Ruthenium(II)-Catalyzed Sequential C-H/N-H Alkene Annulation Cascade of Phenanthroimidazoles: Synthesis and Photophysical Studies

We report ruthenium(II)-catalyzed sequential C-H/N-H alkenylation cascade of phenanthroimidazole and alkenes to form novel phenanthroimidazoisoindol acrylates via dual C-H activation and aza-Michael reaction. The two nitrogen atoms of the imidazole ring act as directing groups for regioselective dual sequential ortho C-H activation. These polycyclic N-heterocycles were evaluated for their photophysical properties.

A sensitive ratiometric fluorescence probe with a large spectral shift for sensing and imaging of palladium

Palladium (Pd) is an important heavy metal with excellent catalytic properties and widely used in organic chemistry and the pharmaceutical industry. Efficient and convenient analytical techniques for Pd are urgently needed due to the hazardous effects of Pd on the environment and human health. Herein, we have developed five new ratiometric probes for the selective detection of Pd0 based on the Pd-catalyzed Tsuji-Trost reaction. Among them, the F-substituted probe PF-Pd showed the largest spectral shift (148 nm) and the most sensitive response (detection limit 2.11 nM). PF-Pd was employed to determine Pd0 in tap water or lake water samples, which presented satisfactory accuracy and precision. In addition, profiting from its distinct colorimetric response, visual detection of Pd0 was performed on PF-Pd loaded test strips or in field soil samples. Furthermore, fluorescence imaging of living 4T1 cells demonstrated that PF-Pd is suitable for imaging of intracellular Pd0. The good analytical performance of PF-Pd may enable it to be widely used in the convenient, rapid, sensitive and selective detection of Pd0 in environmental or biological analysis.

A novel coumarin-benzopyrylium based near-infrared fluorescent probe for Hg2+ and its practical applications

A novel colorimetric and ratiometric NIR fluorescent probe for Hg²⁺ was designed and synthesized based on a coumarin-benzopyrylium platform. The ring-open form of the probe exhibits NIR absorption (670 nm) and emission (720 nm). The probe shows high sensitivity, high selectivity and rapid response (30 s) to Hg²⁺. The detection limit was as low as 6.94 nM. The probe shows high stability in a wide pH range from 2 to 10. Moreover, the probe can be employed for detecting Hg²⁺ in food and biological samples.