Lanthanide Loading of Luminescent Multi-Tridentate Polymers under Thermodynamic Control

Babel, Lucille; Hoang, Thi Nhu Y; Nozary, Homayoun; Salamanca, Jasmina; Guénée, Laure; Piguet, Claude

doi:10.1021/ic4030525

Cited by 30 publications

(62 citation statements)

References 83 publications

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“…Application of the site‐binding model decomposes into a contribution from the conditional intrinsic affinities

f_{aff, cond}^{Ln, 𝐋𝐤}

of the tridentate site for the entering [Ln(hfac) 3 ] metal carrier and an intersite cooperativity factor

u_{1 - 2}^{Ln, Ln} = e x p (- Δ E_{1 - 2}^{Ln, Ln} / R T)

operating in the saturated complexes [ Lk Ln 2 (hfac) 6 ] [right part of Eqs. (3) and (4)] . Since no significant dissociation of the metallic salts occurs in dichloromethane at sub‐millimolar concentrations used for NMR titrations, [Ln(hfac) 3 (dig)] exists as a single species in solution, the concentration of which is written as

([], Ln)

in Equations (1)–(4), and for the rest of this work.…”

Section: Resultsmentioning

confidence: 99%

“…(3) and (4)] . Since no significant dissociation of the metallic salts occurs in dichloromethane at sub‐millimolar concentrations used for NMR titrations, [Ln(hfac) 3 (dig)] exists as a single species in solution, the concentration of which is written as

([], Ln)

in Equations (1)–(4), and for the rest of this work. For each [ Lk ] tot /[Ln] tot stoichiometric mixture under investigation, the 1 H and 19 F NMR spectra recorded under thermodynamic equilibrium showed no dynamic exchange process on the NMR time scale (Tables S1 and S2 in the Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

“…(5)], from which the concentration of free metal

[Ln] = {([], Ln)}_{tot} - 2 θ_{Ln} {([], 𝐋𝐤)}_{tot}

is easily deduced. The plots of

θ_{Ln}^{\exp}

in function of log([Ln]), known as the binding isotherms (Figure ), are ideally suited for the estimation of

f_{aff, cond}^{Ln, 𝐋𝐤}

and

u_{1 - 2}^{Ln, Ln}

by using nonlinear least‐square fits of

θ_{Ln}^{calcd}

defined in Equation (6) (Table S3 in the Supporting Information) ,

θ_{Ln}^{\exp} = \frac{(〈〉, m)}{N} = \frac{1}{2} \frac{{|Ln|}_{bound}}{{|𝐋𝐤|}_{tot}} = \frac{1}{2} \cdot \frac{I_{Ln 𝐋 𝐤}^{normalH} + 2 (I_{{Ln}_{2} 𝐋 𝐤}^{H})}{I_{𝐋 𝐤}^{normalH} + I_{Ln 𝐋 𝐤}^{normalH} + I_{{Ln}_{2} 𝐋 𝐤}^{normalH}} = \frac{I_{Ln 𝐋 𝐤}^{normalF} + I_{{Ln}_{2} 𝐋 𝐤}^{normalF}}{I_{Ln}^{normalF} + I_{Ln 𝐋 𝐤}^{normalF} + I_{{Ln}_{2} 𝐋 𝐤}^{normalF}} \cdot \frac{{[Ln]}_{tot}}{2 {([], 𝐋 𝐤)}_{tot}}

θ_{Ln}^{calcd} = \frac{1}{2} \frac{{|Ln|}_{bound}}{{|𝐋𝐤|}_{tot}} = [Ln 𝐋 𝐤] + 2 [<...>]

…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, positive cooperativity, characterized by

Δ E_{1 - 2}^{M, normalM}

≪0, results in the formation of clusters of occupied sites for θ M =0.5 (Figure b, left). The validity of these predictions was recently explored for the design of tunable materials, in which the linear multi‐tridentate polymers L1 N ( N =10, 12, 20, 31 is the number of available binding sites, Figure a) were loaded with luminescent lanthanide β‐diketonates complexes [Ln(hfac) 3 ] (Ln=La, Eu, Y; hfac=hexafluoroacetylacetone) . Whereas the slightly cooperative (1.5≤

u_{1 - 2}^{Ln, Ln}

≤1.8) nearest‐neighbor intermetallic interactions accompanying the multistep binding processes leading to [ L1 N (Ln(hfac) 3 ) m ] do not significantly vary with the polymer length N (red triangles in Figure b), the intrinsic affinity for a specific tridentate binding site drastically decreases by one order of magnitude in going from the monomeric ligand L0 ( N =0) to the polymers L1 N with N ≥10 (black diamonds in Figure b)…”

Section: Introductionmentioning

confidence: 99%

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Looking for the Origin of Allosteric Cooperativity in Metallopolymers

Babel

Hoang

Guénée

et al. 2016

Chemistry A European J

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The basic concept of allosteric cooperativity used in biology, chemistry and physics states that any change in the intermolecular host-guest interactions operating in multisite receptors can be assigned to intersite interactions. Using lanthanide metals as guests and linear multi-tridentate linear oligomers of variable lengths and geometries as hosts, this work shows that the quantitative modeling of metal loadings requires the consideration of a novel phenomenon originating from solvation processes. It stepwise modulates the intrinsic affinity of each isolated site in multisite receptors, and this without resorting to allosteric cooperativity. An easy-to-handle additive model predicts a negative power law dependence of the intrinsic affinity on the length of the linear metallopolymer. Applied to lanthanidopolymers, the latter common analysis overestimates cooperativity factors by more than two orders of magnitude.

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“…Application of the site‐binding model decomposes into a contribution from the conditional intrinsic affinities

f_{aff, cond}^{Ln, 𝐋𝐤}

of the tridentate site for the entering [Ln(hfac) 3 ] metal carrier and an intersite cooperativity factor

u_{1 - 2}^{Ln, Ln} = e x p (- Δ E_{1 - 2}^{Ln, Ln} / R T)

([], Ln)

in Equations (1)–(4), and for the rest of this work.…”

Section: Resultsmentioning

confidence: 99%

([], Ln)

Section: Resultsmentioning

confidence: 99%

“…(5)], from which the concentration of free metal

[Ln] = {([], Ln)}_{tot} - 2 θ_{Ln} {([], 𝐋𝐤)}_{tot}

is easily deduced. The plots of

θ_{Ln}^{\exp}

in function of log([Ln]), known as the binding isotherms (Figure ), are ideally suited for the estimation of

f_{aff, cond}^{Ln, 𝐋𝐤}

and

u_{1 - 2}^{Ln, Ln}

by using nonlinear least‐square fits of

θ_{Ln}^{calcd}

defined in Equation (6) (Table S3 in the Supporting Information) ,

θ_{Ln}^{\exp} = \frac{(〈〉, m)}{N} = \frac{1}{2} \frac{{|Ln|}_{bound}}{{|𝐋𝐤|}_{tot}} = \frac{1}{2} \cdot \frac{I_{Ln 𝐋 𝐤}^{normalH} + 2 (I_{{Ln}_{2} 𝐋 𝐤}^{H})}{I_{𝐋 𝐤}^{normalH} + I_{Ln 𝐋 𝐤}^{normalH} + I_{{Ln}_{2} 𝐋 𝐤}^{normalH}} = \frac{I_{Ln 𝐋 𝐤}^{normalF} + I_{{Ln}_{2} 𝐋 𝐤}^{normalF}}{I_{Ln}^{normalF} + I_{Ln 𝐋 𝐤}^{normalF} + I_{{Ln}_{2} 𝐋 𝐤}^{normalF}} \cdot \frac{{[Ln]}_{tot}}{2 {([], 𝐋 𝐤)}_{tot}}

θ_{Ln}^{calcd} = \frac{1}{2} \frac{{|Ln|}_{bound}}{{|𝐋𝐤|}_{tot}} = [Ln 𝐋 𝐤] + 2 [<...>]

…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, positive cooperativity, characterized by

Δ E_{1 - 2}^{M, normalM}

u_{1 - 2}^{Ln, Ln}

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Looking for the Origin of Allosteric Cooperativity in Metallopolymers

Babel

Hoang

Guénée

et al. 2016

Chemistry A European J

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“…Several studies of these ligands report the criteria for the formation of stable luminescent complexes by binding N‐heterocyclic tridentate aromatic ligands to Ln(hfac) 3 by cascade complexation (hfac = hexafluoroacetylacetonate) . More recently, N‐heterocyclic tridentate ligands have been used as the building units of multi‐tridentate polymers for loading Ln(hfac) 3 . In pursuit of furthering our understanding of the luminescence properties of lanthanide complexes,, we have designed and synthesized a set of europium complexes based on dipyrazolyltriazine and trifluoro(thenoyl)acetone (tta) as the sensitizing ligands (Scheme ) in the light of earlier studies .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, Photoluminescence, and Electroluminescence of Four Europium Complexes: Fabrication of Pure Red Organic Light‐Emitting Diodes from Europium Complexes

et al. 2017

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Four new europium complexes were prepared by treating europium(III) trifluoro(thenoyl)acetonate trihydrate with new tridentate ligands, based on dipyrazolyltriazine and utilized as emitting materials in electroluminescent devices. The complexes were characterized by elemental analysis, FTIR spectroscopy, UV/Vis spectrophotometry, and 1H NMR spectroscopy. The coordinated ligands serve as light‐harvesting chromophores in the complexes, with absorption maxima in the range 334–402 nm [ε = (8.9–81.4) × 103 m–1 cm–1]. The ligands efficiently sensitize europium luminescence, with maximum quantum‐yield (QLEu) and observed lifetime (τobs) values of 34 % and 600 µs in the solid state and 35 % and 528 µs in toluene, respectively. The radiative lifetimes of Eu (5D0) are in the range 1170–1281 µs and the ligand‐to‐metal energy‐transfer efficiency (ηsens) is in the range 71–92 % for those complexes in the solid state and in the range 68–97 % for those in solution. Additionally, organic light‐emitting diodes (OLEDs), which exhibited pure red emission, were fabricated with europium(III) complexes. It is shown that by modifying the [Eu(tta)3·3H2O] molecule with ancillary ligands, one can tune and control its electroluminescence spectra, along with its electrical properties, such as the current/voltage characteristics of OLED devices based on [Eu(tta)3(L)]. The best OLED presented a maximum luminance of 3156 cd/m2 and a maximum efficiency of 0.7 cd/A at an applied voltage of 8 V.

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Solution‐State Cooperative Luminescence Upconversion in Molecular Ytterbium Dimers

Soro

Knighton

Avecilla

et al. 2022

Advanced Optical Materials

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anti-Stokes emission, UC is a process of choice for bio-analytical applications, removing spurious signals originating from autofluorescence of the samples and light scattering. Consequently, UC has found many applications such as in microscopy and photodynamic therapy, [2] remote cellular activation, [3] or bioassays. [4,5] However, these processes are typically observed in solid-state materials [6] or nanoparticles, [7] but a seminal example of energy transfer UC (ETU) at the molecular scale was reported by Piguet and co-workers in 2011, which consisted of a triply stranded Cr III -Er III -Cr III helicate. [8,9] In the subsequent years this has been expanded to encompass a range of discrete upconverting systems, operating by excited state absorption (ESA), [10][11][12] energy transfer UC, or cooperative sensitizaton (CS). [15][16][17][18] At the molecular scale, much attention must be paid to minimize quenching due to the increased prevalence of nonradiative de-excitation processes from molecules in solution, primarily through OH, NH, and CH oscillators in the first or second coordination sphere. [20][21][22] This is achieved by using sterically encumbering ligand systems, [23] deuteration of the ligand scaffold, [16] or using perdeuterated solvents. [16,24,25] One key impediment in the development of new molecular UC devices is the typical requirement to prepare heterometallic polyads, as is the case with CS systems comprising two or more Yb III sensitizers around Tb III or Ru II acceptors (Figure 1a). [17,26] This approach, despite its effectiveness, is onerous due to the similar chemical reactivity between lanthanides, [27,28] as is the case for mixed Yb/Tb systems, which constrains the synthetic accessibility. [15,16] Inspired by the pioneering work by Auzel [29] on solid-state materials, [30,31] we reported the first example of solution-state molecular cooperative luminescence (CL) using a Yb 9 cluster. [32] This entails double excitation of two proximate Yb III ions at 980 nm which produces emission from a virtual excited state at 503 nm via a two-photon process (Figure 1b). While it is a key tenet of UC processes that the efficiency of UC is improved using more donor ions, there also remains the possibility of concentration quenching, which has been observed in nanoparticles. [33,34] Furthermore, the two-photon power dependence of the UC observed in homo-nonanuclear Yb 9 clusters supports the accepted mechanism of the requirement of only two proximate Yb III ions. Conclusive confirmation of this dinuclear mechanism can only occur through removal of the extraneous Yb III donors to its fundamental form in a dimeric Yb 2 system (lex parsimoniae). This strategy is not feasible in either Two homometallic ytterbium dimers are prepared and their solution-state photoluminescence and upconversion properties are investigated. Both complexes exhibit two-photon cooperative luminescence upconversion in the visible region (λ em ≈ 510 nm) upon excitation into the near-infrared Yb 2 F 5/2 ← 2 F 7/2 absorption band at 98...

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Lanthanide Loading of Luminescent Multi-Tridentate Polymers under Thermodynamic Control

Cited by 30 publications

References 83 publications

Looking for the Origin of Allosteric Cooperativity in Metallopolymers

Looking for the Origin of Allosteric Cooperativity in Metallopolymers

Synthesis, Structure, Photoluminescence, and Electroluminescence of Four Europium Complexes: Fabrication of Pure Red Organic Light‐Emitting Diodes from Europium Complexes

Solution‐State Cooperative Luminescence Upconversion in Molecular Ytterbium Dimers

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