to the growth of monoatomic high islands, based on STM images taken during the initial stages of deposition. XPS identified these deposited islands as dysprosium. A similar reduction peak was also observed on an Nd-Fe-B substrate, and positively identified as deposited Dy using XPS. Finally, we varied the concentration of the Dy precursor, electrolyte flow and temperature during Dy deposition and demonstrated that each of these parameters could be used to increase the thickness of the Dy deposit, suggesting that these parameters could be tuned simultaneously in a temperature-controlled flow cell to enhance the thickness of the Dy layer.

A family of dinuclear lanthanide(III) complexes from the use of a tridentate Schiff base

The use of N-salicylidene-o-aminophenol (H2saph) in 4f-metal chemistry has led to the isolation of seven new isostructural lanthanide(iii) [Ln(III)] complexes. More specifically the Ln(NO3)3·xH2O/H2saph/Et3N (1 : 1 : 1) reaction mixtures in DMF/MeCN gave complexes [Ln2(NO3)2(saph)2(DMF)4] (Ln = Sm (); Eu (); Gd (); Tb (); Dy (); Ho (); Er ()) in good yields (∼65%). The structures of the isomorphous complexes and were solved by single-crystal X-ray crystallography; the other complexes are proposed to be isostructural with and based on elemental analyses, IR spectra and powder XRD patterns. The two Ln(III) atoms in the centrosymmetric molecules of and are doubly bridged by the deprotonated iminophenolato oxygen atoms of two nearly planar η(1):η(1):η(2):μ saph(2-) ligands. The imino nitrogen and five terminal oxygen atoms (the salicylaldiminate, two from one bidentate chelating nitrato group and two from two DMF ligands) complete square antiprismatic coordination at each metal centre. The IR spectra of the complexes are discussed in terms of the coordination modes of the ligands present in the complexes. Solid-state emission studies for all display identical ligand-based photoluminescence. Dc magnetic susceptibility studies in the 2-300 K range reveal the presence of a weak, intramolecular antiferromagnetic exchange interaction (J = -0.19(1) cm(-1) based on the spin Hamiltonian H = -J(ŜGd·ŜGd')) for and probably ferromagnetic exchange interaction within the molecules of and . Ac magnetic susceptibility measurements in zero dc field show temperature- and frequency-dependent out-of-phase signals with two well defined, thermally-activated processes for , suggesting potential single-molecule magnetism character. The Ueff value is 17.4 cm(-1) for the higher temperature process and 16.2 cm(-1) for the lower temperature one. The combination of photoluminescence and single-molecule behaviour in the Dy complex is critically discussed.

Long-lived luminescent soft materials of hexanitratosamarate(III) complexes with orange visible emission

Sm(III)-based ionic liquids incorporating hexanitratosamarate(III) anions were obtained and fully characterized as novel Sm(III)-containing organic complexes. The structure of the ionic liquids was determined by single-crystal X-ray diffraction (1: monoclinic system C2/c space group with cell parameters: a = 19.5624(4) Å, b = 10.11895(18) Å, c = 33.2256(6) Å, β = 101.2912(18)°, Z = 8). The central Sm(III) ion is 12-coordinated by six bidentate nitrate ligands with twelve oxygen donors to form a [Sm(NO3)6](3-) anion. The low melting point, high thermostability and wide liquid range of these ionic liquids were determined in detail. All the complexes 1-5 display orange luminescence, rather than red luminescence as in most Sm(III)-containing organic complexes. Three characteristic monochromatic bands and an intense emission, derived from (4)G5/2→(6)HJ (J = 5/2, 7/2, and 9/2) intraconfigurational f-f transitions, were revealed. All these complexes exhibit long luminescence lifetimes.