Novel pyrene-pyridine oligomer nanorods for super-sensitive fluorescent detection of Pd2

A Review on Conducting Polymers for Colorimetric and Fluorescent Detection of Noble Metal Ions (Ag+, Pd2+, Pt2+/4+, and Au3+)

Conducting polymers (CPs) are conductive materials composed of organic polymers. CPs have excellent properties such as easy synthesis and effortless fabrication, tunable electrical property, high environmental stability, high mechanical and optical properties. These unique properties have attracted researchers to discover a wide variety of uses, such as batteries, solar cells, sensors, supercapacitors, electrochromic devices, and biochemical applications. Although CPs have many limitations in their pristine form, hybridization with other materials overcomes these limitations. Here in this review article, we discuss different CPs based chemosensors for colorimetric and fluorimetric detection and determination of noble metal ions (Ag+, Pd2+, Pt2+/4+, and Au3+) in different environmental, agricultural, and biological samples. Further, the sensing performances of these chemosensors have been compared and discussed. We hope this article will help the readers with the future design of CPs based optical sensor (colorimetric and fluorescent) for detecting noble metal cations.

A Boron Dipyrromethene-Based Fluorescence 'OFF-ON' Probe for Sensitive and Selective Detection of Palladium(II) Ions and Its Application in Live Cell Imaging

A novel boron dipyrromethene (BODIPY)-based fluorescent probe BDP-Pd was designed and synthesized. Upon coordination with Pd²⁺ , the emission of the probe at 508 nm significantly increased, showing an 'OFF-ON' fluorescence response. The complexation of BDP-Pd with Pd²⁺ in both acetonitrile and aqueous solution were then studied by absorption and fluorescence spectra. The binding stoichiometry between the probe and Pd²⁺ was found to be 1 : 2, and the binding constant was determined to be 8.5×10¹⁰  M^-2 and 8.2×10¹⁰  M^-2 in acetonitrile and aqueous solution, respectively. The probe exhibited a detection limit as low as 0.72 ppb toward Pd²⁺ with no obvious interference from up to 21 species of common metal ions, suggesting BDP-Pd as a sensitive and selective fluorescent probe for Pd²⁺ detection. The fast fluorescence 'OFF-ON' phenomenon of the probe upon coordination with Pd²⁺ ions could be easily observed by a hand-hold UV lamp under naked eye in solution as well as on homemade test trips. Density functional theory (DFT) calculations were carried out to give the optimized structure of complex BDP-Pd : 2Pd²⁺ and rationalize the detection mechanism through a prohibited intramolecular photoinduced electron transfer (PET) process. The bio-imaging application of the probe was investigated and it showed excellent cell permeability for fluorescent imaging of Pd²⁺ ions in A549 human non-small cell lung cancer cells.