Conjugated Polyelectrolyte With Phosphorescent Iridium(â…¢) Complex: Design, Synthesis And Their Applications

Water-soluble conjugated polyelectrolytes(CPEs) mainly composed of a rigid hydrophobic π-conjugated main chain and water-soluble ionic side chains. Its unique conjugated main chain skeleton, upon receipt of the external signal, the electrons or energy can fast migrate on the chain, showed signal amplification effect, resulting in greatly improve the detection sensitivity in biochemical sensing applications. Phosphorescent transition metal complexes(PTMC) exhibit several unique photophysical properties compared with pure organic luminophores, such as high quantum efficiency, long emission lifetime, tunable emission wavelength, large Stokes shift, and can be excited in visible range, make it gain increased attention in sensing and imaging applications during the recent years. In this article, combining the advantages of conjugated polyelectrolyte and phosphorescent transition metal complexes to yield a new series of phospor-containing transition metal complexes soluble conjugated polyelectrolyte materials. We study their photophysical properties and explore its application in chemical and biological sensors(ion detection) and cell imaging. Topics include the following two aspects.1. A dual-emissive conjugated polyelectrolyte containing phosphorescent iridium(III) complex was designed and synthesized, which can form ultrasmall polymer dots(Pdots) in aqueous media. The F--responsive tert-butyldiphenylsilyl moiety was introduced into iridium(III) complex as the signaling unit for sensing F- with the quenched phosphorescence. Thus, the dual-emissive Pdots can rapidly and accurately detect F- in aqueous media and live cells as a ratiometric probe by measuring the change in the ratio of the F--sensitive red phosphorescence from iridium(III) complex to the F--insensitive blue fluorescence from polyfluorene. Moreover, the interaction of Pdots with F- also changes its emission lifetime, and the lifetime-based detection of F- in live cells has been realized through photoluminescence lifetime imaging microscopy.2. A hypochlorite probe containing transition metal iridium complexes was designed and synthesized. The probe has a good spectral responsivity in methanol/water system. The probe has achieved good results for its applied to the detection of intracellular hypochlorite, lifetime imaging and time-gate imaging. At the same time, we hope to introduce the transition metal iridium complexes into the CPs to yield a new series hypochlorite probe for chemo/biosensing and bioimaging applications.