Abstract
A zinc-selective probe based on a set of rare earth complexes of a modified DO3A macrocyclic ligand incorporating a tris-pyridylamine (TPA) moiety has been structurally characterised in solution and in the solid-state. One pyridine group possesses a tert-butyl substituent to serve as an NMR reporter group. The mono-capped square-antiprismatic Dy complex has a long bond (2.83 Å) to an apical N atom (pK a 5.70 Eu) and binds to one water molecule on zinc binding. Zinc binding is reversible and involves all of the exocyclic ligand N donors; it is signalled by large (ratiometric) changes in Eu emission intensity, and by dramatic changes in the size (>50 ppm) and sign of the chemical shift of the paramagnetically shifted tBu resonances in Tb, Dy and Tm complexes. Slow trans-metallation was observed, leading to formation of an unusual di-zinc species in which one zinc ion is seven-coordinate and the other is six-coordinate.
| Original language | English |
|---|---|
| Pages (from-to) | 6212-6225 |
| Number of pages | 14 |
| Journal | Chemistry - A European Journal |
| Volume | 25 |
| Issue number | 24 |
| Early online date | 12 Mar 2019 |
| DOIs | |
| Publication status | Published - 26 Apr 2019 |
User-Defined Keywords
- emission
- lanthanides
- NMR
- paramagnetic
- zinc