Simple Conjugated Polymers with On‐Chain Phosphorescent Iridium(III) Complexes: Toward Ratiometric Chemodosimeters for Detecting Trace Amounts of Mercury(II)

Abstract

For the development of excellent optical probes for mercury(II), a series of simple conjugated polymers that contain phosphorescent iridium(III) complexes as receptors for mercury(II) were designed and synthesized. These conjugated polymers showed energy transfer from the polymer host to iridium(III) complex guest in both solution and the solid state. Unexpectedly, they can work as excellent polymer chemodosimeters for mercury(II) by utilizing the mercury(II)-induced decomposition of iridium(III) complex. They exhibit a pronounced optical signal change with switchable phosphorescence and fluorescence, even when the concentration of a solution of mercury(II) in THF was as low as 0.5 ppb. With the addition of mercury(II), the phosphorescent emission intensity of iridium(III) complexes was quenched completely. As the emission from polymer backbones increased, the emission wavelength was redshifted simultaneously, thereby realizing ratiometric detection. Excellent selectivity toward mercury(II) over other potentially interfering cations was also realized. In addition, an obvious emission color change of polymer solution from red to yellow-green was observed, thus realizing a "naked-eye" detection of mercury(II). More importantly, the solid films of these polymer chemodosimeters also exhibited high sensitivity and rapid response to mercury(II), thereby demonstrating the possibility of the fabrication of sensing devices with fast and convenient detection of mercury(II). The sensing mechanism was also investigated in detail. This is the first report on chemodosimeters based on conjugated polymers with phosphorescent iridium(III) complexes.

Exceptional Blueshifted and Enhanced Aggregation‐Induced Emission of Conjugated Asymmetric Triazines and Their Applications in Superamplified Detection of Explosives

“…Recently, organic fluorescent probes based on p-conjugated molecules have attracted great attention because of their advantages in terms of sensitivity, selectivity, response time, and low cost. [6] The emission of conventional luminophores, however, is often weakened or even totally annihilated when molecules aggregate due to energy transfer and the formation of excimers or exciplexes. Therefore, AIE-active molecules are now under the spotlight.…”

“…The donor-acceptor (D-A) molecular design strategy [1] is one of the most efficient methods to prepare desired materials for various optoelectronic devices, [2] such as organic light-emitting diodes (OLEDs), [3] organic photovoltaics (OPV), [4] organic field-effect transistors (OFETs), [5] sensors, [6] and organic lasers. [7] However, despite the facile manipulation of the frontier orbital energy levels, energy band gaps, and carrier injection and transport balance of D-A molecules, [8] the photoluminescence (PL) spectra can shift easily to longer wavelengths due to intramolecular chargetransfer (ICT) interactions in the D-A molecular architecture.…”

Vibrational spectroscopy study on α and β phases in iridium‐complex‐containing polyfluorenes

“…The PFO copolymers were synthesized through Suzuki polycondensation reaction from fluorene monomers and Ir(thq) 2 (dbm) monomer according to our previous report [4]. The concentrations of the Ir(III)-complex are 2, 4, 8, 12, 16, and 20 mol%.…”

A Colorimetric and Luminescent Dual-Modal Assay for Cu(II) Ion Detection Using an Iridium(III) Complex

“…The application of transition metal complexes as colorimetric and luminescent probes has recently attracted increasing attention [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30] due to their notable advantages. Firstly, the absorptive and emissive behaviour of transition metal complexes can be sensitive to changes in the surrounding environment, allowing changes in analyte concentration to be transduced into an optical response [31], [32].…”

“…Finally, the luminescence quantum yield of transition metal complexes can be enhanced by increased intersystem-crossing rates arising from strong spin-orbit interactions [49]. Among transition metal complexes, octahedral d 6 Ir(III) complexes have gained particular interest due to their decent thermal stability, intense luminescence at ambient temperature, and absorption or emission wavelengths across the entire visible light region that can be adjusted by modification of the auxiliary ligands [30], [50], [51].…”