Using Remote Substituents to Control Solution Structure and Anion Binding in Lanthanide Complexes

Tropiano, Manuel; Blackburn, Octavia A.; Tilney, James A.; Hill, Leila R.; Placidi, Matteo P.; Aarons, R. J.; Sykes, Daniel; Jones, Michael W.; Kenwright, Alan M.; Snaith, J. S.; Sørensen, Thomas Just; Faulkner, Stephen

doi:10.1002/chem.201303183

Cited by 31 publications

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“…[14][15][16] One outcome of this research is that we now have the tools to probe and control the structure and speciation of lanthanide(III) ions in aqueous media, [17][18][19][20] in particular when working with kinetically inert complexes. 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.…”

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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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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“…Eu 2 ⋅ 2 , Scheme ), Eu 2 ⋅ 1 displayed strong selectivity for isophthalate at 16,660 m −1 in the presence of 1 m m lithium hydroxide, compared with 24,600 m −1 in pure methanolic solution. Not only does this provide evidence of competitive binding by hydroxide, but the value in the absence of hydroxide is five times lower than that determined for Eu 2 ⋅ 2 . To investigate this further, we studied the binding of phthalate and terephthalate, determining the binding constants in methanol in the presence of 1 m m lithium hydroxide.…”

Section: Resultsmentioning

confidence: 91%

“…5‐Nitro‐α,α′‐bis(Eu⋅DO3Ayl)‐ m ‐xylene (Eu 2 ⋅ 1 ) was prepared as previously described . The salt content was determined using elemental analysis, while the europium content was determined using inductively coupled plasma mass spectrometry (ICP‐MS).…”

Section: Methodsmentioning

confidence: 99%

“…The isophthalate motif can also be used to direct the assembly of more complicated multimetallic f,f ’ and d , f complexes . We recently observed that changing the remote substituent on the m ‐xylyl linking group can be used to control the binding affinity of the complex for an isophthalate guest, and that binding can be precluded or enhanced depending on the nature of the remote substituent . Affinity constants ( K ) between 0 and 10 7 m −1 were observed, and the considerable changes in this system were ascribed to preorganisation of the binuclear complex and removal of “inactive” conformers from the conformational space available within the structure .…”

Section: Introductionmentioning

confidence: 99%

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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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“…2 and Table S1, ESI †). 34,37,38 These conformational changes will, of course, have direct consequences on the relaxation through self-assembly. Somewhat counter-intuitively, relaxometric characteristics were less strongly enhanced at high solution pH (9)(10)(11)(12) also.…”

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Ligation driven ¹⁹F relaxation enhancement in self-assembled Ln(iii) complexes

et al. 2015

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Using Remote Substituents to Control Solution Structure and Anion Binding in Lanthanide Complexes

Cited by 31 publications

References 43 publications

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

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

Ligation driven ¹⁹F relaxation enhancement in self-assembled Ln(iii) complexes

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Using Remote Substituents to Control Solution Structure and Anion Binding in Lanthanide Complexes

Cited by 31 publications

References 43 publications

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

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

Ligation driven 19F relaxation enhancement in self-assembled Ln(iii) complexes

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Ligation driven ¹⁹F relaxation enhancement in self-assembled Ln(iii) complexes