A selective colorimetric chemosensor for Fe3+

Two simple colorimetric receptors PS and PP (thiophene and pyridine appended derivative) were prepared and their cation sensing properties were investigated. Receptors PS and PP displayed a selective colorimetric change (from colorless to orange) upon binding to Fe3+ in MeOH solution. The association constants for receptors PS–Fe3+ and PP–Fe3+ in MeOH were determined to be 1.15 × 106 and 4.31 × 106 M−1, respectively, using Hill plots. The detection limits of PS and PP were 490.7 ppm and 393.7 ppm, respectively.