Near-IR oxime-based solvatochromic perylene diimide probe as chemosensor for Pd species and Cu2+ ions in water and live cells
Near-IR perylene diimide probe (OPR-PDI) containing oxime-propargyl hybrid moiety at bay position, was designed and synthesized for detection of Pd species and Cu2+ ions in 90% water, solid state and MG-63 live cells. The aggregation tendency of OPR-PDI in different polarity solvents transmit solvatochromic and fluorochromic properties to differentiate certain organic solvents. Supramolecular aggregates of OPR-PDI in 90% water act as a dual chemosensor for palladium (Pd) species via de-propargylation or hydrolysis of Schiff-base and Cu2+ ion via complexation with O/N binding site with low limit of detection (LOD) of the order of 7.9x10-8 M and 3.4x10-7 M respectively. TLC strips coated with OPR-PDI can be applied for sensing of Pd0 and Cu2+ ions in solid state as low as 34.6 ng/cm2 and 10.5 ng/cm2. OPR-PDI imprinted TLC strips could be used as paper sheet for writing colored alphabets using Pd0 and Cu2+ ions as ink. Moreover, MTT assay show that OPR-PDI has very low cytotoxicity (IC50 = 230 µM), good permeability, biocompatibility and applied for bio-imaging of Pd species and Cu2+ ions in MG-63 cells. The DFT calculations, cyclic voltammetric (CV) and NMR titration studies have also been discussed.