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 Fe(3+)ion and no such significant response was noticed with other metal ions (Cr(3+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), Pb(2+) and Bi(3+)) 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) × 10(3) M(-1) and has good detection limit 0.7 μM. The stoichiometry of 1.Fe(3+) complex was confirmed by mass spectroscopy and Job's plot.