By using UV-Visible and fluorescence measurements, a new chemosensor N-(pyrimidin-2-yl) thiophene-2-carboxamide (PTC) was introduced for the discriminating and responsive detection of Fe3+ in aqueous methanolic medium. Since the PTC-Fe3+ complexation occurred in 1:1 binding stoichiometry, the receptor PTC preferentially revealed a charge transfer band between 310 to 475 nm in the UV-Vis technique, with the absorption peak at 351 nm. Furthermore, the fluorescence technique, which dampened PTC's fluorescence emission band at 325 nm, showed similar selectivity. The Stern-Volmer graphic shows that fluorescence quenching occurs in a static manner. The series of examined metal ions (Na+, K+, Li+, Cs+, Fe2+, Ni2+, Sr2+, Cu2+, Cd2+, Pb2+, Co2+, Hg2+, Ba2+, Mg2+, Mn2+, Ca2+, Zn2+, Cr3+, Ag+ and Al3+) failed to perturb the UV-Vis and fluorescence of PTC. With PTC, the concentration of Fe3+ can be detected down to 2.03 and 1.24 µM by UV-Vis and fluorescence methods, respectively.
HIGHLIGHTS
An easy-to-synthesize pyrimidine-based receptor PTC was developed for the detection of Fe3+
PTC showed Fe3+selective turn-off fluorescence and a new charge transfer absorption band at 351 nm
LOD of PTC is 2.03 and 1.24 µM, respectively by UV-Vis and fluorescence methods
Fluorescence quenching is static in nature
GRAPHICAL ABSTRACT