ABSTRACT
The well-known lanthanide-binding motif, 2,6-pyridinedicarboxamide, has been functionalised with peripheral substituents using copper-catalysed azide alkyne coupling (CuAAC) to develop new symmetrical ‘clicked’ N2,N6-bis((1-(X)-1H-1,2,3,-triazol-4-yl)methyl)pyridine- 2,6-dicarboxamide (where X = ethyl (1) benzyl (2) and 2-naphthyl (3)). These ligands have been successfully coordinated with trivalent lanthanide ions (europium, terbium, and lanthanum) forming [Ln(L)3](CF3SO3)3 complexes. The ligands act as effective antennae for Eu3+ and Tb3+ complexes, which exhibit the characteristic sensitised emission profiles. The ability of 1–3 to assemble into 1:3 M:L systems in solution was investigated using UV-Vis, fluorescence, and NMR. Finally, density functional calculations of the ground state La3+ complexes have been carried out and show similar geometry and coordination parameters to those with available crystallographic data. The facile and modular synthesis of these ‘clicked’ PDC-based ligands makes these compounds excellent candidates for luminescent supramolecular materials development.
Acknowledgments
We would like to thank Ian Stewart for collecting Mass Spec., the New Zealand Ministry of Business, Innovation and Employment and the Royal Society Te Apārangi, for a Catalyst: Seeding fund.
Disclosure statement
No potential conflict of interest was reported by the author(s).