Self‐Assembly between Dicarboxylate Ions and Dinuclear Lanthanide Complexes: A Surprisingly Complicated Problem

Sørensen, Thomas Just; Hill, Leila R.; Tilney, James A.; Blackburn, Octavia A.; Jones, Michael W.; Tropiano, Manuel; Faulkner, Stephen

doi:10.1002/ejic.201402169

Cited by 13 publications

(13 citation statements)

References 44 publications

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“…Here we stipulate that secondary effects-such as unspecific binding and ionic strength-drastically alter the photophysical properties of the Ln.L 3 complexes upon addition of an excess of potassium chloride. [71][72] Note that the increase in intensity of emission from Ln.L 3 greatly exceeds the changes in intensity in Ln.L 2 upon binding of potassium.…”

Section: Response To Potassiummentioning

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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Section: Response To Potassiummentioning

confidence: 99%

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

et al. 2016

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“…This new level of control informs the design of responsive luminescent probes, [21][22][23][24][25][26] and allows for detailed physico-chemical investigations in solution. 19,[27][28][29][30][31][32] Extensive published work has determined that ligands comprising a cyclen scaffold and three or four carboxylate (e.g. DO3A, DOTA…) or carboxamide (e.g.…”

Section: Introductionmentioning

confidence: 99%

Investigating subtle 4f vs. 5f coordination differences using kinetically inert Eu(iii), Tb(iii), and Cm(iii) complexes of a coumarin-appended 1,4,7,10-tetraazacyclododecane-1,4,7-triacetate (DO3A) ligand

et al. 2018

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TitleInvestigating subtle 4f vs. 5f coordination differences using kinetically inert Eu(iii), Tb(iii), and Cm(iii) complexes of a coumarin-appended 1,4,7,10-tetraazacyclododecane-1,4,7-triacetate (DO3A) ligand In order to reveal subtle differences between the solution chemistries of trivalent 4f and 5f elements, the physicochemical and photophysical properties of europium(III), terbium(III) and curium(III) complexes formed with a 7-methoxy-coumarin appended 1,4,7,10-tetraazadodecane-1,4,7-triacid (DO3A) ligand were studied. All three complexes were found to be kinetically inert and exhibit stability constants similar to their 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) equivalents. The Cm(III) and Eu(III) complexes feature strong sensitised emission, while the triplet energy of the coumarin prohibits efficient sensitisation of the Tb(III) analogue. The data presented here indicate significant differences in perturbation of the sensitising chromophore photophysics between the 4f and 5f elements. In contrast, the size of the metal center appears to not be a determining factor for the physicochemical properties of these kinetically inert Eu(III), Tb(III,) and Cm(III) complexes.

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“…Titrations of Eu 2 ·1 were carriedo ut with the anions shown in Scheme 1u sing ap reviously described procedure. [33] Briefly, a1 0 À5 m solution of the lanthanide complex in the solvent system under study was used to prepare a1 0 À3 m solution of the carboxylate species, containing 10 À5 m of the lanthanide complex. In doing so, the concentration of the lanthanide complex remained constantd uring the titration.…”

Section: Studying Self-assemblymentioning

confidence: 99%

“…conformer in such circumstances effectively precludesb inding. [32] These observations,t ogether with the fact that solventp lays ad ominant role in determining the value of the affinity constant, [33] made us consider the thermodynamics of binding in detail. Here, we describet he results of as tudy in which we look at the role of solventa nd buffer, and establish enthalpic and entropic contributions to the thermodynamicso fa nion binding.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of Self‐Assembly of Dicarboxylate Ions with Binuclear Lanthanide Complexes

2015

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Self-assembly of a range of carboxylic acids (benzoic acid, dinicotinic acid, nicotinic acid, and isophthalic acid) with the europium complex of 5-nitro-α,α′-bis(DO3Ayl)-m-xylene (where DO3A is 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) has been explored to establish the thermodynamics of binding in a range of solvent systems and in a range of aqueous buffer solutions. In this system, profound effects are observed as a consequence of competition by the hydroxide ion, which outcompetes even dinicotinate at high pH. In the case of isophthalate, which binds most strongly, and dinicotinate, both enthalpic and entropic contributions to binding have been identified. The europium complex with 5-nitro-α,α′-bis(DO3Ayl)-m-xylene is found to have a solution structure significantly different from the related europium complex of 5-amino-α,α′-bis(DO3Ayl)-m-xylene. It is found that phosphate binds strongly to the europium complex of the nitro derivate but not to the europium complex of amino derivative. Lactate, citrate, and pyruvate also bind strongly to 5-nitro-α,α′-bis(Eu⋅DO3Ayl)-m-xylene, and it is concluded that the solution structure of this binuclear lanthanide complex is significantly different from that of the amino-substituted complex.

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Self‐Assembly between Dicarboxylate Ions and Dinuclear Lanthanide Complexes: A Surprisingly Complicated Problem

Cited by 13 publications

References 44 publications

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

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

Investigating subtle 4f vs. 5f coordination differences using kinetically inert Eu(iii), Tb(iii), and Cm(iii) complexes of a coumarin-appended 1,4,7,10-tetraazacyclododecane-1,4,7-triacetate (DO3A) ligand

Thermodynamics of Self‐Assembly of Dicarboxylate Ions with Binuclear Lanthanide Complexes

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