Synthesis of bispyrenyl sugar-aza-crown ethers as new fluorescent molecular sensors for Cu(II).
Two N-pyrenylacetamide-substituted sugar-aza-crown ethers have been synthesized as new fluorescent chemosensors. The designed ligands 1 and 2 exhibit fluorescence characteristics of a pyrene monomer and a dynamic excimer emission when compared to N-pyrenylacetamide as a model compound. Both ligands displayed a Cu2+-sensitive fluorescence quenching with a 1:1 stoichiometry and high stability constants (log K = 6.7 for 1 and 7.8 for 2). The quenching effect was rationalized on the basis of photoinduced electron transfer from the excited pyrene to the complexed Cu2+ cation, while the changes in excimer-to-monomer ratio were explained by a conformational analysis through DFT calculations. The predicted structure suggests that the Cu2+ cation is coordinated with the two carbonyl groups and the sugar-aza-crown ethers which rigidified the complex structure and placed the two pyrene moieties far apart.
Xie
Juan
J
PPSM, Institut d'Alembert, ENS Cachan, CNRS, UniverSud, 61 Avenue du President Wilson, F-94230 Cachan, France. joanne.xie@ppsm.ens-cachan.fr
Ménand
Mickaël
M
Maisonneuve
Stéphane
S
Métivier
Rémi
R
D002241:Carbohydrates / Q000737:chemistry*; D002412:Cations; D002625:Chemistry, Organic / Q000379:methods*; D003300:Copper / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D013050:Spectrometry, Fluorescence
D002241:Carbohydrates; D002412:Cations; D043844:Crown Ethers; D008024:Ligands; D003300:Copper