Lower rim isoxazole-calix[4]arene derivatives as fluorescence sensors for copper(II) ions

TETRAHEDRON

卷:71

Article

Maher, Niall J.¹  Diao, Haowen¹  O'Sullivan, Justine¹  Fadda, Elisa¹  Heaney, Frances¹  McGinley, John¹ 

[1] Maynooth Univ, Dept Chem, Maynooth, Kildare, Ireland

关键词: Calix[4]arene;    Isoxazole;    NOAC chemistry;    Fluorescence;    X-ray structure;    DFT;   

DOI  :  10.1016/j.tet.2015.10.045

来源: Elsevier

【 摘 要 】

Chemosensors designed around a calix[4]arene scaffold, possessing distal isoxazole nuclei as potential recognition sites in conjugation with fluorogenic reporting moieties, have been synthesised and their molecular structures determined by single crystal X-ray analysis. PIC (pyrene-isoxazole-calix[4]arene) and AIC (anthracene-isoxazole-calix[4]arene) are found to be selective and sensitive for the recognition of copper(II) ions over a range of divalent metal ions in a spectrofluorometric study in acetonitrile. Following exposure to copper(II) ions the fluorescence emission intensity of the host was dramatically quenched, in contrast there were no significant shifts to the UV-vis spectra. H-1 NMR spectroscopic studies could not provide unambiguous evidence for the mode of ion recognition. Hybrid Density Functional Theory (DFT) calculations for the PIC-copper(II) complex suggests that the metal ion adopts tetrahedral geometry in an acetonitrile solution, while a distorted square pyramidal coordination is also possible in the absence of solvent molecules. Both of these binding conformations cause the disruption of the pyrene-pyrene stacking, consistent with the observed fluorescence quenching. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free