Luminescence, chiroptical, magnetic and<i>ab initio</i>crystal-field characterizations of an enantiopure helicoidal Yb(<scp>iii</scp>) complex

Gendron, Frédéric; Pietro, Sebastiano Di; Galán, Laura Abad; Riobé, François; Placide, Virginie; Guy, Laure; Zinna, Francesco; Bari, Lorenzo Di; Bensalah‐Ledoux, Amina; Guyot, Y.; Pilet, Guillaume; Pointillart, Fabrice; Baguenard, B.; Guy, S.; Cador, Olivier; Maury, Olivier; Guennic, Boris Le

doi:10.1039/d0qi01194k

Cited by 49 publications

(76 citation statements)

References 85 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…400 cm -1 , close to that of threefold symmetry complexes reported in the literature (LFS max in the range 340-370 cm -1 ). 34,59,[69][70][71] The slightly higher value confirms the distortion from the threefold symmetry already mentioned for EuL 1 . The absence of singlet oxygen emission at 1270 nm further indicates a preferable intramolecular energy transfer from the triplet of the ligand to the 7 F5/2 of the central Yb 3+ ion above an intermolecular energy transfer to the molecule of O2.…”

Section: A 2 φ δ = 60%supporting

confidence: 62%

Tuning the excited state properties of [2.2]paracyclophane-based antennas to ensure efficient sensitization of lanthanide ions or singlet oxygen generation.

Galán

Roux

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

The multi-step synthesis of original antennas incorporating substituted [2.2]paracyclophane (pCp) moieties in the -conjugated skeleton is described. These antennas, functionalized with electron an donor alkoxy fragment (A 1 ) or with a fused coumarin derivative (A 2 ) are incorporated in a triazacyclonane macrocyclic ligand L 1 or L 2 , respectively for the design of Eu(III), Yb(III) and Gd(III) complexes. A combined photophysical/theoretical study reveals that A 1 presents a charge transfer character via the through-space paracyclophane conjugation, whereas A 2 presents only local excited states centered on the coumarin-paracyclophane moiety, strongly favoring triplet state population via intersystem crossing. The resulting complexes EuL 1 and YbL 2 are fully emissive in the red and near infrared, respectively whereas the GdL 2 complex acts as photosensitizer for the generation of singlet oxygen.

show abstract

Section: A 2 φ δ = 60%supporting

confidence: 62%

Tuning the excited state properties of [2.2]paracyclophane-based antennas to ensure efficient sensitization of lanthanide ions or singlet oxygen generation.

Galán

Roux

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Solution NMR is a powerful tool for the structural analysis of paramagnetic lanthanide complexes [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]: the paramagnetism of a lanthanide trivalent ion influences both the chemical shift and linewidth of the resonance of a nucleus close in space. In particular, the paramagnetic contribution (in sign and magnitude) to the chemical shift has dipolar origin, and it correlates with the relative position (in polar coordinates) of the nucleus with respect to the lanthanide ion and the major symmetry axis of the system, through the McConnel-Robertson equation [ 39 ] (Equation (1), valid for C 3 systems or higher).…”

Section: Resultsmentioning

confidence: 99%

New Coumarin Dipicolinate Europium Complexes with a Rich Chemical Speciation and Tunable Luminescence

et al. 2021

Self Cite

View full text Add to dashboard Cite

Europium (III) luminescent chelates possess intrinsic photophysical properties that are extremely useful in a wide range of applications. The lack of examples of coumarin-based lanthanide complexes is mainly due to poor photo-sensitization attempts. However, with the appeal of using such a versatile scaffold as antenna, especially in the development of responsive molecular probes, it is worth the effort to research new structural motifs. In this work, we present a series of two new tris coumarin-dipicolinate europium (III) complexes, specifically tailored to be either a mono or a dual emitter, tuning their properties with a simple chemical modification. We also encountered a rich chemical speciation in solution, studied in detail by means of paramagnetic NMR and emission spectroscopy.

show abstract

“…An interesting feature of the MChD spectra is the alternation of its sign with the nature of the excited Kramers doublets. The similitude between the shape of the MChD and the rare NCD spectra reported for chiral Yb III complexes, 21,24 highlights that to fully unravel the link between these phenomena, MChD, NCD and MCD measurements in the same experimental conditions are mandatory, although they remain technically challenging. The asymmetric factor gMChD (see SI), which evaluate the portion of absorption or emission that is affected by the magnetic field, is ca.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Helicene-Based Ligands Enable Strong Magneto-Chiral Dichroism in a Chiral Ytterbium Complex

et al. 2021

Self Cite

View full text Add to dashboard Cite

Here we report the first experimental observation of magneto-chiral dichroism (MChD) detected through light absorption in an enantiopure lanthanide complex. The P and M enantiomers of [YbIII((X)-L)(hfac)3] (X = P, M; L = 3-(2-pyridyl)-4-aza[6]-helicene; hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate), where the chirality is held by the helicene-based ligand, were studied in the near-infrared spectral window. When irradiated with unpolarized light in a magnetic field, these chiral complexes exhibit a strong MChD signal (g MChD ca. 0.12 T–1) associated with the 2F5/2 ← 2F7/2 electronic transition of YbIII. The low temperature absorption and MChD spectra reveal a fine structure associated with crystal field splitting and vibronic coupling. The temperature dependence of the main dichroic signal detected up to 150 K allowed, for the first time, the disentanglement of the two main microscopic contributions to the dichroic signal predicted by the MChD theory. These findings pave the way toward probing MChD in chiral lanthanide-based single-molecule magnets.

show abstract

Luminescence, chiroptical, magnetic andab initiocrystal-field characterizations of an enantiopure helicoidal Yb(iii) complex

Abstract: The electronic structure of a chiral Yb(III)-based complex is fully determined by taking advantage of experimental magnetic, luminescence, and chiroptical (NIR-ECD and CPL) characterizations in combination with ab-initio wavefunction calculations....

Cited by 49 publications

References 85 publications

Tuning the excited state properties of [2.2]paracyclophane-based antennas to ensure efficient sensitization of lanthanide ions or singlet oxygen generation.

Tuning the excited state properties of [2.2]paracyclophane-based antennas to ensure efficient sensitization of lanthanide ions or singlet oxygen generation.

New Coumarin Dipicolinate Europium Complexes with a Rich Chemical Speciation and Tunable Luminescence

Helicene-Based Ligands Enable Strong Magneto-Chiral Dichroism in a Chiral Ytterbium Complex

Contact Info

Product

Resources

About