2- and 3-Monohalogenated BODIPY Dyes and Their Functionalized Analogues: Synthesis and Spectroscopy

Unprecedented one-pot sequential thiolate substitutions under mild conditions leading to a red emissive BODIPY dye 3,5,8-tris(PhS)-BODIPY

Phenylthiol performs a thiol exchange with 8-MeS-BODIPY and activates/substitutes the 3,5 positions forming a tri-thiolated BODIPY.

Synthesis of 3-aminoBODIPY dyes via copper-catalyzed vicarious nucleophilic substitution of 2-halogeno derivatives

Copper catalysed vicarious nucleophilic substitution of 2-halogeno BODIPYs with alkyl amines, anilines and an amide produces the corresponding 3-aminoBODIPY derivatives.

Negishi reaction in BODIPY dyes. Unprecedented alkylation by palladium-catalyzed C–C coupling in boron dipyrromethene derivatives

Unprecedented Negishi reaction in haloBODIPYs to yield alkyl, aryl and alkynyl BODIPY dyes, including interesting a symmetrically disubstituted derivatives, is described.

Structural modification strategies for the rational design of red/NIR region BODIPYs

The structure–property relationships of red/NIR region BODIPY dyes is analyzed, so that trends in their photophysical properties can be readily compared.

Thieno-pyrrole-fused BODIPY intermediate as a platform to multifunctional NIR agents

We report the synthesis, photophysical and electrochemical properties, and in vivo fluorescence imaging of a series of new thieno-pyrrole-fused near-infrared (NIR) BODIPY agents by using a versatile intermediate as a building block. The versatile thieno-pyrrole-fused BODIPY intermediate was rationally designed to bear bromo-substituents and absorb in the mid-red region (635 nm) to act as an organic electrophile for the development of NIR multifunctional agents. The use of subsequent palladium-catalyzed and nucleophilic substitution reactions afforded highly conjugated NIR BODIPYs. The novel BODIPYs exhibit long-wavelength absorptions in the NIR region (650-840 nm). The agents produce sharp fluorescence bands, and most of them display respectable quantum yields of fluorescence (0.05-0.87) useful for biomedical imaging, as demonstrated by in vivo imaging with SBDPiR740. Interestingly, a number of agents in the series that are non-halogenated were reactive to O2 at the triplet photo-excited state coupled with a favorable redox potential and decent fluorescence, and hence could be potential candidates for use as photosensitizers in fluorescence-guided photodynamic therapy. Furthermore, the synthetic approach allows further functionalization of the highly conjugated NIR BODIPYs to tune the excited states (PET, ICT) and to conjugate targeting moieties for enhanced biological applications.

Blue-to-orange color-tunable laser emission from tailored boron-dipyrromethene dyes

A series of meso-substituted boron-bipyrromethene (BODIPY) dyes are synthesized and their laser and photophysical properties systematically studied. Laser emission covering a wide visible spectral region (from blue to orange) is obtained by just changing the electron donor character of the heteroatom at position 8. The additional presence of methyl groups at positions 3 and 5 results in dyes with a photostability similar to that of the unsubstituted dye but with much improved efficiency. Correlation of the lasing properties of the different dyes to their photophysical properties provides inklings to define synthetic strategies of new BODIPY dyes with enhanced efficiency and modulated wavelength emission over the visible spectral region.

Synthesis of conjugated BODIPYs via the Wittig reaction

A Wittig reaction was employed to synthesize conjugated BODIPYs in high yields by treating formylated BODIPYs with alkyl/aryl ylides under simple room temperature conditions. Treatment of 3,5-diformyl BODIPYs or α-formyl 3-pyrrolyl BODIPY with different alkyl/aryl ylides in CH2Cl2 at room temperature for 2 h followed by straightforward column chromatographic purification on silica afforded conjugated BODIPYs in ~65-90% yields. This is an alternate method to Knoevenagel and Heck reactions which have been used to synthesize such conjugated BODIPYs. The method works very efficiently, and we prepared 12 substituted BODIPYs including cholesterol-substituted BODIPYs to demonstrate the versatility of the reaction. The spectral, electrochemical, and fluorescence properties of these conjugated BODIPYs are also described.

A turn-on fluorescent sensor for the discrimination of cystein from homocystein and glutathione

We report a turn-on fluorescent sensor based on nitrothiophenolate boron dipyrromethene (BODIPY) derivatives for the discrimination of cystein (Cys) from homocystein (Hcy) and glutathione (GSH). The sensor was applied for detection of Cys in living cells.

Fluorescent indicators based on BODIPY

This critical review covers the advances made using the 4-bora-3a,4a-diaza-s-indacene (BODIPY) scaffold as a fluorophore in the design, synthesis and application of fluorescent indicators for pH, metal ions, anions, biomolecules, reactive oxygen species, reactive nitrogen species, redox potential, chemical reactions and various physical phenomena. The sections of the review describing the criteria for rational design of fluorescent indicators and the mathematical expressions for analyzing spectrophotometric and fluorometric titrations are applicable to all fluorescent probes (206 references).