Urea based dipodal fluorescence receptor for sensing of Fe3+ ion in semi-aqueous medium

Urea based fluorescent chemosensor 1 was synthesized. Receptor 1 shows unique selectivity for the Fe3+ion and no such significant response was noticed with other metal ions (Cr3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ and Bi3+) in DMSO/H2O (50:50,v/v) semi-aqueous solution. The binding features have been established by absorption and fluorescence spectroscopic methods. The binding constant (K) values obtained from Benesi-Hildebrand, Scatchard and Connor plot for receptor 1 is (8.3 ± 0.3) × 103 M−1 and has good detection limit 0.7 μM. The stoichiometry of 1.Fe3+ complex was confirmed by mass spectroscopy and Job’s plot.