Simple fabrication of a carbaldehyde based fluorescent “turn-on” probe for the selective and sole detection of Pd2+: application as test strips

Abstract

A new fluorescent “turn-on” probe (DHMC) has been designed and synthesized to selectively detect Pd²⁺ among other cations at physiological pH. Upon incremental addition of Pd²⁺ into the probe solution, a “turn-on” emission enhancement was noticed with a ∼69 nm red shift at 562 nm in CH₃CN/H₂O (4/1, v/v) solution. The limit of detection and binding constant values have been determined and found to be on the order of 7.4 × 10⁻⁸ M and 1.7 × 10⁵ M⁻¹ respectively, which clearly suggests that the probe is very efficient in detecting Pd²⁺ at very minute levels and also the DHMC–Pd²⁺ complexation is stable enough too. A brilliant application of the probe has been explored which indicates that DHMC can detect Pd²⁺ in the solid state too. DFT and TDDFT calculations are carried out to interpret the electronic structure and sensing mechanism.