Nanomolar Detection of Palladium (II) through a Novel Seleno-Rhodamine-based fluorescent and colorimetric chemosensor

A novel reversible fluorescent probe for Pd2+ based on a rhodamine-containing selenide (Rh–Se) was designed, synthesized and fully characterized. The probe Rh–Se showed a high selectivity and sensitivity with a detection limit of 32 nM for Pd2+ ions. The formation of a complex Rh–Se/Pd2+ was confirmed by HRMS. DFT calculations revealed that the proposed square planar geometry is the most stable form of the metallic complex Rh–Se/Pd2+. The probe Rh–Se showed to have high potential for the detection of residual Pd2+ in synthetic cross-coupling products and simulated pharmaceutical Pd2+- contaminated products.