Tuning the photophysical properties of BODIPY dyes through extended aromatic pyrroles (original) (raw)
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Photophysics of BODIPY Dyes: Recent Advances
Photochemistry and Photophysics - Recent Advances [Working Title]
BODIPY dyes are unique fluorophores that can be used in numerous application areas because of their interesting photophysical properties such as high molar absorptivity, tunable absorption and emission energies, and high fluorescence quantum yields. They show impressive photophysical property changes upon substitution of functional groups on the main core structure. Exchange of the meso-carbon on dipyrrin core with nitrogen produces an analog class of BODIPY called aza-BODIPY. Up to now, various kinds of BODIPY and aza-BODIPY derivatives have been developed and applied in science and industry. In this chapter, recent studies on photophysical properties of BODIPY derivatives are summarized.
Modulation of the photophysical properties of BODIPY dyes by substitution at their meso position
RSC Advances, 2011
We report the photophysical properties of new BODIPY derivatives monosubstituted at the central position. The presence of different functional groups induced the appearance of new photophysical processes in BODIPY dyes, such as intramolecular charge or energy transfer. These phenomena are sensitive to solvent properties (mainly the polarity) and have a potential use as fluorescent probes. Adequate modifications in their molecular structure or in the environment polarity can modulate the emission region of these fluorophores in the visible spectral region. Specifically, different processes and photophysical behaviors can be achieved depending on the excited chromophore and/or the solvent characteristics in a bichromophoric pyrene-BODIPY system.
Synthesis, Photophysical Properties and Solvatochromism of Meso-Substituted Tetramethyl BODIPY Dyes
The 4,4-difluoro-4-bora-3a,4a-diaza-s -indacene fluorescent dyes (BODIPYs) were first synthesized almost 50 years ago; however, the exploration of their technological application has only begun in the last 20 years. These dyes possess interesting photophysical properties, increasing interest in their application as fluorescent markers and/or dyes. Herein, we report the synthesis of tetramethyl BODIPY and four meso-substituted dyes (2-thienyl, 4-pyridinyl, 4fluorophenyl and 4-nitrophenyl derivatives). Their photophysical characterization (absorption spectra, emission spectra, fluorescence quantum yields and time-resolved fluorescence) and solvatochromic behavior were studied. Absorption and emission were barely affected by substituents, with a slightly higher stokes shift observed in the substituted dyes. Substitutions could be associated with a shorter fluorescence lifetime and lower quantum yields. Good correlations were observed between the Catalán solvent descriptors and the photophysical parameters. Also, better correlation was observed between the solvent polarizability descriptor (SP) and photophysical parameters. Overall, only slight solvatochromism was observed. The 4-pyridinyl derivative was the subject of a relatively significant solvatochromism regarding the wavelengths of the emission spectra, with the observation of a bathochromically shifted emission in methanol. The fluorescence quantum yield of the 4-nitrophenyl substituted BODIPY was approximately 30 times higher in hexane, which may be of interest for practical applications.
European Journal of Organic Chemistry, 2010
Nucleophilic substitution reactions of 2-, 3- and 4-hydroxypyridines with 3,5-dibromo meso-aryl and meso-furyl boron-dipyrromethenes (BODIPYs) resulted in the formation of the corresponding 3,5-bis(oxopyridinyl)-BODIPYs and 3,5-bis(pyridinyloxy)-BODIPYs in decent yields. The effect of a pyridone versus an oxypyridine at the 3- and 5-positions on the spectral, electrochemical and photophysical properties were studied as a function of solvent. The 3,5-bis(oxopyridinyl)-BODIPYs exhibit broad, red-shifted absorption and emission bands, decreased quantum yields and lifetimes, displayed large Stokes shifts and easier reductions than did the 3,5-bis(pyridinyloxy)-BODIPYs. The differences in the properties of these two classes of BODIPY dyes are attributed to the extension of π-delocalization associated with the electron-deficient nature of the pyridone groups.
Advanced Materials, 2009
Two-photon absorption (TPA) is a resonant third-order nonlinear optical (NLO) process in which an electron is promoted from its ground state to an excited state by simultaneous absorption of two photons of half-energy in an intense focused light beam such as that generated by a laser source. This phenomenon, theoretically predicted in 1929 by Göppert-Mayer, was experimentally evidenced in 1961 in a TPA-induced fluorescence of Eu 2þ -doped CaF 2 crystals under ruby-laser irradiation. Since then, the intrinsic advantages of TPA excitation, that is, long wavelength and confocal 3D-resolved absorption, led to numerous applications in the fields of material sciences and biology following the availability of tunable laser sources. In particular, the development of femtosecond (fs)-Ti-sapphire lasers triggered numerous studies in the 700-1000 nm spectral range. For instance, TPA was successfully involved in the fabrication of microstructures or high-density optical memories with a 3D sub-micrometer resolution, in signal processing, or for the design of optical limiting devices devoted to the protection of sensors against laser damages. In life sciences, the long-wavelength TPA excitation is located in the biologically transparent spectral range (800-1000 nm), and is therefore able to penetrate more deeply into biological tissues. Combined with the above mentioned spatial resolution, TPA found exciting applications for bioimaging using nonlinear microscopy, and also for drug delivery or dynamic phototherapy. All these applications encouraged the scientific community to design a large variety of chromophores with optimized two-photon cross-sections (s 2 ) in this 700-1000 nm spectral range, such as organic dyes, organometallic or coordination complexes, polymers, dendrimers, or nanonoparticles and quantum-dots, compiled in a recent exhaustive review. However, the near-infrared (NIR) spectral range has been less studied, and in particular the telecommunications-wavelengths spectral range (1.3-1.55 mm), where applications in signal processing (optical power stabilization, pulse suppression, optical limiting) are very attractive. Since 2005, inspired by the Marder-Van Stryland and Osuka-Kim groups, there is a great interest in the design of chromophores exhibiting strong TPA properties in the NIR. Maximal TPA cross-section of ca. 1500 GM at 1.44 mm and 1600 GM at 1.3 mm have been reported for dipolar and quadrupolar squarine-type chromophores, respectively, whereas nickel (bisdithiolene) complexes and singlet diradical systems exhibit significant s 2 over the entire telecommunication range. On the other hand, numerous fused-, extended-, or organizedporphyrin complexes have been reported with very large TPA crosssections ranging from 10 3 to 10 4 GM. Finally, we reported the TPA properties of cyanine-type chromophores (s 2 of 750 GM at 1450 nm) that present enough solubility to carry out additional nonlinear transmittance experiments at telecommunications wavelengths. Herein, we report the synthesis and X-ray structures of aza boron-dipyrromethane (Bodipy) NIR dyes functionalized in the a position by donor-p-conjugated systems, and their TPA and nonlinear transmittance properties in the 1.2-1.6 mm spectral range.
Photophysics of 3,5-diphenoxy substituted BODIPY dyes in solution
Photochemical and Photobiological Sciences, 2007
We have prepared two fluorescent dyes derived from 8-(4-tolyl)-4,4-difluoro-4-bora-3a,4a-diaza-sindacene with phenoxy and (o-bromo)phenoxy substituents at the 3,5-positions by a novel nucleophilic substitution reaction of the corresponding 3,5-dichloroBODIPY analogue. UV-vis absorption, steady-state and time-resolved fluorimetry have been used to investigate their solvent-dependent photophysical properties. The two BODIPY derivatives show narrow absorption and emission bands and display small Stokes shifts. The substituents at the 3,5-positions (phenoxy in 1 and o-bromophenoxy in 2) have a minor effect on the fluorescence quantum yields (0.16-0.40 for 1, 0.17-0.44 for 2) and lifetimes (1.09-2.51 ns for 1, 1.11-2.78 ns for 2). For both compounds, the fluorescence rate constant equals (1.5 ± 0.1) × 10 8 s −1 .
Photochemical Properties and Stability of BODIPY Dyes
International Journal of Molecular Sciences, 2021
The present study is devoted to the combined experimental and theoretical description of the photophysical properties and photodegradation of the new boron-dipyrromethene (BODIPY) derivatives obtained recently for biomedical applications, such as bacteria photoinactivation (Piskorz et al., Dyes and Pigments 2020, 178, 108322). Absorption and emission spectra for a wide group of solvents of different properties for the analyzed BODIPY derivatives were investigated in order to verify their suitability for photopharmacological applications. Additionally, the photostability of the analyzed systems were thoroughly determined. The exposition to the UV light was found first to cause the decrease in the most intensive absorption band and the appearance of the hypsochromically shifted band of similar intensity. On the basis of the chromatographic and computational study, this effect was assigned to the detachment of the iodine atoms from the BODIPY core. After longer exposition to UV light, ...
The Journal of Physical Chemistry A, 2007
Seven fluorescent boradiazaindacene-based compounds with one or two phenyl, ethenylphenyl, and ethynylphenyl substituents at the 3-(or 3,5-) position(s) were synthesized via palladium-catalyzed coupling reactions with the appropriate 3,5-dichloroBODIPY derivative. The effect of the various substituents at the 3-(or 3,5-) position(s) on the spectroscopic and photophysical properties were studied as a function of solvent by means of UV/vis absorption, steady-state, and time-resolved fluorometry, and theoretical modeling. The emission maxima of the symmetrically 3,5-disubstituted dyes are shifted to longer wavelengths (by 30 to 60 nm) relative to the related asymmetrically 3,5-disubstituted ones. Introduction of styryl substituents causes the largest red shift in both the absorption and emission spectra. BODIPY derivatives with ethynylaryl groups also shift the spectral maxima to longer wavelengths compared to aryl-substituted ones but to a lesser degree than the styryl compounds. The quantum-chemical calculations confirm these trends and provide a rationale for the spectral shifts induced by substitution. The fluorescence quantum yields of the ethenylaryl and ethynylaryl analogs are significantly higher that those of the aryl-substituted dyes. The 3,5-diethynylaryl dye has the highest fluorescence quantum yield (∼1.0) and longest lifetime (around 6.5 ns) among the BODIPY dyes studied. The differences in the photophysical properties of the dyes are also reflected in their electrochemical properties where the symmetrically 3,5-disubstituted dyes display much lower oxidation potentials when compared to their asymmetric counterparts. Figure 1. Chemical structures of the BODIPY dyes 1-7. 8588
Synthesis and Optical Properties of Red and Deep-Red Emissive Polymeric and Copolymeric BODIPY Dyes
Chemistry of Materials, 2009
Deep-red emissive polymeric BODIPY dyes (polymers A and B), poly(2,6-BODIPY-ethynylene)s, were prepared by palladium-catalyzed Sonogashira polymerization of 2,6-diiodo-functionalized BODIPY monomers with 2,6-diethynyl-functionalized BODIPY monomers. Poly(2,6-BODIPY-ethynylene)s emit in the deep-red region with emission spectral maxima at around 680 nm and exhibit significant red shifts (up to 163 and 172 nm) of both absorption and emission maxima compared with their initial BODIPY dyes due to significant extension of π-conjugation. Red emissive copolymeric BODIPY dyes (polymers C, D, and E) were also prepared by palladium-catalyzed Sonogashira polymerization of a diethynylfunctionalized BODIPY monomer with 9,9-bis(6′-(hexylthio)hexyl)-2,7-diiodo-9H-fluorene, 1,4-diiodo-2,5-didecyloxybenzene, and 2,5-diiodo-3-decylthiophene, respectively. Incorporation of different band gap monomer units into poly(2,6-BODIPY-ethynylene)s resulted in copolymers with a range of emission wavelengths from 641 to 664 nm. The fluorescence lifetimes of these polymers (polymers AD) are from 2.8 to 3.8 ns except the copolymer with thiophene moieties (polymer E), which displays a much shorter lifetime of 0.23 ns with low fluorescence quantum yield due to efficient intersystem crossing induced by the heavy atom effect of sulfur.