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A new family of π-extended BODIPY derivatives were obtained through the condensation of aldehyde and pyrrole in aqueous solution in the presence of HCl. The new rigid π-framework extends beyond the dipyrromethene unit, which is significantly different from classical BODIPYs in the electronic configuration. Both π-extended BODIPYs displayed intense absorption and moderate emission with maxima around 565 and 620 nm, respectively, and showed interesting reactivity toward various nucleophiles. Moreover, these π-extended BODIPYs were developed as fluorescent probes for rapid and selective detection of GSH and were successfully applied for live-cell imaging.

We describe a straightforward, postmodification synthesis for a family of thiophene-fused BODIPY dimers and tetramers through transforming flexible sulfur bridges into coplanar thiophene fusions. FeCl3 was used as a bifunctional oxidant for both intramolecular and intermolecular oxidative aromatic coupling reactions. Oxidative fusion and dimerization gave strong red-shift absorptions from 509 nm for a BODIPY monomer to 830 nm for a tetramer.

Two pyrrolyl-BODIPY dyes with 3,5-di-[Formula: see text]-butyl-4-hydroxyphenyl group were synthesized through stepwise S[Formula: see text]Ar reactions of 3,5-dibromoBODIPYs, which were used as a fluorescent sensor for basic anions. The intermediate pyrrolyl-BODIPYs 2a–2b were regioselectively synthesized through an efficient S[Formula: see text]Ar reaction between 3,5-dibromoBODIPY 1a and pyrroles. The target pyrrolyl-BODIPYs 3a–3b with a 3,5-di-[Formula: see text]-butyl-4-hydroxyphenyl group at 3-position and a pyrrole substituent at 5-position were obtained through a second S[Formula: see text]Ar reaction between pyrrolyl-BODIPYs 2a–2b and high steric hindrance 2,6-dibutylphenol in 90% and 88% yields, respectively. In contrast, the reaction between pyrrolyl-BODIPYs 2a–2b and phenol gave pyrrolyl-BODIPYs 3c–3d with phenoxy substituent at 3-position. These pyrrolyl-BODIPYs 3a–2d show strong, sharp absorptions (551–604 nm) and emissions (564–634 nm) with high fluorescence quantum yields up to 0.86 in dichloromethane. Importantly, the 3,5-di-[Formula: see text]-butyl-4-hydroxyphenyl group of pyrrolyl-BODIPY 3a showed a turn-off fluorescent response toward fluoride anion.

Organic small-molecule fluorescent chromophores have become essential to modern chemical, biological, and materials related investigations. Herein, a straightforward synthesis and subsequent borylation were presented to form a novel family of bisBF2-anchoring acyl-pyridinylhydrazine, which we named BOAPH. The chromophore enjoys outstanding structural diversities owing to varied acyl chlorides and N-heteroarenylhydrazides. These resultant BOAPH dyes are confirmed by NMR, HRMS, and single-crystal X-ray structure analysis. Their spectroscopic properties were studied, and most of the strong absorbance and bright fluorescence with maximum wavelengths centered in the range of 400 and 650 nm. More importantly, they exhibit promising fluorescence quantum yields up to 0.79 in solution and solid states, good photostability, and large Stokes shifts. Furthermore, a respective BOAPH dye with a para-dimethylaminophenyl group exhibited the interesting ability of ultrafast staining and two-photon imaging, which can specifically label lipid droplets of living cells immediately without the need for incubation.

Hypoxia severely impedes the therapeutic efficacies of tumor chemotherapy, radiotherapy and conventional photodynamic therapy (type II PDT). Herein, we proposed a nonplanar near-infrared (NIR)-absorbing hyperthermia and superoxide radical (O2−•) photogenerator (TB) against hypoxic tumors. TB particularly possessed a favorable O2−• generation capability under 808 nm laser irradiation with the donor-acceptor-donor (D-A-D) molecular structure. Moreover, owing to molecular rotation, potent hyperthermia was realized under continuous laser irradiation. For the usage of hypoxic tumor treatment, TB was encapsulated by a block copolymer, poly(ethylene glycol)-b-poly(latic acid) (PEG45-b-PLA24), to fabricate phototheranostic nanoparticles (TB NPs). Due to the twisted molecular structure and the shielding effect of long alkyl chains, the π-π stacking-induced quenching of O2−• could be reduced after the fabrication of nano-assemblies. Significantly, TB NPs exhibited satisfactory O2−• generation for type I PDT and a simultaneously distinct photothermal conversion efficiency (PCE, 62%) for photothermal therapy (PTT) to combat hypoxic tumor cells. Moreover, the high PCE endowed TB NPs with high performance photoacoustic (PA) and photothermal imaging capability. In vivo experiments demonstrated that TB NPs possessed an outstanding phototherapeutic efficacy for eradicating hypoxic tumors. This study established a novel approach for constructing oxygen-independent phototherapeutic reagent against hypoxic tumors.

A new family of N2O-type hydrazine-containing bipyrrole boron complexes has been developed via a one-pot condensation of formylisoindole, hydrazine, and various organoboronic acids. Because of the conformation-restricted coplanar structure and the axial-substituted aryl groups, these novel dyes show deep-red absorption, bright near-infrared (NIR) fluorescence in both solution and solid states, and good solubility in organic solvents. The derivative with pyridinium ions also has been synthesized as an NIR mitochondrially targetable fluorescent probe.

The 1D microwires based on π-extended azaBODIPY were successfully prepared and characterized for the first time. The bisphenanthrene-fused azaBPP-12C with four hydrophobic chains was prepared through de novo synthesis method involving the Suzuki reaction and subsequent oxidative ring-fused coupling. The microwires and aggregation behavior were studied using SEM, XRD and absorption spectroscopy. Finally, an H-type aggregation was confirmed in the solution process.

The direct 3,3'-dimerization of BODIPYs lacking substituent groups in the 1,2,6, and 7 positions was developed by oxidative coupling with FeCl3. This regioselective dimerization was achieved for BODIPYs substituted only in the 5-position with Cl or aryl groups. Further functionalization of the 5,5'-dichloride dimer gave the corresponding pyrrole or 4-(2-aminoethyl)morpholine disubstituted dimers 2f and 2g, respectively. While dimer 2f exhibited intense NIR absorption/emission maxima at 773/827 nm in toluene, dimer 2g showed favorable lysosome-targeting NIR fluorescence in living cells.

Lipid droplets (LDs) have been found to be innate immune first-responders integrating cell metabolism and host defense. The abnormal changes of LDs have been believed to be highly associated with many diseases such as metabolic diseases, cardiovascular disease, viral infections and cancer. Two organic LD-specific nanoprobes have been self-assembled from α-tetraphenyletheneBODIPYs, which exhibited bright near-infrared aggregated state emission with high fluorescence quantum yields up to 0.81 in aqueous system and high photostability, as well as large Stokes shifts up to 130 nm. In the solid powder state, they showed strong NIR fluorescence with red-shifted emission peaks at 700 and 790 nm. The recorded high NIR fluorescence in solid state and in water-induced aggregates can be ascribed to the steric hindrance provided by the TPE groups, which prohibits the π–π interactions of BODIPY planes and avoids the aggregation-caused quenching (ACQ) effect in the BODIPY emission. More importantly, these NIR-emitting nanoprobes exhibit higher LD-specificity than commercial LD-specific BODIPY 493/503 and have been applied for the real-time imaging of intracellular LD and lipid-rich yolk sac of the zebrafish larvae, and monitoring of the LD–lysosome interplay in living cells, which is useful for the early diagnosis of LD-related diseases.

By taking advantage of their intense visible-light absorptions, a photoinduced, AgI promoted oxidative dimerization of BODIPY dyes was developed to give structurally unprecedented α,α- and α,γ-linked dimers. In contrast to classical oxidative aromatic coupling, this methodology does not need a strong oxidant and relies on the singlet electron transfer process between excited-state BODIPYs and an electron acceptor to generate BODIPY based radical species.

Azadipyrromethene derived polycyclic aromatic complexes (HBPs) containing thirteen fused rings have been synthesized, which show highly selective intense absorption in the near infrared spectrum (NIR) region with high photo- and thermo-stability. The periphery alkoxy and alkyl substituents greatly affect their molecular packing structures in thin films and their thin film transistor performances. With the simple changes of the alkyl substituents, the packing structures changed from discrete-grain with H -aggregation type absorption to lamellar packing with J -aggregation type absorption, and the semiconducting properties were modulated from p -type to interesting ambipolar-type in solution-processed organic field effect transistors (OFETs) with hole and electron mobilities reaching to 0.42 and 0.17 cm2 V−1 s−1, respectively.

A photoredox-mediated route to enamination of boron dipyrromethene (BODIPY) dyes with aliphatic amines is reported by activating both the β-C­(sp3)–H bond of amines and the α-C­(sp2)–H bond of BODIPYs under visible light illumination. Dehydrogenation of amines by excited-state BODIPYs and/or photoredox catalyst gave enamine intermediates, which were further trapped by BODIPYs to give a series of α-enamineBODIPYs. These resultant α-enamineBODIPYs showed red-shifted absorption and emission maxima with ratiometric pH-dependent fluorescence.

Photodynamic therapy (PDT) is a minimally invasive technique for the treatment of target malignant tumors via the generation of highly reactive singlet oxygen species. PDT treatment of cancer/tumor tissues greatly relies on the development of suitable stable, highly specific and efficient photosensitizers. BODIPY (Boron dipyrromethene) derivatives, as a class of well-developed, versatile fluorescent dyes, has emerged as a new class of PDT agents over the past decade. Many elegant strategies have been developed to enhance the singlet oxygen generation efficiency and the cancer/tumor cell selectivity of BODIPY-based photosensitizers to improve the therapeutic outcomes as well as to minimize the side effects. Many of the currently reported BODIPY-based photosensitizers are valuable dual imaging and therapeutic agents, which can efficiently generate singlet oxygen for PDT and emit fluorescence for in vivo imaging. Although the currently approved PDT agents used for clinical trials do not feature BODIPYs, this situation is expected to change. In this review, we provide an overview of the various strategies that have been used to improve the singlet oxygen generation efficiency for tuning BODIPY fluorophores into photosensitizers and dual imaging/therapeutic agents. Their photophysical properties and photocytotoxic activity including the absorption/emission wavelengths, the singlet oxygen generation efficiency ([Formula: see text] and the half maximal inhibitory concentration [Formula: see text] of these currently reported photosensitizers are summarized. We believe these newly developed BODIPY-based photosensitizers will broaden current concepts of strategies for PDT agent design, and promise to make an important contribution to the diagnosis and therapeutics for the treatment of cancer.

A new family of pyrrolyl–acylhydrazones anchored with two BF2 units, named BOAPY, have been developed as BODIPY-like and unsymmetrical bis(BF2) chromophores via a simple one-pot reaction. The easil...

Far-red and near-infrared (NIR) absorbing/emitting dyes have found diverse applications in biomedicine and material science. However, the absorption and emission of classical BODIPY chromophores at short wavelength hamper their applications. Several strategies have been adopted to modify the structure of the BODIPY core to design NIR dyes. Among these, the most efficient approach to expand the π-conjugation of the BODIPY core is via fusion of aromatic rings. So far, many novel BODIPY skeletons fused to aromatic hydrocarbons and heterocycles at the b bond have been reported. This review comprehensively describes the recent advances regarding the development of aromatic [b]-fused BODIPY dyes with the focus on the design and synthesis, the relationships between their photophysical/spectroscopic properties and molecular structures, and the potential applications in bioassays and optoelectronic devices.

Here, we report the synthesis of two isomeric BODIPY-based fluorescent molecules with a diethylamino donor group and an acetyl acceptor group at positions 5 and 2 (or 3), respectively, on the boron dipyrromethene core. The structure of the new BODIPY dyes is similar to Prodan, probably the most widely used solvatochromic probe, but with the donor and acceptor groups attached to an electron-poor heteroaromatic core. Interestingly, these BODIPY dyes exhibit unusual spectroscopic and photophysical properties, involving inverse solvatochromic behavior. An in-depth study of the solvent effects and quantum-chemical calculations have been performed to assess the basis for such spectroscopic properties and the effect of the position of the substitution. This work points towards a rational design of new fluorescent probes, based on understanding their spectroscopic and photophysical behavior.

A novel type of dibenzothiophene [b]-fused core-expanded azaBODIPYs were obtained through an efficient post-functionalization of tetrabrominated azadipyrromethenes, using CuI-catalyzed cyclization,...

Subcellular organelle-targeted photosensitizers have recently reported to be effective photodynamic therapy (PDT) agents. In this work, three porphyrin-derived photosensitizers, containing one, two or four triphenylphosphonium targeting groups, were synthesized and characterized by NMR, HRMS, UV-vis and fluorescence spectroscopy. These photosensitizers showed similar photophysical properties to classical porphyrins and exhibited excellent [Formula: see text]O[Formula: see text] quantum yields in acetonitrile. Subcellular colocalization indicated that all three photosensitizers specifically stain the mitochondria of HeLa cells. Photosensitizer mito-dp, containing two triphenylphosphonium cations was found to be the most uptaken by cells and exhibited the best PDT effect with an effective phototoxicity (IC[Formula: see text] (light) [Formula: see text] 12.4 nM), suggestive of a higher practicable potential of mitochondria-targeted PDT agents in cancer therapy.

A family of directly β,γ-linked BODIPY oligomers up to pentamers were regioselectively prepared via Pd(II)-catalyzed oxidative C-H cross-coupling. The structural integrity of β,γ-linked dimers was unambiguously confirmed by X-ray crystallography. These structurally unprecedented oligomers showed red-shifted absorptions and near-infrared emissions along with efficient intersystem crossing, giving ΦΔ in the range of 12-43%, for potential use as heavy-atom-free photosensitizers.

A Cu(I)-promoted oxidative dimerization of BODIPY dyes was developed to give a series of α,α- ethylene-bridged BODIPY dimers and trimers for the first time. This methodology does not need harsh conditions but relies on the singlet-electron-transfer process between alkylated BODIPYs and Cu(I) salt to generate BODIPY-based radical species, which undergo a selective radical homocoupling reaction. Moreover, these resultant dimers and trimers showed high attenuation coefficients, small line widths of the absorption and emission, and intense fluorescence.

In photosensitizers, long triplet excited state lifetimes are key to their efficient electron transfer or energy transfer processes. Herein, we report a novel class of cyclic trimeric BODIPY arrays which were efficiently generated from easily accessible meso-mesityldipyrrinone and arylboronic acids in one pot. Arylboronic acid, for the first time, was used to provide a boron source for BODIPY derivatives. Due to the well-defined and orthogonally aligned BODIPY cores as verified by X-ray crystallography, these BODIPY arrays show strong exciton coupling effects and efficient intersystem crossings, and are novel heavy-atom-free photosensitizers with a long-lived triplet excited state (lifetime up to 257.5 μs) and good reactive oxygen species generation efficiency (up to 0.72) contributed by both 1O2 and O2−˙ under light irradiation., Cyclic BODIPY trimers showed strong exciton coupling in singlet excited states and long-lived triplet excited states, and generated both singlet oxygen and superoxide radicals under light irradiation, giving good reactive oxygen quantum yields and promising PDT results in vitro.

An efficient strategy for building sulfur-bridged oligo-BODIPYs based on the SNAr reaction is described. These oligo-BODIPYs showed broadband and strong visible-near-infrared (NIR) light absorption, strong intramolecular exciton coupling, and efficient intersystem crossing (ISC). Generation of 1O2 as well as O2•- under irradiation was found to give high reactive oxygen species generation efficiencies for those oligomers.

Novel expanded porphyrinoids with advanced structure features (such as multiple-inner-ring-fusion) have a wide range of benefits (such as multi-metal coordination and facile tunable aromaticity) not offered by their normal porphyrin analogues, and have found wide applications as sensors, fluorescent probes, novel ligands and functionalized NIR organic dyes in various research fields. However, the structures of these expanded porphyrinoids are scarce due to their limited synthetic accessibility. Herein, we summarized the lately reported efficient synthesis of novel expanded porphyrinoids with multiple-inner-ring-fusion (up to six-inner-ring-fusion) and smaragdyrins with tunable aromaticity. Their synthesis is either based on an oxidative ring cyclization on linear/macrocyclic oligopyrroles containing N-confused pyrrole unit(s) or a straightforward double SNAr reaction on readily available 3,5-dibromoBODIPY, respectively.

Fluorescent dyes are heavily sought for their potentials applications in bioimaging, sensing, theranostic, and optoelectronic materials. Among them, BODIPY dyes are privileged fluorophores that are now widely used in highly diverse research fields. The increasing success of BODIPY dyes is closely associated with their excellent and tunable photophysical properties due to their rich functionalization chemistry. Recently, growing research efforts have been devoted to the direct functionalization of the BODIPY core, because it allows the facile installation of desired functional groups in a single atom economical step. The challenges of this direct C–H derivation come from the difficulties in finding suitable functionalization agents and proper control of the regioselectivity of the functionalization. The aim of this work is to provide an overview of BODIPY dyes and a summarization of the different synthetic methodologies reported for direct C–H functionalization of the BODIPY framework.

A new synthetic method to build phenanthrene-fused boron dipyrromethenes (BODIPYs) through tandem Suzuki couplings on readily available 2,3,5,6-tetrabromoBODIPYs, followed by an intramolecular oxid...

Organic fluorescent molecules with E/Z isomers usually have different photophysical properties owing to their disparate configurations, which lead to differences in molecular polarity and the chemical environment of atoms. However, due to the difficulty in the synthesis of their pure E and Z conformers, very limited research efforts have been devoted to studying the different photophysical properties of these isomers. In this work, two pairs of pure E/Z isomers of novel fluoroboron acylhydrozone dyes based on 2,2-difluoro-3-[(N-methylpyrrol-2-yl)methylene]-5-phenyl-1,3,4,2-oxadiazaborole (MPOAB) with two different electronic substituent groups (OMe or NEt2) were developed for the first time. These isomers were each characterized by NMR, X-ray structure analysis, HRMS, and absorption and PL spectroscopy. All isomers showed weak fluorescence properties in organic solvents and strong fluorescence in the solid state as well as excellent aggregation-induced emission (AIE) properties. More interestingly, the photophysical properties of the E/Z isomers, especially their aggregation and crystallization-induced emission, are significantly different. These results indicate that the AIE properties of these compounds are mainly attributed to the restriction of single bond rotations between the two aromatic rings and the five-membered fluoroboric ring, while participation of E/Z isomerization is finite. Besides, their photoisomerization, grinding, viscosity, and acid–base fluorescence response properties were also studied. In addition, an isomer of them, as an example, was successfully applied for analyzing the intracellular pH microenvironment of living cancer cells.

Fluorescent probes towards viscosity determination can be used to report on variations in local molecular viscosity and have become valuable tools for the study of intracellular microenvironments. Herein, we develop a family of remarkable meso-2-ketopyrrolyl-derived BODIPY rotors and report a new strategy for building them via simple condensation reactions between oxalyl chloride and substituted pyrroles. They are well characterized by NMR, HRMS, crystal structure, spectroscopic and morphological studies. These uncommon meso-2-ketopyrrolyl-derived BODIPYs are weakly fluorescent in their organic solutions but exhibit bright solid-state red fluorescence from 620 to 661 nm with a maximum fluorescence quantum yield of 25%. All of them also exhibit notable aggregation-induced emission (AIE)-active features. Interestingly, the formed nanoaggregates were observed to exhibit morphological distinctions owing to different substituents. The fluorescence enhancement towards the increased viscosity of the environment might be mainly attributed to the restriction of their intramolecular rotations of the meso-ketopyrrolyl groups. More interestingly, the increase in the fluorescence lifetime of these representative rotors appears to perfectly correlate with the increase in the viscosity of the media, and they have been used as viscosimeters for real-time quantitative determination of the variation of the intracellular viscosity in live cells. The easy synthetic strategy and real-time quantitative determination of the variation pave a new way for creating fluorescent molecular rotor materials.

Oxidative nucleophilic α-hydrogen substitution is a direct method for BODIPY functionalization. However, it was hampered by the low reactivity of BODIPYs toward weak nucleophiles. Herein, we develop a cation radical accelerated oxidative nucleophilic α-hydrogen substitution reaction between BODIPY dyes and a variety of alcohols. This direct C-H alkoxylation presented a wide substrate scope and high site selectivity, providing a series of α-alkoxylated BODIPYs with diverse functional groups. Moreover, a BODIPY derivative with a pyridinium ion was developed as a new mitochondria-targeting fluorescent probe with favorable photophysical properties.

A new family of α, α directly linked bisBODIPYs was developed through a MoCl5-mediated intramolecular oxidative reaction. Due to the coplanar structure of the two conformationally locked BODIPY units, these bisBODIPYs showed well-extended conjugations and gave strong near-infrared absorptions and emissions with maxima around 760 and 780 nm, respectively, with high fluorescence quantum yields of ≤0.84. These dyes were successfully applied for in vitro and in vivo fluorescence imaging by taking advantage of their beneficial photophysical properties.

A phenanthrene-[b]-fused BODIPY exhibited well-defined J-aggregation behavior in both pure hydrocarbon solution and aqueous solution. The highly stable J-aggregates showed narrowed and largely red-shifted absorption with λmax of 840 nm and enhanced molar absorption coefficients (271 000 M−1 cm−1). Encapsulation of J-aggregates within a micellar nanocapsule resulted in nanoparticles that demonstrated good biocompatibility, excellent photothermal stability, high photothermal conversion ability (η ∼ 46.9%) and an effective phototoxicity (IC50 ∼ 2 μg mL−1 in HeLa cells) under 808 nm laser irradiation.

Conjugated molecules with coplanar strong donor and acceptor (D-A) units have been widely used in the design of near-infrared (NIR) photothermal agents to increase an absorption band through intramolecular charge transfer and to control intramolecular motions in aggregated states. However, such conjugated D-A systems have strong dipolar moments and intermolecular interactions, which may inhibit other channels of photothermal conversion and are often susceptible to nucleophiles, especially in the presence of light irradiation. Now, we report a molecular guideline to develop novel NIR organic photothermal nanoagents based on conjugated boron dipyrromethene (BODIPY) oligomers. This oligomerization is helpful not only for their tunable NIR absorptions in the ground state with distinctly redshifted absorption maxima up to 1002 nm and high extinction coefficients but also for their highly efficient photothermal conversion because of the possible motion of the BODIPY motifs around the ethene linked group in the excited state. These oligomers were fabricated as ultra-photostable nanoagents for multiple imaging-guided phototherapies, which efficiently accumulated in tumors, and gave complete tumor ablation with NIR laser irradiation. This strategy of "ground-state conjugation, excited-state rotation" provides a novel guideline to develop advanced theranostic molecules with NIR absorption.

Background and Purpose: Sex hormones affect heart rhythm by regulating ion channels, but the effect of estrogen on cardiac voltage-gated sodium channel in stress-induced pathological conditions is currently not well defined. In this study, we explored the impact of various concentrations of estrogen and the role of its rapid receptor G protein-coupled estrogen receptor (GPER) on sodium channel function in a simulated cardiac stress model of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Experimental Approach: Isoproterenol treated hiPSC-CMs were pre-incubated with various concentrations of β-Estradiol. Their sodium channel electrophysiological function and action potential were dissected by patch clamp and the content of sodium channel was observed by immunohistochemical method combined with laser scanning confocal microscopy. The GPER-specific effect was determined with agonists G1, antagonists G15 and small interfering RNA and sodium channel electrophysiology was selectively detected. Key Results: Isoproterenol-induced stress increased peak sodium current and late sodium current, and shortened action potential duration but the effects of stress were eliminated by β-Estradiol. Pearson Correlation analysis demonstrated no association between estrogenic effects on sodium currents versus content of sodium channel. Activation of GPER produced similar effects as β-Estradiol, while inhibition of GPER cancelled the effects induced by β-Estradiol. Conclusion and Implications: Estrogen through its rapid signal receptor GPER ameliorated the detrimental effects of β-adrenergic overstimulation like in cardiac stress on sodium channel dysfunction in hiPSC-CMs. These results are of great clinical significance as we need to understand the role of sex hormones in cardiovascular disease.

An efficient strategy for the controllable synthesis of BODIPY arrays based on the Stille cross-coupling reaction has been developed, from which a family of well-defined ethene-bridged BODIPY arrays from dimer to hexamer was synthesized. These arrays showed strong absorptions reaching the near-infrared II (NIR II, 1000-1700 nm) region with maxima tunable from 702 nm (dimer) to 1114 nm (hexamer) and possessed efficient light-harvesting capabilities, excellent photostability, and good photothermal conversion abilities under NIR light irradiation.

Two β-formylBODIPYs with strong daylight excitable fluorescence and highly selective visual and colorimetric responses to cyanide anion (CN–) have been prepared. NMR titration experiments have been performed to study the sensing mechanism for these two dyes. Surprisingly, cyanide anion is nucleophilic addition to the α-position of BODIPY core (the azafulvene framework) in aqueous system instead of the expected classical nucleophilic addition to the formyl moiety of the probes. This nucleophilic addition of cyanide anion to the azafulvene framework causes the interruption of the π-conjugation of the BODIPY system, which brings a significant blue-shift (up to 104 nm) of the absorption maxima. A broadened and decreased absorption as well as ratiometrical fluorescence response (with maxima shifts from 523 to 670 nm) were observed with the titration of cyanide anion to probe 1b.

The abnormal change of lipid droplets (LDs) polarity has been believed to be closely associated with many diseases such as fatty liver. Thus, the detection of LDs polarity plays a particular role in the diagnosis of LDs polarity-related diseases. Herein, two isoindole-based fluorescent probes have been derived and they show evident solvatochromic effects, large two-photon absorption cross-section, LDs-specificity, and high photostability and excellent performance in monitoring LDs-polarity changes in living cells. Owing to the existence of intramolecular charge transfer process, these isoindole-based probes exhibited high sensitivity between the emission wavelength maxima and solvent polarity. In spite of that, they maintained high fluorescence quantum yields up to 0.87. Moreover, the detection of LDs-polarity was demonstrated in living cells via confocal laser scanning fluorescence imaging. Importantly, the isoindole-based probe maintained strong fluorescence with high contrast and clarity after seven days of degradation in a zebrafish model, indicating that it is photostable enough and suitable for long-term tracking and observation of biological dynamic changes. All these features render the isoindole chromophore an effective implement for the diagnosis of LDs polarity-related diseases.

NIR photosensitizer is attractive for photodynamic therapy (PDT). Low-power light irradiation and imaging-guided PDT makes it possible to increase tissue penetration depth. The pyrrole-substituted iodinated BODIPY (BDPI) molecule was designed and synthesized, and it possesses an intense NIR absorption and emission band, and exhibits a high singlet oxygen quantum yield (ΦΔ = 0.80) which leads remarkable cytotoxicity upon low power illumination (IC50 = 0.60 μg/mL, 6.1 mW/cm2). After being encapsulated with biocompatibility polypeptide PEG–PLys, polymeric micelles nanoparticles (PBDPI NPs) was obtained that are water-dispersed and passively tumor-targetable. Such enhanced accumulation in tumor area makes it easily traced in vivo due to its NIR fluorescence. In addition, such nanoparticles offer an unprecedented photodynamic therapeutic effect by using a low-power irradiation light, which makes it possible to kill cancer cells in deep tissue efficiently.

Regioselective functionalization of core per-substituted boron dipyrromethenes (BODIPYs) has been achieved efficiently based on tetrabromoBODIPY, which affords a series of dibenzofuran-fused chromophores, via a regioselective nucleophilic substitution reaction followed by direct palladium-catalyzed two-fold intramolecular ring fusion. These rigid dibenzofuran-fused BODIPYs showed impressive photophysical properties such as clearly red-shifted absorption and emission bands, enhanced absorption coefficients upon and intense fluorescence (close to unity).

Two novel quinoxaline-bridged bisBODIPYs have been synthesized by the condensation of 2,3-bis(5-formylpyrrol-2-yl)quinoxaline with 3-ethyl-2,4-dimethylpyrrole followed by a modification using a Knoevenagel reaction. They were well characterized by X-ray diffraction, NMR, HRMS UV-vis and fluorescence spectroscopy. These two quinoxaline-bridged bisBODIPYs have unusual broad absorption bands, which are different from those of typical BODIPYs They exhibit broad red-shifted emission bands centered at around 610 nm and 730 nm respectively with larger Stokes shifts at the range of 1421–2136 cm[Formula: see text] Both bisBODIPYs show different extent solvent-dependent fluorescence and exhibit fluorescence quenching in polar solvents due to the existence of possible intramolecular charge transfer.

A fundamental, highly fluorescent, and easily accessible scaffold named BOPPY is reported. The use of hydrazine as a bridging linkage between pyrrole and N-heteroarenes enables the binding of two BF2 units to provide sufficient rigidity of the unsymmetric core skeleton. These resultant unsymmetrical BOPPYs are thus highly fluorescent in their solutions and solid powder states and exhibit high molar absorption coefficients (42200–47000 M–1 cm–1), large Stokes shifts, excellent photostability, and insensitivity to pH. More importantly, these BOPPYs showed efficient two-photon absorption in the wide spectral range of 700–900 nm, making them well suited for two-photon fluorescence microscopy imaging in living cells.

Three new boron dipyrromethene (BODIPY) dyes substituted with a benzylamino group at the 3-position have been synthesized from halogenated BODIPYs by nucleophilic substitution. The spectroscopic and photophysical properties have been explored in different solvents and have been compared with an analogous 8- benzylaminoBODIPY derivative. The position of the benzylamino group has a significant influence on the spectral band positions, fluorescence quantum yields, and fluorescence lifetimes. The 8- benzylaminoBODIPY emits in the blue range, whereas the 3- substituted shows green fluorescence. Additionally, the extension of the conjugation at the 5-position of 3-benzylaminoBODIPY produces a bathochromic shift of the absorption and emission spectra. The solvent effect on their spectroscopic features has been investigated using the generalized Catalan solvent scales. Quantum-chemical calculations have been performed to assess the effect of the position of the substitution on the spectroscopic properties. Finally, the BODIPY dyes have been employed as probes in fluorescence lifetime imaging of living cells, demonstrating their high potential for bioimaging.

Annularly fused azaBODIPY-based organic fluorophores (HBPs 2) containing up to 13 aromatic ring fusions were synthesized by a Suzuki coupling reaction with bromoazadipyrromethenes and a subsequent regioselective oxidative ring-fusion reaction. X-ray analysis indicates almost planar dipyrrin cores for all crystals but overall curved or “wave” conformations for those HBP dyes. These molecules exhibit unique structural and physical properties including excellent spectral selectivity (negligible absorption between 300 and 700 nm), sharp near-infrared (NIR) absorption (up to 878 nm) and emission (up to 907 nm), large extinction coefficient (up to 4.5 × 105 M–1 cm–1), and excellent photostabilities.

A simple high performance liquid chromatography (HPLC) method was established for identification and quantification of nine polyphenols (gallic acid, chlorogenic acid, caffeic acid, myricetrin, hyperoside, luteoloside, quercitrin-3-rhamnoside, quercetin and kaempferol) in Polygoni Avicularis Herba. The analysis was performed on a Pinnacle II C18 column (250 × 4.6 mm, 5.0 µm) with a gradient elution of an aqueous mobile phase (containing 0.3% acetic acid) modified by acetonitrile. Diode-array detector (DAD) was used to detect the analytes at four wavelengths (270, 326, 355, and 370 nm). The established method was validated with good linearity, precision, accuracy and reproducibility to determine the polyphenols in Polygoni Avicularis Herba. The applicability of this analytical method was confirmed by successful analysis of the herb samples. The results indicated that the contents of these polyphenols varied with different locations of the samples. The anti-oxidation activities of Polygoni Avicularis Herba were further evaluated based on DPPH, ABTS and superoxide anion free radical scavenging assay. The herb exhibited obvious radical scavenging capacity, and gallic acid, chlorogenic acid, myricetrin and hyperoside played important roles in this activity.

An oxidative cross-dehydrogenative coupling of BODIPYs with toluene and its derivatives has been developed, allowing for the facile synthesis of a broad range of structurally diverse α-benzylated BODIPYs. The method exhibits excellent chemoselectivity, affording exclusively α-benzylated BODIPYs in the presence of t-BuOOH and a catalytic amount of Cu(OAc)2. The direct use of readily available toluene and its derivatives as coupling partners avoids unproductive steps for preactivating the functional group installation, and is therefore attractive. Most of the resulting dyes are highly emissive in the solid state due to the introduction of bulky benzyl groups onto the BODIPY core.

A new reaction-based, colorimetric fluorescent sensor of BODIPY derivative ( 1 ) for cysteine (Cys) has been designd and synthesized. This probe shows highly selective detection of Cys over homocysteine (Hcy), glutathione (GSH) as well as other amino acids with a dramatic color change from wine red to fluorescence green because of the significant increase of the visible light excitable fluorescence intensity with the addition of Cys, due to their different reaction rates of the Michael addition reaction. The detection limit for Cys was 8.57 × 10 −7 M. Possible mechanism for sensing of Cys by BODIPY 1 was studied by NMR and HRMS. Probe 1 has been successfully applied to the biological imaging of Cys in living cells.

A set of dipyrrolyldipyrrins have been efficiently synthesized from a direct SNAr reaction on 1,9-dihalodipyrrins with pyrroles and show intense absorption in the NIR region (650–800 nm, as HCl salts). Substituents on both 1,9-dihalodipyrrins and pyrroles greatly affected the reactivity of this SNAr reaction and the absorption properties of the resultant dipyrrolyldipyrrins. These dipyrrolyldipyrrins show sensitive and selective “turn-on” fluorescence response toward Zn2+.

A new substitution pattern of BF2 azadipyrromethene (azaBODIPY) dyes was obtained by phenanthrene fusion through a key palladium-catalyzed intramolecular C–H activation reaction. These [a]-phenanthrene-fused azaBODIPYs have a near planar structure of the phenanthrene-fused azadipyrromethene core in the crystalline state. The chromophore absorbs (log e > 5) and fluoresces (ϕ = 0.32–0.38) strongly above 700 nm with excellent photostability and may be used as an attractive bright NIR bioimaging agent.