NMR and luminescence experiments reveal the structure and symmetry adaptation of a europium ionic liquid to solvent polarity

Castro, Gerson P.; Melo, Lizandra L. L. S.; Hallwass, Fernando; Gonçalves, Simone M. C.; Simas, Alfredo M.

doi:10.1039/d1dt01050f

Cited by 4 publications

(1 citation statement)

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“…Apart from a crystallographic determined geometry, the actual detailed three-dimensional structure of a lanthanoid complex in the solid state is usually unknown. And if the lanthanoid complex is in solution, there is no guarantee that its shape and stereoisomer will be the same as in a crystal 19 . Actually, what is usually known about a complex is its molecular formula, the formulas of the ligands, and, perhaps, due to some additional experimental evidence, the point group symmetry of the coordination polyhedron and/or its presumed shape.…”

Section: Introductionmentioning

confidence: 99%

The complex build algorithm to set up starting structures of lanthanoid complexes with stereochemical control for molecular modeling

Munguba

Urquiza-Carvalho

Silva

et al. 2021

Sci Rep

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When handling metallic centers of higher coordination numbers, one is commonly deluded with the presumption that any assembled metal complex geometry (including a crystallographic one) is good enough as a starting structure for computational chemistry calculations; all oblivious to the fact that such a structure is nothing short of just one out of several, sometimes dozens, or even thousands of other stereoisomers. Moreover, coordination chirality, so frequently present in complexes of higher coordination numbers, is another often overlooked property, rarely recognized as such. The Complex Build algorithm advanced in this article has been designed with the purpose of generating starting structures for molecular modeling calculations with full stereochemical control, including stereoisomer complete identification and coordination chirality recognition. Besides being in the chosen correct stereochemistry, the ligands are positioned by the Complex Build algorithm in a very unobstructed and unclogged manner, so that their degrees of freedom do not hinder or even choke one another, something that would otherwise tend to lead to negative force constants after further geometry optimizations by more advanced computational model chemistries. The Complex Build algorithm has been conceived for any metallic center, but at present is targeting primarily lanthanoids whose coordination numbers range mostly from 5 to 12 and often lead to a combinatorial explosion of stereoisomers.

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Section: Introductionmentioning

confidence: 99%

The complex build algorithm to set up starting structures of lanthanoid complexes with stereochemical control for molecular modeling

Munguba

Urquiza-Carvalho

Silva

et al. 2021

Sci Rep

Self Cite

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Microwave Synthesis and Luminescence Efficiencies in Mixed‐Ligand Europium Complexes

Oliveira,

Castro,

Gonçalves

et al. 2024

Chemistry An Asian Journal

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The microwave‐assisted methodology is now extended and fine‐tuned for the synthesis of mixed‐ligand europium complexes with an average reaction time of 12 min. Overall, 14 different complexes were synthesized to improve luminescence using our previously proposed strategy to boost luminescence through ligand diversification, specifically by applying it to quaternary europium complexes with at least one DBM (1,3‐diphenylpropane‐1,3‐dionate) ligand. DBM is a strong absorbant of UV radiation that can dissipate energy through nonradiative channels; thus, it is a useful molecular scaffold for sunblockers and cosmetics. Accordingly, the following luminescent tetrakis and quaternary complexes were prepared: K[Eu(DBM)4], K[Eu(β)4], K[Eu(DBM)3(β)], K[Eu(DBM)2(β)2], K[Eu(DBM)2(β)(β’)], and the fully mixed complex K[Eu(DBM)(BTFA)(TTA)(HFAC)], where β can be either BTFA (4,4,4‐trifluoro‐1‐phenylbutane‐1,3‐dionate), TTA (4,4,4‐trifluoro‐1‐(2‐thienyl)butane‐1,3‐dionate), or HFAC (1,1,1,5,5,5‐hexafluoropentane‐2,4‐dionate). For all the complexes, luminescence experiments were performed in chloroform and acetone solutions. Our findings confirm that mixed‐ligand complexes exhibit superior quantum efficiencies compared to the average of their homoleptic counterparts. The presence of DBM in the complexes tends to dramatically increase the nonradiative decay rates of the solutions. Finally, we present formulae that provide a detailed understanding of the distinctive roles of each ligand and their relevant interactions in luminescence.

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Luminescence properties of lanthanide tetrakis complexes as molecular light emitters

Costa,

Blois,

Paolini

et al. 2024

Coordination Chemistry Reviews

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NMR and luminescence experiments reveal the structure and symmetry adaptation of a europium ionic liquid to solvent polarity

Abstract: By combining NMR data (nuclear Overhauser effect and pseudocontact shifts) with luminescence measurements, we uncover how the structure of an anionic europium complex adapts to different solvent polarities as a...

Cited by 4 publications

References 51 publications

The complex build algorithm to set up starting structures of lanthanoid complexes with stereochemical control for molecular modeling

The complex build algorithm to set up starting structures of lanthanoid complexes with stereochemical control for molecular modeling

Microwave Synthesis and Luminescence Efficiencies in Mixed‐Ligand Europium Complexes

Luminescence properties of lanthanide tetrakis complexes as molecular light emitters

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