Abstract
A strapped calix[4]pyrrole (2) with a fluorogenic pyrene unit linked to the rigid strap via the methylene bridge has been synthesised. It was established by 1H NMR and fluorescence spectroscopic analyses and isothermal titration calorimetry (ITC) studies that receptor 2 is capable of binding the F−, Cl−, (ppi) and anions in organic media, with high selectivity for F− being observed relative to the other anions. Upon exposure to the F− and , the fluorescence of 2 is quenched, an effect ascribed to facilitated PET (photo-induced electron transfer) from the nitrogen atom to the pyrene moiety, which is induced by anion binding. In contrast, the fluorescence of 2 was enhanced upon treatment with the HSO4− anion as the result of the PET inhibition that results from nitrogen atom protonation. A single crystal X-ray structure of the chloride complex of 2 and the 1H NMR spectral data revealed that the chloride anion is bound to the receptor via aliphatic C–H•••Cl− hydrogen bonds, as well as N–H•••Cl− interactions.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.