Aryl-Boron-Substituted BODIPYs: Direct Access via Aluminum-Chloride-Mediated Arylation from Arylstannanes and Tuning the Optoelectronic Properties

BODIPY-based photocages: rational design and their biomedical application

Photocages, also known as photoactivated protective groups (PPGs), have been utilized to achieve controlled release of target molecules in a non-invasive and spatiotemporal manner. In the past decade, BODIPY fluorophores, a well-established class of fluorescent dyes, have emerged as a novel type of photoactivated protective group capable of efficiently releasing cargo species upon irradiation. This is due to their exceptional properties, including high molar absorption coefficients, resistance to photochemical and thermal degradation, multiple modification sites, favorable uncaging quantum yields, and highly adjustable spectral properties. Compared to traditional photocages that mainly absorb UV light, BODIPY-based photocages that absorb visible/near-infrared (Vis/NIR) light offer advantages such as deeper tissue penetration and reduced bio-autofluorescence, making them highly suitable for various biomedical applications. Consequently, different types of photoactivated protective groups based on the BODIPY skeleton have been established. This highlight provides a comprehensive overview of the strategies employed to construct BODIPY photocages by substituting leaving groups at different positions within the BODIPY fluorophore, including the meso-methyl position, boron position, 2,6-position, and 3,5-position. Furthermore, the application of these BODIPY photocages in biomedical fields, such as fluorescence imaging and controlled release of active species, is discussed.

A series of potent BODIPY photosensitisers featuring tellurophene motifs at boron

This article describes the synthesis and photophysical properties of a series of BODIPY photosensitisers that feature tellurophene motifs appended at the boron centre. These compounds were obtained via nucleophilic substitution of various F-BODIPYs with lithiated tellurophene. The synthetic scope, photophysical characteristics and photosensitisation properties are discussed. Structural modifications around the BODIPY core resulted in an eight-fold improvement in light IC50 values compared to previous designs.

Unsymmetrical Benzothieno-Fused BODIPYs as Efficient NIR Heavy-Atom-Free Photosensitizers

Heavy-atom-free photosensitizers are potentially suitable for use in photodynamic therapy (PDT). In this contribution, a new family of unsymmetrical benzothieno-fused BODIPYs with reactive oxygen efficiency up to 50% in air-saturated toluene was reported. Their efficient intersystem crossing (ISC) resulted in the generation of both 1O2 and O2-• under irradiation. More importantly, the PDT efficacy of a respective 4-methoxystyryl-modified benzothieno-fused BODIPY in living cells exhibited an extremely high phototoxicity with an ultralow IC50 value of 2.78 nM. The results revealed that the incorporation of an electron-donating group at the α-position of the unsymmetrical benzothieno-fused BODIPY platform might be an effective approach for developing long-wavelength absorbing heavy-atom-free photosensitizers for precision cancer therapy.

Strategic Construction of meso-Aryl-Substituted N,N-Carbonyl-Bridged Dipyrrinones as Small, Bright, and Tunable Fluorophores

A series of novel N,N-carbonyl-bridged dipyrrinone fluorophores have been directly constructed from α-halogenated dipyrrinones, which are conveniently obtained from the acid-catalyzed hydrolysis of readily available α,α'-dihalodipyrrins. This novel methodology affords efficient modulation of the functional groups at both the meso- and α-positions of this fluorophore. These resultant dyes show tunable absorption and emission wavelengths, good molar absorption coefficients, relatively large Stokes shifts, and excellent fluorescence quantum yields up to 0.99, and have been successfully applied in both one- and two-photon fluorescence microscopy imaging in living cells.

Synthesis, Properties, and Semiconducting Characteristics of Bisbenzothieno[b]-Fused BODIPYs

A novel family of bisbenzothieno[b]-fused BODIPYs containing seven fused aromatic rings has been developed from readily available benzothieo[3,2-b]pyrroles through an efficient two-step synthetic route, exhibiting planar skeletons with excellent photostabilities, deep-red absorptions, and near-infrared emissions (up to 753 nm). Importantly, the thin-film transistors based on BTB with a meso-dimethylamino-phenyl group exhibit unipolar n-type charge transporting characteristics with a high electron mobility of 0.013 cm2 V-1 s-1.