Cyclen based bis-macrocyclic ligands as phosphates receptors. A potentiometric and NMR study.
The host-guest interaction between orthophosphate, pyrophosphate and triphosphate anions and four cyclen based bis-macrocycles ligands possessing ortho-(BOC), meta-(BMC), para-xylenyl (BPC) or 2,6-pyridinyl (BPyC) linker was investigated by potentiometric measurements and NMR spectroscopy. Each ligand gave protonated species in aqueous solution that further formed ternary complexes after binding with anions; these complexes were analyzed as a result of hydrogen bond formation and Coulombic attraction between the organic host and the inorganic guest. The equilibrium constants for all the detected species are reported and the selectivity, illustrated with species distribution diagrams, is discussed. The results unambiguously showed the importance of the distance between the two cyclen cores and underlined, especially for the triphosphate species, the contribution of the nitrogen atom of the pyridinyl spacer as a supplementary anchoring point in acidic medium.
Develay
Stéphanie
S
UMR CNRS 6521, Chimie, Electrochimie Moléculaire et Analytique, Université de Bretagne Occidentale, C. S. 93837, 6 avenue Victor Le Gorgeu, 29238 Brest Cedex 3, France.
Tripier
Raphaël
R
Le Baccon
Michel
M
Patinec
Véronique
V
Serratrice
Guy
G
Handel
Henri
H
D000838:Anions / Q000737:chemistry; D000080027:Cyclams; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D015394:Molecular Structure; D010710:Phosphates / Q000737:chemistry*; D011199:Potentiometry; D012680:Sensitivity and Specificity
D000838:Anions; D000080027:Cyclams; D006571:Heterocyclic Compounds; D008024:Ligands; D047028:Macrocyclic Compounds; D010710:Phosphates; C038072:cyclen