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.