3-AminoBODIPY dyes: unexpected synthesis from 2-borate derivatives and application as fluorescent probe for alkaline pH range

Catalytic asymmetric C-N cross-coupling towards boron-stereogenic 3-amino-BODIPYs

3-Amino boron dipyrromethenes (BODIPYs) are a versatile class of fluorophores widely utilized in live cell imaging, photodynamic therapy, and fluorescent materials science. Despite the growing demand for optically active BODIPYs, the synthesis of chiral 3-amino-BODIPYs, particularly the catalytic asymmetric version, remains a challenge. Herein, we report the synthesis of boron-stereogenic 3-amino-BODIPYs via a palladium-catalyzed desymmetric C-N cross-coupling of prochiral 3,5-dihalogen-BODIPYs. This approach features a broad substrate scope, excellent functional group tolerance, high efficiency, and remarkable enantioselectivities, under mild reaction conditions. Further stereospecific formation of chiral 3,5-diamino-BODIPYs, along with an investigation into the photophysical properties of the resulting optical BODIPYs are also explored. This asymmetric protocol not only enriches the chemical space of chiroptical BODIPY dyes but also contributes to the realm of chiral boron chemistry.

A novel ratiometric fluorescent sensor from modified coumarin-grafted cellulose for precise pH detection in strongly alkaline conditions

Accurate and convenient monitoring of pH under extreme alkaline conditions is still a challenge. In this work, 4-(3-(7-hydroxy-2-oxo-2H-chromen-3-yl)-3-oxoprop-1-en-1-yl)benzamide (HCB), a coumarin derivative, was grafted onto dialdehyde cellulose (DAC) to obtain a sensor DAC-HCB, which exhibited a ratiometric fluorescent response to the pH of alkaline solutions, resulting in a significant fluorescent color change from yellow to blue (FI459 nm/FI577 nm) at pH 7.5-14. The structure of DAC-HCB was characterized through FT-IR, XRD, XPS, SEM. The pKa of sensor DAC-HCB was 13.16, and the fluorescent intensity ratio FI459 nm/FI577 nm possessed an excellent linear characteristic with pH in the scope of 9.0-13.0. Meanwhile, sensor DAC-HCB showed good selectivity, anti-interference, and fast response time to basic pH, which is an effective fluorescent sensor for examination of pH in alkali circumstance. The recognition mechanism of DAC-HCB to OH- was elucidated with HRMS and density-functional theory (DFT) computational analyses. Sensor DAC-HCB was successfully used for precise detection of environmental water samples pH. This work furnished a new protocol for test strips as a convenient and highly efficient pH detection tool for the high pH environment, and it has great potential for application in environmental monitoring.

The Suzuki–Miyaura reaction of BPin-substituted F-BODIPYs with aryl halides

F-BODIPYs substituted with BPin functionality have been coupled to aryl halides using a mild and efficient catalyst system involving Pd2(dba)3 and XPhos. The methodology enables the Suzuki–Miyaura cross-coupling of electron-rich, electron-poor, and sterically encumbered BPin-substituted F-BODIPYs to aryl halides bearing various functional groups, thus presenting an opportunity for the preparation of highly functionalised F-BODIPYs without need for the corresponding aryl moiety to be available in borylated form.

Silver-mediated direct C–H amination of BODIPYs for screening endoplasmic reticulum-targeting reagents

A highly efficient Ag(i)-mediated direct C–H amination of BODIPYs is accomplished. BODIPYs 3q and 4b exhibit specific ER-targeting capacities.

A versatile quinoxaline derivative serves as a colorimetric sensor for strongly acidic pH

A strongly acidic colorimetric pH sensor induced by the acidity of [Fe(H₂O)₆]³⁺, and single crystal to single crystal transformation between the protonated and deprotonated form.

Synthesis of 2-aminoBODIPYs by palladium catalysed amination

Palladium catalysed amination of a 2-iodoBODIPY with a range of anilines and a primary alkylamine has been used as the basis for a ‘switch-on’ fluorescence sensor for phosgene.

Assembly of BODIPY-carbazole dyes with liposomes to fabricate fluorescent nanoparticles for lysosomal bioimaging in living cells

A strategy was developed to change an ACQ organic dye into a fluorescent nanoparticle probe for lysosomal bioimaging.