Using remote substituents to control solution structure and anion binding in lanthanide complexes

TY - JOUR

T1 - Using remote substituents to control solution structure and anion binding in lanthanide complexes

AU - Tropiano, Manuel

AU - Blackburn, Octavia A.

AU - Tilney, James A.

AU - Hill, Leila R.

AU - Placidi, Matteo P.

AU - Aarons, Rebecca J.

AU - Sykes, Daniel

AU - Jones, Michael W.

AU - Kenwright, Alan M.

AU - Snaith, John S.

AU - Sørensen, Thomas Just

AU - Faulkner, Stephen

N1 - Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PY - 2013/12/2

Y1 - 2013/12/2

N2 - A study of the anion-binding properties of three structurally related lanthanide complexes, which all contain chemically identical anion-binding motifs, has revealed dramatic differences in their anion affinity. These arise as a consequence of changes in the substitution pattern on the periphery of the molecule, at a substantial distance from the binding pocket. Herein, we explore these remote substituent effects and explain the observed behaviour through discussion of the way in which remote substituents can influence and control the global structure of a molecule through their demands upon conformational space. Peripheral modifications to a binuclear lanthanide motif derived from α,α'-bis(DO3 Ayl)-m-xylene are shown to result in dramatic changes to the binding constant for isophthalate. In this system, the parent compound displays considerable conformational flexibility, yet can be assumed to bind to isophthalate through a well-defined conformer. Addition of steric bulk remote from the binding site restricts conformational mobility, giving rise to an increase in binding constant on entropic grounds as long as the ideal binding conformation is not excluded from the available range of conformers.

AB - A study of the anion-binding properties of three structurally related lanthanide complexes, which all contain chemically identical anion-binding motifs, has revealed dramatic differences in their anion affinity. These arise as a consequence of changes in the substitution pattern on the periphery of the molecule, at a substantial distance from the binding pocket. Herein, we explore these remote substituent effects and explain the observed behaviour through discussion of the way in which remote substituents can influence and control the global structure of a molecule through their demands upon conformational space. Peripheral modifications to a binuclear lanthanide motif derived from α,α'-bis(DO3 Ayl)-m-xylene are shown to result in dramatic changes to the binding constant for isophthalate. In this system, the parent compound displays considerable conformational flexibility, yet can be assumed to bind to isophthalate through a well-defined conformer. Addition of steric bulk remote from the binding site restricts conformational mobility, giving rise to an increase in binding constant on entropic grounds as long as the ideal binding conformation is not excluded from the available range of conformers.

U2 - 10.1002/chem.201303183

DO - 10.1002/chem.201303183

M3 - Journal article

C2 - 24203895

SN - 0947-6539

VL - 19

SP - 16566

EP - 16571

JO - Chemistry: A European Journal

JF - Chemistry: A European Journal

IS - 49

ER -