Xie Juan, Ménand Mickaël, Maisonneuve Stéphane, Métivier Rémi
PPSM, Institut d'Alembert, ENS Cachan, CNRS, UniverSud, 61 Avenue du President Wilson, F-94230 Cachan, France.
J Org Chem. 2007 Aug 3;72(16):5980-5. doi: 10.1021/jo070315y. Epub 2007 Jul 12.
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.
两种N-芘基乙酰胺取代的糖氮杂冠醚已被合成为新型荧光化学传感器。与作为模型化合物的N-芘基乙酰胺相比，设计的配体1和2表现出芘单体的荧光特性和动态激基缔合物发射。两种配体均表现出对Cu2+敏感的荧光猝灭，化学计量比为1:1，且具有高稳定性常数（1的log K = 6.7，2的log K = 7.8）。猝灭效应基于从激发态芘到络合的Cu2+阳离子的光诱导电子转移得到合理解释，而激基缔合物与单体比例的变化则通过DFT计算的构象分析来解释。预测结构表明，Cu2+阳离子与两个羰基以及糖氮杂冠醚配位，这使络合物结构刚性化，并使两个芘部分相距较远。
