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A simple heteroleptic iridium­(III) photosensitizer, Ir-1, containing two ligands 5-(trifluoromethyl)-2-phenylpyridine (ĈN–CF3) and bipyridine (N̂N) has for the first time been studied for cocatalyst-free photocatalytic hydrogen evolution (PHE). The complex Ir-1 produces a hydrogen production rate (ηH2) of 3.2 mmol g–1 h–1, which is over 3.6-fold higher than that of the control complex Ir-2 (0.9 mmol g–1 h–1) containing bipyridine and 2-phenylpyridine ligands without CF3 groups. The higher ηH2 of Ir-1 could be ascribed to the high light-harvesting property, longer triplet electron lifetime, and more appropriate driving force for accepting electrons from the sacrificial donor, which enable efficient charge separation and transfer of electrons for hydrogen evolution. Additionally, the photostability issues of Ir-1 and Ir-2 are addressed by the selection of suitable organic solvent/water photocatalytic systems.

New iridium motif linked porphyrin TBPyZnP-Ir is developed for highly efficient photocatalytic hydrogen evolution (PHE) coupled with non-noble-metal cobaloxime co-catalyst.

A class of rhodamine‐based fluorescent sensors for the selective and sensitive detection of Pd2+ metal ions in aqueous media has been developed. A rhodamine‐based sensor PMS and a rhodamine‐BODIPY Förster resonance energy transfer (FRET)‐pair sensor PRS have been incorporated with a piperazine linker and an O−N−S−N podand ligand for specific recognition of Pd2+ ion. Both probes displayed colorimetric and fluorescent ratiometric changes when exposed to Pd2+, due to their spirolactam rings opening and restoring rhodamine conjugation. PRS is highly selective to Pd2+ over 22 other metal ions, showing a 0.6‐fold ratiometric difference at I600nm/I515nm. Additionally, the lactam ring in Pd2+ coordinated PRS‐Pd could be switched back to the closed form in the presence of various thiols, providing a “red‐green traffic light” detection mechanism between red and green emission. Furthermore, PRS showed excellent cell viability and was successfully employed to image Pd2+ and the PRS‐Pd complex ensemble could interchangeably detect biothiols including glutathione (GSH) in A549 human lung cancer cells.

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