Synthesis and Spectroscopic Study of d–f Hybrid Lanthanide Complexes Derived from triazolylDO3A

Tropiano, Manuel; Record, Christopher J; Morris, Eleanor; Hardeep, S.; Allain, Clémence; Faulkner, Stephen

doi:10.1021/om3003569

Cited by 47 publications

(17 citation statements)

References 24 publications

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“…[173] A similar strategy has been employed in utilising a pendant 'click' derived triazole in stabilising Ln(III) coordination through interaction with the N(3) position whilst simultaneously axially coordinating through N(1) to a bipyridine-containing Re(CO)3 complex (144 to 146). [174] In this assembly, the d-block complex serves as a light absorbing antenna, sensitising lanthanide luminescence through Dexter energy transfer to metal centres including Yb(III) and Nd(III). DO3A-based Tb(III) complex 147 is brightly emissive but suffers quenching on binding a Cu(II) ion to the dipicolylamine receptor.…”

Section: Lanthanide Complexesmentioning

confidence: 99%

Photophysics and photochemistry of 1,2,3-triazole-based complexes

Scattergood

Sinopoli

Elliott

2017

Coordination Chemistry Reviews

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The copper-catalysed cycloaddition of alkynes and azides to form 1,2,3-triazoles has emerged as a powerful tool in ligand design and the synthesis of novel transition metal complexes. In this review we focus on the photophysical properties of metal complexes bearing 1,2,3-triazole-based ligands with a particular emphasis on those of d 6 metals including rhenium(I), iron(II), ruthenium(II), osmium(II) and iridium(III). We also highlight key examples of triazole complexes of platinum(II) and palladium(II) as well as the lanthanides and coinage metals. 1. Introduction 2. Photophysical properties of d 6 metal triazole-based complexes 2.1 Rhenium(I) complexes 2.2 Iridium(III) complexes 2.3 Ruthenium(II) complexes 2.4 Iron(II) complexes 2.5 Osmium(II) complexes 2.6 Photochemistry of 1,2,3-triazole-based d 6 metal complexes 3. Platinum(II) and palladium(II) complexes 4. Coinage metal complexes 5. Lanthanide complexes 6. Triazole-based sensors for metal ions 7. Conclusions & outlook.

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Section: Lanthanide Complexesmentioning

confidence: 99%

Photophysics and photochemistry of 1,2,3-triazole-based complexes

Scattergood

Sinopoli

Elliott

2017

Coordination Chemistry Reviews

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“…This reaction has proven highly efficient for preparing larger architectures using kinetically stable lanthanide complexes as molecular building blocks. 20,37,44,[53][54][55][56][57][58] Amino-functionalized 2-methyl-18-crown-6 and 18-benzocrown-6 binding pockets were readily converted to azides using an azide transfer reagent [59][60] The azides were subsequently coupled to lanthanide complexes of 1-propagyl-1,4,7,10-tetraazacyclododecane-4,7,10-triacetic acid (Ln.propargoyl-DO3A, Ln.L 1 ) in a CuAAC "click" reaction. Three different lanthanide complexes-with europium(III), terbium(III) and ytterbium(III)-were coupled to the benzocrown (Ln.L 2 ), while only the europium and terbium complex were prepared from the aliphatic crown ether (Ln.L 3 ).…”

Section: K +mentioning

confidence: 99%

Kinetically Inert Lanthanide Complexes as Reporter Groups for Binding of Potassium by 18-crown-6

et al. 2016

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The barcode-like spectrum of lanthanide-centered emission has been used in imaging and to make responsive luminescent reporters. The intensities and the shapes of each line in the luminescence spectrum can also report on the coordination environment of the lanthanide ion. Here, we used lanthanide-centered emission to report on the binding of potassium in an 18-crown-6 binding pocket. The responsive systems were made by linking a crown ether to a kinetically inert lanthanide binding pocket using a molecular building block approach. Specifically, an alkyne-appended Ln.DO3A was used as a building block in a copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) "click" reaction with azide-functionalized crown ethers. The resulting complexes were investigated using NMR and optical methods. Titrations with potassium chloride in methanol observing the sensititzed europium- and terbium-centered emissions were used to investigate the response of the systems. The molecular reporters based on aliphatic crown ethers were found to have strongly inhibited binding of potassium, while the benzo-18-crown-6 derived systems had essentially the same association constants as the native crown ethers. The shape of the lanthanide emission spectra was shown to be unperturbed by the binding of potassium, while the binding was reported by an overall increased intensity of the lanthanide-centered emission. This observation was contrasted to the change in spectral shape between propargyl-Ln.DO3A and the triazolyl-Ln.DO3A complexes. The solution structure of the lanthanide complexes was found to be determining for the observed physical chemical properties of these systems.

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“…There has been much recent effort in studying the photophysical properties of d/f dyads in which this antenna group is a transition-metal complex fragment rather than an organic ligand. 1 − 3 This requires the d-block component to have a high absorption coefficient, and an excited state which is long-lived enough such that energy-transfer to the lanthanide(III) ion is a significant deactivation pathway that competes favorably with other radiative and nonradiative deactivation processes. It also requires that the energy of the excited state of the d-block component lies sufficiently far above that of the emissive level of the lanthanide(III) ion that d→f energy-transfer has a large enough thermodynamic gradient to prevent back energy-transfer.…”

Section: Introductionmentioning

confidence: 99%

d→f Energy Transfer in Ir(III)/Eu(III) Dyads: Use of a Naphthyl Spacer as a Spatial and Energetic “Stepping Stone”

et al. 2013

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A series of luminescent complexes based on {Ir(phpy)2} (phpy = cyclometallating anion of 2-phenylpyridine) or {Ir(F2phpy)2} [F2phpy = cyclometallating anion of 2-(2′,4′-difluorophenyl)pyridine] units, with an additional 3-(2-pyridyl)-pyrazole (pypz) ligand, have been prepared; fluorination of the phenylpyridine ligands results in a blue-shift of the usual 3MLCT/3LC luminescence of the Ir unit from 477 to 455 nm. These complexes have pendant from the coordinated pyrazolyl ring an additional chelating 3-(2-pyridyl)-pyrazole unit, separated via a flexible chain containing a naphthalene-1,4-diyl or naphthalene-1,5-diyl spacer. Crystal structures show that the flexibility of the pendant chain allows the naphthyl group to lie close to the Ir core and participate in a π-stacking interaction with a coordinated phpy or F2phpy ligand. Luminescence spectra show that, whereas the {Ir(phpy)2(pypz)} complexes show typical Ir-based emission—albeit with lengthened lifetimes because of interaction with the stacked naphthyl group—the {Ir(F2phpy)2(pypz)} complexes are nearly quenched. This is because the higher energy of the Ir-based 3MLCT/3LC excited state can now be quenched by the adjacent naphthyl group to form a long-lived naphthyl-centered triplet (3nap) state which is detectable by transient absorption. Coordination of an {Eu(hfac)3} unit (hfac = 1,1,1,5,5,5-hexafluoro-pentane-2,4-dionate) to the pendant pypz binding site affords Ir–naphthyl–Eu triads. For the triads containing a {Ir(phpy)2} core, the unavailability of the 3nap state (not populated by the Ir-based excited state which is too low in energy) means that direct Ir→Eu energy-transfer occurs in the same way as in other flexible Ir/Eu complexes. However for the triads based on the{Ir(F2phpy)2} core, the initial Ir→3nap energy-transfer step is followed by a second, slower, 3nap→Eu energy-transfer step: transient absorption measurements clearly show the 3nap state being sensitized by the Ir center (synchronous Ir-based decay and 3nap rise-time) and then transferring its energy to the Eu center (synchronous 3nap decay and Eu-based emission rise time). Thus the 3nap state, which is energetically intermediate in the {Ir(F2phpy)2}–naphthyl–Eu systems, can act as a “stepping stone” for two-step d→f energy-transfer.

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Synthesis and Spectroscopic Study of d–f Hybrid Lanthanide Complexes Derived from triazolylDO3A

Cited by 47 publications

References 24 publications

Photophysics and photochemistry of 1,2,3-triazole-based complexes

Photophysics and photochemistry of 1,2,3-triazole-based complexes

Kinetically Inert Lanthanide Complexes as Reporter Groups for Binding of Potassium by 18-crown-6

d→f Energy Transfer in Ir(III)/Eu(III) Dyads: Use of a Naphthyl Spacer as a Spatial and Energetic “Stepping Stone”

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