scholarly journals Striking Solvent Dependence of Total Emission and Circularly Polarised Luminescence in Coordinatively Saturated Chiral Europium Complexes: Solvation Significantly Perturbs the Ligand Field

2021 ◽  
Author(s):  
David Parker ◽  
Robert Pal ◽  
Jack Fradgley ◽  
Andrew T. Frawley
Keyword(s):  
Ligand Field ◽  
Total Emission ◽  
Europium Complexes ◽  
Solvent Dependence ◽  
Ligand Fields

Examination of total emission and circularly polarised luminescence (CPL) spectra of three 9-coordinate Eu(III) complexes with well-defined speciation shows that the ligand fields of these C3 symmetric complexes are extremely...

scholarly journals Outer-sphere effects on ligand-field excited-state dynamics: solvent dependence of high-spin to low-spin conversion in [Fe(bpy)3]2+

2020 ◽  
Vol 11 (20) ◽  
pp. 5191-5204 ◽  
Author(s):  
Jennifer N. Miller ◽  
James K. McCusker
Keyword(s):  
Excited State ◽  
Reorganization Energy ◽  
Outer Sphere ◽  
Ligand Field ◽  
Spin Conversion ◽  
Energy Effect ◽  
Time Resolved ◽  
Excited State Dynamics ◽  
State Recovery ◽  
Solvent Dependence

Time-resolved spectroscopic measurements of ground-state recovery for [Fe(bpy)3]2+ reveal that the solvent can induce an outer-sphere reorganization energy effect on excited-state dynamics involving metal-centered ligand-field electronic states.

Ligand field effects on the ground and excited states of reactive FeO2+ species

2018 ◽  
Vol 20 (45) ◽  
pp. 28786-28795 ◽  
Author(s):  
Justin K. Kirkland ◽  
Shahriar N. Khan ◽  
Bryan Casale ◽  
Evangelos Miliordos ◽  
Konstantinos D. Vogiatzis
Keyword(s):  
Iron Oxide ◽  
Quantum Chemical Calculations ◽  
Excited States ◽  
Quantum Chemical ◽  
Ligand Field ◽  
Reactive Iron ◽  
Field Effects ◽  
Ligand Fields

Multiconfigurational quantum chemical calculations on bare and representative ligated iron oxide dicationic species suggest that weak ligand fields promote more reactive channels, whereas strong ligand fields stabilize the less reactive iron-oxo structure.

The d2 and d8 Noncubic Ligand Field Spectrum. I. The Complete Theory of Quadrate, Trigonal, and Cylindrical Ligand Fields

1972 ◽  
Vol 27 (12) ◽  
pp. 1820-1860 ◽  
Author(s):  
Jayarama Perumareddi
Keyword(s):  
Cylindrical Symmetry ◽  
Complete Theory ◽  
Ligand Field ◽  
Spin Orbit ◽  
Planar Limit ◽  
Unitary Transformations ◽  
Cubic Fields ◽  
Electronic Configurations ◽  
Tetrahedral Complexes ◽  
Ligand Fields

AbstractThe complete theory of Liehr and Ballhausen for d2 and d8 electronic configurations immersed in cubic fields has been extended to include noncubic ligand fields of quadrate, trigonal, and cylindrical symmetry. The complete set of symmetry adapted eigenvectors for the three symmetries have been derived in various coupling schemes in which the spin-orbit interaction, electron cor-relation, and ligand field in turn are varied from minor to dominant perturbations. The cor-responding energy matrices as a function of the parameters of the ligand field, electron correlation, and spin-orbit constant have been constructed in all the representations. Unitary transformations connecting different formalisms were obtained. The energy matrices have been solved for representative sets of parametric values and energy diagrams have been plotted in all the symmetries as well as in the square planar limit of the quadrate crystalline field. The secular determinants, the eigenfunctions, the energy diagrams, and the unitary transformations presented here are extremely useful in the study of the various aspects of spectroscopic, magnetic, and other properties of appropriate systems. The theory is applicable to quadrately distorted or substituted, trigonally distorted or substituted, octahedral and tetrahedral complexes and to compounds of cylindrical symmetry of d2 and d8 electronic configurations.

Enhancing the barrier height for Yb(iii) single-ion magnets by modulating axial ligand fields

2020 ◽  
Vol 56 (79) ◽  
pp. 11879-11882 ◽  
Author(s):  
Aditya Borah ◽  
Sourav Dey ◽  
Sandeep K. Gupta ◽  
Mrinalini G. Walawalkar ◽  
Gopalan Rajaraman ◽  
...  
Keyword(s):  
Barrier Height ◽  
Axial Ligand ◽  
Ligand Field ◽  
Magnetic Reversal ◽  
Ligand Fields

Progressive weakening of the axial ligand field, by keeping the equatorial field constant, enhances the barrier height for magnetic reversal in six-coordinate pseudo-octahedral Yb(iiii) single ion magnets.

scholarly journals Multiligand Europium Complexes Incorporated Polyvinylpyrrolidone for Enhanced Solar Cell

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Zhimin Yu ◽  
Jing Guo ◽  
Desheng Li ◽  
Hai Lin
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Quantum Yield ◽  
Fluorescence Emission ◽  
Total Emission ◽  
Europium Complexes ◽  
Orange Fluorescence ◽  
Photon Conversion ◽  
Uv Visible ◽  
Reddish Orange

Intense reddish-orange fluorescence of Eu3+ is observed in multiligand europium complexes Eu(BA)(TTA)2 and Eu(BA)(TTA)2Phen doped polyvinylpyrrolidone (PVP). Under 367 nm UVA-LED pumping with 708.5 μW, the net emission powers are as high as 204.8 and 243.2 μW, and the total emission photon numbers are derived to be 635.9 × 1012 and 754.9 × 1012 cps for Eu(BA)(TTA)2 and Eu(BA)(TTA)2Phen doped PVP thin films, respectively. It is incredible that the quantum yield (QY) is up to 57.87% in the former; furthermore, as the introduction of Phen, the QY of Eu3+ is increased to 62.03%, verifying the effectiveness of multiligands in photon conversion. Conclusive photon quantification and efficient fluorescence emission reveal the potential of europium complexes/PVP as UV-visible conversion layers for enhanced solar cells.

Slow relaxations of Dy(III) single-ion magnets dominated by simultaneous binding of chelating ligands in low-symmetry ligand-fields

2022 ◽  
Author(s):  
Hui-Ming Dong ◽  
Zhong-Yi Liu ◽  
Hui-Min Tang ◽  
En-Cui Yang ◽  
Yi-Quan Zhang ◽  
...  
Keyword(s):  
Electronic Effect ◽  
Ligand Field ◽  
Chelating Ligands ◽  
Spin Reversal ◽  
Slow Relaxations ◽  
Ligand Fields ◽  
Low Symmetry

Electronic effect and geometry distortion of low-symmetry ligand-field on anisotropy barrier (Ueff) of spin reversal have been compared in three Dy(III) single-ion magnets through simultaneous binding of chelating ligands. The...

Fluorescence Spectra of Homogeneous and Mixed Europium Complexes

1968 ◽  
Vol 22 (5) ◽  
pp. 513-519 ◽  
Author(s):  
Nicolae Filipescu ◽  
K. Moorjani ◽  
N. McAvoy ◽  
S. Bjorklund ◽  
C. R. Hurt ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Transition Probabilities ◽  
Emission Spectra ◽  
Ligand Field ◽  
Bidentate Ligands ◽  
Molecular Configuration ◽  
Europium Complexes ◽  
The Individual ◽  
Ligand Field Parameters ◽  
Ground Multiplet

High-resolution emission spectra of several europium complexes with β-diketones, dipyridyl, and phenanthroline have been examined at 77°K in microcrystals. The Stark splitting of the 7 F levels in the ground multiplet and the relative intensities of the individual 5 D0→7 F transitions can be used for theoretical correlation with the ligand field parameters, transition probabilities, molecular structure, and Eu-ligand bonding. The fluorescence spectra of the bis-aqua, tris, tris-aqua, tetrakis, and mixed chelates with the bidentate ligands are discussed in relation to molecular configuration.

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