Coumarin- and rhodamine-fused deep red fluorescent dyes: synthesis, photophysical properties, and bioimaging in vitro.

A series of deep red fluorescent dyes (CR1 to CR3) was developed via introduction of a coumarin moiety into the rhodamine molecular skeleton. The novel dyes possessed the individual advantages of coumarin and rhodamine derivatives, and the emission wavelength was extended to the deep red region (>650 nm) due to the extension of fused-ring conjugate structure simultaneously. To illustrate its value, we designed and conveniently synthesized a series of novel deep red bioimaging dyes (CR1E to CR3E) by esterification of CR1 to CR3, which could selectively stain mitochondria. They were superior to the MitoTrackers for mitochondrial staining in terms of large Stokes shift, excellent contrast for imaging, high photostability, and low cytotoxicity. Furthermore, the fluorescence of the coumarin moiety and rhodamine-like fluorophore could be switched like classical rhodamine. Thus, they could be used as an effective platform in constructing fluorescence sensors. Based on this fact, we constructed a novel ratiometric sensor (CR1S) for Hg(2+) with good selectivity that could be successfully applied to the imaging of Hg(2+) in living A549 cells. This design strategy is straightforward and adaptable to various deep red dyes and sensing platforms by simply introducing different fluorophores.

A facile route to fabrication of inorganic-small organic molecule cable-like nanocomposite arrays.

A novel and facile method is reported for the preparation of silver iodide-small organic molecule (SOM) cable-like nanocomposites arrays, which involved first the fabrication of SOM nanotubes inside an anodic aluminium oxide (AAO) membrane, and then using the SOM nanotubes in AAO as secondary template to prepare the AgI nanowires in aqueous solution at room temperature.