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Deep eutectic solvents (DES) with chiral components can function as solvents in circularly polarized light-emitting materials. Deep eutectic solvents were developed with chiral hydrogen bond donors...

Materials that emit circularly polarized light have application in several important industries. Because they show large optical activity and emit sharp visible light transitions, europium complexes are often exploited in applications that require circularly polarized luminescence (CPL). Chiral and coordinating ionic liquids based on prolinate, valinate, and aspartate anions are used to induce CPL from a simple achiral europium triflate salt. The sign of the induced CPL is dependent on the handedness (l vs d) of the amino acid anion. Comparison of the CPL spectra in ionic liquid with proline and valine vs aspartate shows that the number of carboxylate groups in the amino acid anion influences the europium coordination environment. DFT calculations predict a chiral eight-coordinate Eu(Pro)4– structure in the prolinate ionic liquid and a chiral seven- or eight-coordinate Eu(Asp)33– structure in the aspartate ionic liquid.

The luminescence properties of Tb 3+ and Eu 3+ dissolved in ionic liquids are studied. Solutes in this study include simple lanthanide compounds (e.g., EuBr 3 , TbCl 3 ) and lanthanide complexes (e.g., Eu(dpa) 3 3− where dpa = 2,6 pyridine dicarboxylate dianion) dissolved in a 1-butyl-3-methylimidazolium bromide(BMIBr)/water mixture. Emission, excitation, and time-resolved emission measurements are utilized to characterize the spectroscopic properties. It is well established in the literature that the solubility and spectroscopic properties of lanthanides in ionic liquids are highly dependent upon environmental factors including purity, and water content [K. Binnemans, Chemical Reviews (2007); I. Billard, S. Mekki, C. Gaillard, P. Hesemann, C. Mariet, G. Moutiers, A. Labet, J.-C.G. Bunzli, European Journal of Inorganic Chemistry 6 (2004) 1190–1197; S. Samikkanu, K. Mellem, M. Berry, P.S. May, Inorganic Chemistry 46 (2007) 7121–7128]. The water in this ionic liquid system acts as a co-solvent to facilitate solubility of Tb 3+ and Eu 3+ compounds. The observed spectroscopic properties of Eu 3+ and Tb 3+ salts are expectedly impacted by the high water content, but unexpectedly impacted by the BMIBr ionic liquid. However, the spectroscopy of Eu(dpa) 3 3− is unaffected by the presence of BMIBr.

Fluorescence from an excited 5f state of Np(VI) has been observed in the doped impurity system Cs{sub 2}U(Np)O{sub 2}Cl{sub 4}. This is the first intra-5f fluorescence transition that has been detected at room temperature in a condensed-phase system with an actinyl (An(VI)O{sub 2}{sup 2+}) core, and it is a rare example of fluorescence of any kind from non-uranyl ions of this type. The emission originates from an excited state approximately 6890cm{sup -1} above the ground state. Its emission spectrum and fluorescence lifetime at 295K will be discussed. Vibronic structure in the emission spectrum is assigned based on comparison with the detailed analysis of the absorption spectra published by Denning et al.

Trisdipicolinate coordination complexes of europium(III), Eu(dpa)33-, have chiral, three-bladed propeller-like structures with either left-handed or right-handed structural helicity about a 3-fold symmetry axis. The left- and right-handed forms of these structures, labeled here as Λ and Δ, respectively, are structural enantiomers, and they exhibit characteristic circular dichroic absorption and emission properties in their optical excitation and luminescence spectra. In solution media that contain no other chiral species, the Eu(dpa)33- complexes exist as a racemic mixture of interconverting Λ and Δ enantiomeric structures (optical isomers). This racemic mixture of Λ- and Δ-Eu(dpa)33- complexes exhibits no chiroptical properties; but if it is excited with a pulse of circularly polarized light, partially resolved ground- and excited-state populations of Λ and Δ enantiomers are created, and these populations exhibit chiroptical properties reflective of their enantiomeric compositions (defined in terms of en...

Polarized optical absorption and emission measurements are used to locate and assign 95 crystal-field energy levels split out of the 4f( )(8) electronic configuration of Tb(3+) in single crystals of Na(3)[Tb(oda)(3)].2NaClO(4).6H(2)O (where oda denotes an oxydiacetate ligand). The absorption measurements span the 235-490 nm wavelength range, and the emission measurements span the 485-685 nm wavelength range. The combined absorption and emission spectra measurements provide access to the energy-level structures of 46 different 4f( )(8)[SL]J multiplet manifolds of Tb(3+) (all multiplet manifolds with baricenter energies42 400 cm(-)(1) above ground). The site symmetry of the Tb(3+) ions in Na(3)[Tb(oda)(3)].2NaClO(4).6H(2)O is D(3), and the point-group symmetry of the tris-terdentate Tb(oda)(3)(3)(-) coordination complexes is also D(3). The Tb(oda)(3)(3)(-) complexes are chiral, and they exist in just one, fully resolved enantiomeric form in single crystals of Na(3)[Tb(oda)(3)].2NaClO(4).6H(2)O. The crystals exhibit strong chiroptical activity in their absorption and emission spectra, and results obtained from both circularly polarized and linearly polarized optical spectra measurements are used in making transition line assignments. The energy-level data acquired from the spectroscopic measurements are analyzed in terms of a model Hamiltonian that includes consideration of both isotropic and nonisotropic 4f electron/crystal-field interactions, and the interaction parameters derived from this analysis are discussed and then compared with those obtained for other Na(3)[Ln(oda)(3)].2NaClO(4).6H(2)O systems and for Tb(3+) in other crystalline hosts.

Polarized optical absorption and emission measurements are used to locate and assign 60 crystal-field energy levels split out of the 4f8 electronic configuration of Tb3+ in single crystals of Na3[Yb0.95Tb0.05(dpa)3]·NaClO4·10H2O (where dpa ≡ dipicolinate dianion ≡ 2,6-pyridinedicarboxylate). In these crystals, each Tb3+ ion is coordinated to three dipicolinate (dpa) ligands, and the tris-terdentate Tb(dpa)33- chelate structures have trigonal-dihedral (D3) symmetry. The combined optical absorption and emission measurements provide access to the energy-level structures of the 17 lowest-energy 4f8[SL]J multiplet manifolds of Tb3+, and all of these multiplet manifolds are represented among the 60 crystal-field levels that are characterized with respect to both location (energy) and symmetry properties. The energy-level data obtained from experiment are analyzed in terms of a model Hamiltonian that includes consideration of both isotropic and nonisotropic 4f-electron/crystal-field interactions. A parametrized ...

Polarized optical absorption and emission measurements are used to locate and assign 52 crystal-field energy levels split out of the 4f6 electronic configuration of Eu3+ in single crystals of Na3[Yb0.95Eu0.05(dpa)3]·NaClO4·10H2O (where dpa ≡ dipicolinate dianion ≡ 2,6-pyridinedicarboxylate). In these crystals, each Eu3+ is coordinated to three dipicolinate (dpa) ligands, and the tris-terdentate Eu(dpa)33- chelate structures have trigonal-dihedral (D3) symmetry. The combined optical absorption and emission measurements provide access to the energy-level structures of 27 different 4f6[SL]J multiplet manifolds of Eu3+, and 21 of these multiplet manifolds are represented among the 52 crystal-field levels that are characterized with respect to both location (energy) and symmetry properties. The energy-level data obtained from experiment are analyzed in terms of a model Hamiltonian that includes consideration of both isotropic and nonisotropic 4f-electron/crystal-field interactions. A parametrized form of this ...

Optical absorption and emission measurements are used to locate and assign 152 crystal-field energy levels split out of the 4f{sup 9} electronic configuration of Dy{sup 3+} in Na{sub 3}[Dy(oda){sub 3}]{center_dot}2NaClO{sub 4}{center_dot}6H{sub 2}O (where oda denotes an oxydiacetate ligand). The absorption measurements span the 230-1800 nm wavelength range, and they encompass all optical transitions that may occur between the {sup 6}H{sub 15/2} ground multiplet and 63 different excited multiplet manifolds of the 4f{sup 9}(Dy{sup 3+}) electronic configuration.

The optical absorption, emission, FT Raman, one-photon excitation, two-photon excitation, and luminescence lifetime measurements are reported for UO(2)Cl(4)(2)(-) in 40:60 AlCl(3)-EMIC (where EMIC identical with 1-ethyl-3-methylimidazolium chloride), a room-temperature ionic liquid. Comparison of the spectra with previous results from single crystals containing UO(2)Cl(4)(2)(-) allowed the characterization of four ground-state vibrational frequencies, two excited-state vibrational frequencies, and the location of eight electronic excited-state energy levels. The vibrational frequencies and electronic energy levels are found to be consistent with the UO(2)Cl(4)(2)(-) ion. Comparison of the one-photon and two-photon excitation spectra, and the relative intensities of the transitions in the emission spectrum indicate that the center of symmetry is perturbed by an interaction with the solvent.