Ready Access to Molecular Rotors Based on Boron Dipyrromethene Dyes-Coumarin Dyads Featuring Broadband Absorption

3-(3-Bromophenyl)-7-acetoxycoumarin

In natural product synthesis, the procurement of easily accessible starting materials is crucial. Chromenones and their subclass, coumarins, are a wide family of small, oxygen-containing aromatic heterocycles. Phenylcoumarins offer a particularly excellent starting point for a diverse chemical space of natural products, and thus are excellent staring materials for more complex natural products. Herein, we report an efficient synthesis of an easily accessible 3-phenylcoumarin bearing two orthogonally substitutable groups, bromine, and an acetyl-protected phenylic hydroxyl group.

A Ratiometric Afterglow Response of Aluminium Ions in Methanol-Water

An afterglow is beneficial as an emission signal in the field of displays and imaging probes. Here, boronic acid-appended and spirolactam ring-containing rhodamine dye 1 was synthesized and grafted onto the surface of room-temperature phosphorescence-active boronate nanoparticles (BPs), composed of polymeric 3-benzo-2,4,8,10-tetraoxa-3,9-diboraspiro[5.5]undecane. The resultant ensemble, 1@BP, exhibited a greenish afterglow. However, the addition of Al³⁺ into the dispersion solution with 1@BP led to a change in the afterglow to grass green as a result of Förster-type energy transfer from the phosphorescent BP to the Al³⁺ -interacting rhodamine dye 1 on the surface. Based on the ratio of the two emission intensities, a linear response in the concentration range of 3.8-15.2 μM was observed, with a detection limit of 4.2 μM for Al³⁺ . A metal ion-dependent discernable color in afterglow was observed on a 1@BP-coated filter paper, which would be useful for not only film-based afterglow chemosensors but also encryption application.