Jump to main content
Jump to site search


The effect of the linker size in C2-symmetrical chiral ligands on the self-assembly formation of luminescent triple-stranded di-metallic Eu(III) helicates in solution

Abstract

Chiral lanthanide-based supramolecular structures have gained significant importance in view of their application in imaging, sensing and other functional purposes. We have designed chiral C2-symmetrical ligands (L) based on the use of two 2,6-pyridine-dicarboxylic-amide moieties (pda), that differ from one another by the nature of the diamine spacer groups (from 1,3-phenylenedimethanamine (1(S,S), 2(R,R)) and benzene-1,3-diamine (3(S,S), 4(R,R)) to much bulkier 4,4'-(cyclohexane-1,1-diyl)bis(2,6-dimethylaniline) (5(S,S), 6(R,R))) between these two pda units. The self-assembly between L and Eu(III) ions were investigated in CH3CN solution at low concentration whereby the changes in the absorbance, fluorescence and Eu(III)-centred emission spectra allowed us to model the binding equilibria occurring in the solution to the presence of [Eu:L2], [Eu2:L2], [Eu2:L3] assemblies and reveal their high binding constant values. The self-assembly in solution were also studied at higher concentration by following the changes in the 1H NMR spectra of the ligands upon Eu(III) addition, as well as by using MALDI-MS of the isolated solid state complexes. The chiroptical properties of the ligands were used in order to study the structural changes upon self-assembly between the ligands and Eu(III) ions using circular dichroism (CD) and circularly polarised luminescence (CPL) spectroscopies. The photophysical properties of [Eu2:L3] complexes were evaluated in solution and showed the decrease of luminescence quantum yield when going from smaller to bulkier linkers from ∼5.8% to ∼3.2-2.6 %. While mass-spectrometry revealed the possible formation of trinucler assemblies such as [Eu3:L3] and [Eu3:L2].

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Jul 2018, accepted on 09 Aug 2018 and first published on 09 Aug 2018


Article type: Paper
DOI: 10.1039/C8DT02753F
Citation: Dalton Trans., 2018, Accepted Manuscript
  •   Request permissions

    The effect of the linker size in C2-symmetrical chiral ligands on the self-assembly formation of luminescent triple-stranded di-metallic Eu(III) helicates in solution

    T. Gunnlaugsson, O. Kotova, S. Comby, K. Pandurangan, F. Stomeo, J. E. O'Brien, M. Feeney, R. Peacock and C. McCoy, Dalton Trans., 2018, Accepted Manuscript , DOI: 10.1039/C8DT02753F

Search articles by author

Spotlight

Advertisements