![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
2-Arylazo-5,5,10,10,15,15,20,20-octamethylcalix[4]pyrroles (azo-OMCPs) have been synthesised by the reaction of calix[4]pyrrole with aryldiazonium chloride in 15–45% yields. The solution-state binding studies of the synthesised hosts were investigated by absorption spectroscopy and 1H NMR in DMSO and CDCl3, respectively. These receptors, appended with electron-donating and electron-withdrawing groups, displayed enhanced affinity and selectivity for fluoride anion. Well-defined colour change in the visible region of the spectrum was observed upon addition of fluoride ion in DMSO solution of azo-OMCPs. Detailed NMR studies in CDCl3 revealed that azo-OMCPs with nitro and chloro groups have higher binding affinity for fluoride ion.
Acknowledgements
The authors are thankful to the Department of Science and Technology (DST) for project no. SR/S1/OC-54/2003, Council of Scientific and Industrial Research (CSIR) and University of Delhi, New Delhi, for their financial assistance.