BODIPY Molecules Research Articles

Interplay between Theory and Photophysical Characterization in Symmetric α-Substituted Thienyl BODIPY Molecule.

4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based molecules have emerged as interesting materials for optoelectronic applications due to the possibility to easily fine-tune their photophysical and optical properties, dominated by two main absorption bands in the visible range. However, no studies have been reported on the nature of these spectral features. By means of ultrafast spectroscopy, we detect intramolecular energy transfer in a spin-coated film of di-thieno-phenyl BODIPY (DTPBDP) dispersed in a polystyrene matrix after pumping the high-energy absorption band. The same effect is not present upon pumping the lowest-energy band, which instead allows the achievement of efficient amplified spontaneous emission. Density functional calculations indicate the different nature of the two main absorption bands, explaining their different photophysical behavior.

Rational Design of Selenophene‐infused BODIPY Molecules as Fluorogenic Probes for Lung Tumor Imaging – A Computational Approach

AbstractThe BODIPY based molecules show promising properties towards bioimaging applications due to its structural flexibility and versatile optoelectronic characteristic features. Among many strategies in the development of such molecules, fusion of heterocyclic units into the BODIPY core structure is vital in tuning the π‐delocalization and spectral properties. Recently reported Thieno [3,2b] Thiophene based BODIPY (TTB) attracts a lot of attention while the caliber of their Selenophene derivatives are interesting and yet to be explored. Therefore, a systematic replacement of Sulphur by Selenium has been done on TTB and seven new selenophene fused TTB molecules are computationally designed and evaluated for their optoelectronic properties towards bioimaging of CDK2 kinase tumor cells. The optimized geometries indicate that all these molecules are showing excellent π‐delocalization and further stabilized by a range of intra‐molecular C−H−F and B−F−S/Se interactions. Molecular docking studies show that these TTB molecules are potential inhibitors and can be used for lung tumor imaging in biomedical applications. Molecular Dynamics analysis confirms their preferential binding inside the active site up to 100 ns. In summary, this study highlights the importance of Se replacement in designing new BODIPY‐based bioimaging candidates with excellent near‐IR luminescence and photo sensitizers for future biomedical applications.

Electrochemical Diselenation of BODIPY Fluorophores for Bioimaging Applications and Sensitization of 1 O2.

Invited for the cover of this issue are the groups of Holger Braunschweig at the Julius-Maximilians-Universität Würzburg, Germany and Eufrânio N. da Silva Júnior at the Universidade Federal de Minas Gerais, UFMG, Brazil. The image depicts the electrochemical synthesis of selenium-containing BODIPY molecules with lightning symbolizing the electrifying synthetic process, while the surrounding elemental chaos hints at the red-shifted absorption and emission and the transformative photophysical properties of these new compounds. Read the full text of the article at 10.1002/chem.202303883.

Geometry and Chemistry: Influence of Pore Functionalization on Molecular Transport and Diffusion in Solvent-Filled Zirconium Metal-Organic Frameworks.

Postsynthetic modification (PSM) of metal-organic frameworks (MOFs) enables incorporation of diverse functionalities in pores for chemical separations, drug delivery, and heterogeneous catalysis. However, the effect of PSM on molecular transport, which is essential for most applications of MOFs, has been rarely studied. In this paper, we used perfluoroalkane-functionalized Zr-MOF NU-1008 as a platform to systematically interrogate transport processes and mechanisms in solvated pores. We anchored perfluoroalkanes onto NU-1008 nodes by solvent-assisted ligand incorporation (SALI-n, with n = 3, 5, 7, and 9 denoting the number of fluorinated carbons). Transport of a luminescent molecule, BODIPY, through individual crystallites of four versions of methanol-filled SALI-n was monitored by confocal fluorescence microscopy as a function of time and location. In comparison with the parent NU-1008, the diffusivity of the probe molecules within SALI-n declined by 2- to 7-fold depending on chain length and loading, presumably due to the reduction in pore diameter or adsorptive interactions with perfluoroalkyl chains. Atomistic simulations were performed to uncover the microscopic behavior of the BODIPY diffusion in SALI-n. The perfluoroalkyl chains are observed to stay close to the pore walls, instead of extending toward the pore center. BODIPY molecules, which preferably interact with linkers, were pushed to the interior of the channels as the chain length increased, resulting in solvated diffusion and minor differences in the short-time mobility of BODIPY in SALI-n. This suggested that the observed decline of transport diffusivity in SALI-n mainly stemmed from the reduction in the pore size when these flexible chains are present. We anticipate that this proof of concept will assist in understanding how pore functionalization can physically and chemically affect mass transport in MOFs and will be useful in further guiding the design of PSM to realize the optimal performance of MOFs for various applications.

A BODIPY‐Based Molecular Rotor in Giant Unilamellar Vesicles: A Case Study by Polarization‐Resolved Time‐Resolved Emission and Transient Absorption Spectroscopy

AbstractBODIPY and BODIPY‐derived systems are widely applied as fluorophores and as probes for viscosity detection in solvents and biological media. Their orientational and rotational dynamics in biological media are thus of vital mechanistic importance and extensively investigated. In this contribution, polarization‐resolved confocal microscopy is used to determine the orientation of an amphiphilic BODIPY‐cholesterol derivative in homogeneous giant unilamellar vesicles (GUV) made from 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC). The BODIPY‐moiety of the molecule is placed near the polar headgroups, and the cholesterol moiety is embedded in the membrane along the acyl chain of the lipids. The rotational relaxation of fluorophore is conventionally investigated by time‐resolved emission anisotropy (TEA); and this method is also used here. However, TEA depends on the emission of the fluorophore and may not be useful to probe rotational dynamics of the non‐emissive triplet states. Thus, we employ femtosecond transient absorption anisotropy (TAA), that relies on the absorption of the molecule to complement the studies of the amphiphilic BODIPY in DCM and GUV. The photoinduced anisotropy of the BODIPY molecule in DCM decays tri‐exponentially, the decay components (sub‐5 ps, 43 ps and 440 ps) of anisotropy are associated with the non‐spherical shape of the BODIPY molecule. However, the anisotropy decay in homogenous GUVs follows a biexponential decay; which arises from the wobbling‐in‐a‐cone motion of the non‐spherical molecule in the high viscous lipid bilayer media. The observations for the BODIPY‐chol molecule in the GUV environment by TAA will extend to the investigation of non‐emissive molecules in cellular environment since GUV structure and size resembles the membrane of a biological cell.

Antiproliferative activity of meso-substituted BODIPY photocages: Effect of electrophiles vs singlet oxygen

A series of BODIPY compounds with a methylphenol substituent at the meso-position and halogen atoms on the BODIPY core, or OCH3 or OAc substituents at the phenolic moiety was synthesized. Their spectral and photophysical properties and the photochemical reactivity upon irradiation in CH3OH were investigated. The molecules with the phenolic substituent at the meso-position undergo more efficient photo-methanolysis at the boron atom, while the introduction of the OCH3 group at the phenolic moiety changes the reaction selectivity towards the cleavage at the meso-position. The introduction of the halogen atoms into the BODIPY increases the photo-cleavage reaction efficiency, as well as the ability of the molecules to sensitize oxygen and form reactive oxygen species (ROS). The efficiency of the ROS formation was measured in comparison with that of tetraphenylporphyrin. The antiproliferative effect of BODIPY molecules was investigated against three human cancer cell lines MCF-7 (breast carcinoma), H460 (lung carcinoma), HCT116 (colon carcinoma), and two non-cancer cell lines, HEK293T (embryonic kindey) and HaCaT (keratinocytes), with the cells kept in the dark or irradiated with visible light. For most of the compounds a modest or no antiproliferative activity was observed for cells in the dark. However, when cells were irradiated, a dramatic increase in cytotoxicity was observed (more than 100-fold), with IC50 values in the submicromolar concentration range. The enhancement of the cytotoxic effect was explained by the formation of ROS, which was studied for cells in vitro. However, for some BODIPY compounds, the effects due to the formation of electrophilic species (carbocations and quinone methides, which react with biomolecules) cannot be disregarded. Confocal fluorescence microscopy images of H460 cells and HEK293T show that the compounds enter the cells and are retained in the cytoplasm and membranes of the various organelles. When the cells treated with the compounds are irradiated, photo-processes lead to cell death by apoptosis. The study performed is important because it provides bases for the development of novel photo-therapeutics capable of exerting photo-cytotoxic effects in both oxygenated and hypoxic cells.

Novel BODIPY Conjugates with Myrtenol: Design, Spectral Characteristics, and Possibilities for Practical Application

The synthesis of new fluorescent probes, based on biocompatible luminophors and exhibiting various specificities, is intensively developed worldwide. Many luminophors contain a hydrophobic group that limits their application for cell staining under vital conditions. Herein, we report the synthesis of two BODIPY molecules—BF2-meso-(4-butan/pentanamido-N-(((1S,5R)-6,6-dimethylbicyclo [3.1.1]hept-2-en-2-yl)methyl)-N,N-dimethylpropan-1-aminium)-3,3′,5,5′-tetramethyl-2,2′-dipyrromethene bromides—designed as 10, 11 with a spacer of either four or three CH2 groups in length, respectively. These molecules present conjugates of BODIPY luminophors with (+)-myrtenol via a quaternary ammonium group. Both terpene-BODIPY conjugates demonstrated high fluorescence efficiency in various solvents such as OctOH, DMSO and water, and were characterized by their stability at pH 1.65–9.18. The fusion of the myrtenol, a monocyclic terpene, to the BODIPY fluorophore in the meso-substituent facilitated their penetration into the filamentous fungi Fusarium solani, while impairing the binding of the latter with S. aureus, K. pneumoniae and P. aeruginosa. The additional quaternary ammonium group between the myrtenol and fluorophore moieties restored the bacterial cell-staining while it did not affect the staining of fungi. Finally, the BODIPY conjugate 11 was able to stain both Gram-positive and Gram-negative bacteria by its interaction with their cell wall (or the membrane), as well as penetrating into filamentous fungi F. solani and staining their mitochondria.

Cover Picture: Synthesis, Crystal Structure, and Photophysical Properties of Mono‐ and Di‐Nuclear Palladium BODIPY Chromophores (BKCS 5/2023) Gajendra Gupta, Junseong Lee, Chang Yeon Lee

BODIPY‐based complexes have proven to be an efficient photosensitizer for generating singlet oxygen essential for several significant applications. This article describes a method of utilizing mononuclear and dinuclear palladium‐based BODIPY molecules under visible light irradiation to generate singlet oxygen (1O2) for application in photocatalysis. More details are available in the article by Lee et al. image

A BODIPY-based fluorescent chemosensor with 2, 6-substitution for visual and highly selective detection of S2–

BODIPY derivatives have often been employed as fluorescent sensors to probe toxic ions in environment and living systems, such as sulfide ion (S2−). Whilst many structure modifications have been exploited on groups at the 3, 5, 8-positions, there are quite few examples on tailoring the 2,6-substituents for chemosensor investigations. Herein, we design and synthesize a 2,6-substituted BODIPY molecule, LM-BDP, to use as a fluorescent probe for detecting S2− in aqueous media. The electronic and crystal structures of the probe are studied by density functional theory (DFT) calculations and single-crystal X-ray diffraction analysis. Spectroscopy investigations are performed in a variety of conditions, showing that LM-BDP exhibits a noticeable color change from pink to dark red and a fluorescence shift from yellow to pink channel with decreased intensity upon addition of S2−. The selectivity and sensitivity measurements show that LM-BDP can only response to S2− with a detection limit of 0.29 μM in less than 100 s. The remarkable contrast in fluorescence images in test-stripe and RAW 264.7 cell experiments indicates that the probe is a proper candidate for the application in detecting exogenous S2−.

Surface regulation by bifunctional BODIPY to fabricate stable CsPbBr3 for multi-layered optical anti-counterfeiting

Cesium lead halide perovskite quantum dots (QDs) have attracted immense attention for luminescent materials due to their narrow emission bands and color-tunable emission. However, indispensable surface ligands originating from ligand-assisted synthesis strategies severely deteriorate the stability and luminescence properties of QDs since these ligands have a highly dynamic binding. Herein, we used a green fluorescence BODIPY molecule containing thiol (named SH-BDP) to regulate the CsPbBr3 QDs surface by ligand regulation. Density functional theory calculations proved that the SH-BDP molecule could bind to the exposed Pb of CsPbBr3 QDs stronger than traditional ligands to form stable SH-BDP-QDs. Moreover, the SH-BDP fixed on the CsPbBr3 QDs surface can improve water and light resistance. It also served as a knob to tune their luminescence properties and the reversible thermal-stimuli response. Finally, the multi-response property of SH-BDP-QDs was realized under polar solvent or heat along with UV light. In addition, we used the SH-BDP-QDs to create various anti-counterfeiting labels; several luminous modes were achieved under different external stimuli, which improved the quality of the optical anti-counterfeiting labels and ensured information security. This work indicates the immense potential of surface ligand manipulation in improving the stability and multi-stimuli-responsive optical encoding of perovskite quantum dots.

Endowing deep-red BODIPY luminophors with enhanced aggregation-induced emission by installing miniature rotor of trifluoromethyl for solution-processed OLEDs

Highly efficient deep-red (DR) organic materials in aggregated state are fundamentally restricted by the serious nonradiative decay rates (k nr ) due to the energy gap law, and the aggregation induced quenching in view of significant intermolecular interaction. Here, two new BODIPY chromophores owning donor−acceptor−donor (D−A−D) structure, namely CF 3 -2TPA and 2CF 3 -2TPA, were designed and synthesized. Trifluoromethyl (CF 3 )-substituted phenyl group was introduced to the meso-position of the BODIPY core, tuning red to DR emission and suppressing intermolecular interaction with the utilization of the steric hindrance of CF 3 . Besides, CF 3 -2TPA and 2CF 3 -2TPA show enhanced aggregation-induced emission (AIE) characteristic, which was ascribed to the CF 3 rotor dissipating the excited-state energy. The OLEDs are fabricated by combining a thermally assisted delayed fluorescence host with a deep-red dye, showing a DR cut-on wavelength of 668 nm and external quantum efficiency of 2.3%. This work provided a rotor strategy to convert BODIPY molecule with obvious AIE property, providing their promising applications in DR-OLEDs. The miniature rotor of trifluoromethyl (CF 3 ) introduced to the meso-position of BODIPY, induced redshifted to deep-red emission, prevented obvious intermolecular interaction and achieved remarkably enhanced aggregation induced emission feature. Deep-red OLED showed an emission wavelength of 668 nm and an EQE max of 2.3%. • The CF 3 units, modifying the meso position of BODIPY, assisted in the deep-red emission. • Depending on the steric hindrance of CF 3 groups, the intermolecular interaction and packing were suppressed. • The enhanced AIE feature of BODIPYs was realized due to the miniature rotor of CF 3 substitutes. • Deep-red OLED showed an emission wavelength of 668 nm and an external quantum efficiency of 2.3%.

Design of the novel calix[n]BODIPY molecules (n = 4–8): TDDFT and AIM study

Design of the novel calix[n]BODIPY molecules (n = 4–8): TDDFT and AIM study

BODIPY-linked conjugated porous polymers for dye wastewater treatment

As a new family of functional porous materials, conjugated porous polymers (CPPs) with tuneable porosities and molecular architectures show great potentials in adsorption, light harvesting, and catalysis applications. This paper describes the incorporation of strong visible-light absorbing BODIPY molecules into the skeleton of CPPs via Sonogashira coupling reactions. The obtained CPPs displayed integrated properties of high surface area, hierarchical porous structures and strong visible-light absorption. As a result, the CPPs showed relatively high adsorption capacity and high photocatalytic degradation efficiency towards organic dyes. Mechanism studies revealed that the CPPs enabled the generation of singlet oxygen species under light irradiation, accounting for the main driving force for the dye degradation. This study provides a new route for the development of organic adsorbents and photocatalysts for water treatment and purification. • Conjugated porous polymers consisting of BODIPY skeletons were synthesized. • The CPPs demonstrated hierarchical porosity and strong visible light absorption. • The CPPs showed high adsorption capacity towards organic dyes in aqueous solution. • The CPPs can be used as photosensitizers for photodegradation of organic dyes.

Conjugate of meso-carboxysubstituted-BODIPY with thioterpenoid as an effective fluorescent probe: Synthesis, structure, spectral characteristics, and molecular docking

This paper is devoted to the design of a fluorescent probe based on meso-carboxysubstituted-BODIPY with a thioterpene fragment. The functional replacement of the methoxy group in the BODIPY molecule on a thioterpene fragment was carried out in order to find out the antiplatelet and anticoagulant action mechanisms of thioterpenoids and to assess the membrane and receptor factors contributions. The molecular structure of the conjugate was confirmed via UV/vis-, NMR- and MS-spectra. It is found that the probe is a high fluorescence quantum yield (to ∼ 100%) in the blue-green region at 509–516 nm. Molecular docking of all studied molecules showed that the BODIPY with terpenoid conjugation is an excellent way to increase their affinity to platelet receptor P2Y12.

Fluorescence quenching-based bodipy-boronic acid linked viologen dual system for potential glucose sensing applications

PurposeThe purpose of this study is to develop a non-enzymatic based glucose-sensing platform composed of Bodipy-BBV dual system which can be monitored by a photodetector under the blue LED excitation.Design/methodology/approachThe sensor has been developed from a dual system including a fluorescent dye, an aldehyde derivative of boron dipyrromethene (Bodipy) and a quencher, orto-boronic acid linked viologen (o-BBV) where their combination resulted in a ratiometric fluorescence quenching in ethanol: PBS (1:1, pH:7.4) solution under UV light excitation. By glucose addition, o-BBV has been released from the Bodipy and binded to cis-diol groups of glucose, thereby fluorescence emission of Bodipy has been regained. Furthermore, a setup consisting of a light emitting diode (LED) and a photodiode (PD) was used to prove electrical detection of glucose without the need for expensive and bulky optical equipment, enabling the development of a miniaturized and low-cost glucose-sensing platform.FindingsThe fluorescence intensity of the Bodipy derivative in the solution (2 × 10−6 M) was diminished by 93% in the presence of o-BBV solution (5 × 10−3 M). Upon the glucose addition, 81% of the Bodipy fluorescence intensity has been recovered after introduction of 30 mM of glucose, where the ratio of o-BBV/Bodipy was 35:1. A linear response between 10 and 30 mM glucose concentration was obtained, which covers the biologically significant range. A high correlation between the photodiode current and Bodipy fluorescence intensity was achieved.Originality/valueEven though Bodipy molecules are known with their superior optical properties and applied to the fluorescence-based detection of glucose, to the best of the authors’ knowledge, no work has been reported on Bodipy-BBV dual system to detect glucose molecules as a non-enzymatic based method. This design enables the dye and the quencher to independently coexist in the solution, allowing for tuning of their individual concentrations to optimize the glucose sensitivity. Furthermore, an electrical light detection scheme consisting of a LED and a photodiode has been implemented to eliminate the bulky optical equipment from the measurement setup and further this work for the development of a compact and inexpensive sensor. The results presented here demonstrate the feasibility of this system for the development of a novel glucose sensor.

TDDFT and AIM evaluation of the effect of H and F abstraction from the calix[8]BODIPY molecule

Exploring the structures, electronic and optical properties of the calix[8]BODIPY and other similar structures is subject of this research. As the result no imaginary frequency and high cohesive energies per atoms was found for these designed structures. As the result of -H or -F abstraction from the upper part of calix[8]BODIPY, narrowing of the Eg was observed. Significant enhancements of the intensity of absorption (epsilon) in visible region was seen as the result of individual H or F atoms separation or both of them from the calix[8]BODIPY molecule. Improvement of absorption intensity and the red-shifting in their absorption wavelength was seen in presence of water as solvent. Finally the strong hydrogen bonding in lower part of the calix like molecules was confirmed by AIM calculations.

New series of BODIPY dyes: Synthesis, characterization and applications in photovoltaic cells and light-emitting diodes

We report on the straightforward synthesis, characterization and photovoltaic and light-emission applications of two series of BODIPY molecules with aryloxy or alkoxy groups bonded to the boron centre. The crystal structures of two of these new dyes are also presented. The BODIPYs have absorption features similar to those of the analogous boron-fluorinated BODIPYs used as starting materials. However, the fluorescence properties vary significantly with the nature of the aryloxy/alkoxy group. The photovoltaic performance in bulk heterojunction solar cells of the newly synthesized compounds does not, however, outperform that of the parent boron-fluorinated BODIPYs. The maximum power conversion efficiency was obtained with two non-fluorescent BODIPYs, reaching 0.9%, compared with 2.79% obtained for the cells based on the corresponding boron-fluorinated precursor. The fluorine replacement by aryloxy/alkoxy groups had instead a positive effect on the light-emitting properties of the compounds of one of the series, leading to higher maximum luminance (114 cd/m2) and efficiency (0.057 cd/A), compared to devices based on the corresponding boron-fluorinated dye (35 cd/m2 and 0.015 cd/A, respectively).

Fluorescence Quenching of 3,5-Diphenyl-8-CF3-BODIPY Luminophores Bearing Aminophenyl Substituents by Aromatic Molecules

It has been found that the fluorescence quantum yield of 3,5-diphenyl-8-CF3-BODIPY luminophores with aminophenyl substituents in aromatic solvents strongly depends on the position of the aniline amino group with respect to the position of attachment to the core of the BODIPY molecule. It has been suggested and substantiated that the reason for quenching of BODIPY meta-isomers is the specific interaction of luminophore molecules with aromatic molecules.

BODIPY dimers: structure, interaction, and absorption spectrum

The object of the present study are BODIPY molecules obtained previously by Piskorz et al. (Dyes Pigm. 178:108322, 2020) for their antimicrobial activity. Structural analysis of the BODIPY dimers is presented in context of the aggregation influence on the photophysical properties. The thorough investigation of the nature of intermolecular interaction in the representative BODIPY dimers is provided together with the decomposition of the interaction energy into the components of well-defined origin according to SAPT procedure. For the model BODIPY systems the careful examination of the interaction nature for the dimer structure based on experimental crystal study as well as fully optimized is given. The tendencies observed in the model dimers are further on investigated for two pairs of BODIPY systems designed for biomedical application. The analyzed molecules are shown to maximize the mutual interaction by the optimization of the stacking dispersion contacts between the aromatic rings of the molecules, therefore producing stable dimers. The estimation of SAPT0 interaction energy components confirms the dominating dispersion character arising from mutual BODIPY core contacts. The influence of the dimerization process on the photophysical properties of the systems studied theoretically depends to the high extend on the dimerization mode and is significant for parallel and antiparallel dispersion-governed dimers.

A carrier-free multifunctional nano photosensitizer based on self-assembly of lactose-conjugated BODIPY for enhanced anti-tumor efficacy of dual phototherapy

We reported a simple strategy for constructing carrier-free multifunctional NPSs based on one single amphiphilic small molecule of glycosylated BODIPY for tumor targeting and microenvironment responsive DPT with enhanced anti-tumor efficacy. • A multifunctional nano photosensitizer assembled from a glycosylated BODIPY. • Excellent biocompatibility, targetability, and GSH responsiveness in vitro. • Biosafety, accumulation at tumors and effective destruction of tumors in vivo. Carrier-free multifunctional nano photosensitizers (NPSs) based on amphiphilic small molecules with a single photoactivable motif that combine targeted delivery, tumor microenvironment (TME) responsive release, and dual phototherapy with a single irradiation hold great potential to enhance efficacy, safety, and accuracy of cancer treatment as well as facilitate clinical translation. However, the fabrication of such NPSs is challenging. Herein, we report the synthesis of an amphiphilic small glycosylated BODIPY (BSL) molecule with the ability of self-assembly into NPS (BSL NPS). BSL NPS shows excellent biocompatibility, targetability to HepG2 cells via overexpressed galactose receptors on the cell membrane, and responsiveness to high level of glutathione (GSH) in TME. BODIPY released from intracellular BSL NPS by GSH generated reactive oxygen species and hyperthermia upon irradiation of 685 nm NIR laser resulted in significant enhanced cytotoxicity through the synergy of photodynamic and photothermal therapies. More importantly, in vivo experiments with BSL NPS using HepG2 tumor-bearing nude mice model demonstrated good biosafety, enrichment at tumors, and effective destruction of tumors. This work provides a good example of constructing carrier-free multifunctional NPSs based on one single glycosylated amphiphilic small molecule for dual phototherapy against cancers, which may eventually contribute to bridging the translational gap to the clinic.