A theoretical and experimental study on the iodination of BODIPY dyes with different degrees of substitution has been developed. Polyhalogenated BODIPYs synthesized in this work are the first ...examples of this type of dyes with more than two halogen atoms in the BODIPY core and they can be selectively functionalized. Surprisingly, the position in which halogen is attached has a marked effect in the photophysical properties and modulates the fluorescence capacity of the resulting BODIPY. These iodinated BODIPYs are efficient singlet oxygen generators.
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New 8-alkenylBODIPYs have been synthesized by Knoevenagel condensation between a series of alkyl-substituted-3,8-dimethylBODIPYs and aromatic or aliphatic aldehydes. This is in clear contrast with ...literature precedents, which indicate that this reaction occurs exclusively on the methyl group at C-3. The change in hybridization of the carbon at the 8-position (from sp3 to sp2) determines the fluorescence emission of the BODIPY, while the presence of electron-donating or -withdrawing groups leads to intramolecular charge transfer processes.
A new library of E‐ and C‐4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) derivatives has been synthesized through a straightforward protocol from commercially available BODIPY complexes, and a ...systematic study of the photophysical properties and laser behavior related to the electronic properties of the B‐substituent group (alkynyl, cyano, vinyl, aryl, and alkyl) has been carried out. The replacement of fluorine atoms by electron‐withdrawing groups enhances the fluorescence response of the dye, whereas electron‐donor groups diminish the fluorescence efficiency. As a consequence, these compounds exhibit enhanced laser action with respect to their parent dyes, both in liquid solution and in the solid phase, with lasing efficiencies under transversal pumping up to 73 % in liquid solution and 53 % in a solid matrix. The new dyes also showed enhanced photostability. In a solid matrix, the derivative of commercial dye PM597 that incorporated cyano groups at the boron center exhibited a very high lasing stability, with the laser emission remaining at the initial level after 100 000 pump pulses in the same position of the sample at a 10 Hz repetition rate. Distributed feedback laser emission was demonstrated with organic films that incorporated parent dye PM597 and its cyano derivative. The films were deposited onto quartz substrates engraved with appropriate periodical structures. The C derivative exhibited a laser threshold lower than that of the parent dye as well as lasing intensities up to three orders of magnitude higher.
Laser vision: The replacement of fluorine atoms at the boron center of commercial 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) by electron‐acceptor moieties (i.e., cyano) is a facile and straightforward route to synthesize highly efficient and photostable laser dyes, which significantly improves the optical performance (see figure).
Nowadays, dye chemistry is a booming area of research. In particular, BODIPY fluorophore dyes are in the spotlight since their chromophore allows the design of tailor-made molecules for specific ...(bio)technological purposes. BODIPY Dyes: A Privilege Molecular Scaffold with Tunable Properties aims to highlight such chemical versatility and modulable photophysical and electrochemical properties. The second and the third chapter deal with BODIPYs in chemosensing and as labels for bioimaging. The fourth chapter focuses on their electroluminescence and redox properties, and their role in photocatalysis. The fifth chapter provides deeper insight into the degradation mechanisms in acid and basic media. The book aims to overview the state of the art of BODIPYs and inspire readers involved in dye chemistry.
Geopolymers may provide a more sustainable alternative to Portland Cement for various possible applications. Geopolymers have attracted particular interest for the immobilization of pollutants, owing ...to their high adsorption capacity, high thermal and chemical resistance, and low leachability. However, practical implementation is currently hindered by a limited understanding of how adsorption processes occur in geopolymers, and how they can be engineered to optimize the incorporation of pollutants and avoid their release. In this work, Molecular Dynamics simulations provide insights into these processes at the atomic scale, studying the role of host material composition and structure in the immobilization of Na and Cs ions. The simulations reveal that the most stable configurations for these ions are near the center of 6- and 8-membered aluminosilicate rings, where the coordination with the geopolymer is maximum. Higher contents of Al and degrees of crystallinity are found to yield more stable configurations for Cs ions, with more favorable adsorption enthalpies and lower diffusion coefficients. The comparison of different crystalline zeolite structures reveals that the framework of sodalite, used as the baseline to develop model geopolymer structures, is the most suitable for the immobilization of Cs since there are no channels and it is formed by small 4- and 6-member, all preventing Cs ions from escaping the cavities.
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The asymmetrically substituted BODIPY dyes 9a and 9b have been synthesized through a key redox step involving the α-nitroso derivative of the starting pyrrol. Both dyes emit fluorescence with quantum ...yields of ca. 0.7, but only 8b behaves as a good laser dye, with an efficiency of 48% in ethanol solution.
Asymmetrically substituted BODIPY analogues of the dye PM567 have been synthesised from 2‐acylpyrroles and pyrroles that bear indene, fluorene or difluorene units. The type of linkage between the ...fluorene and the BODIPY core plays an important role in the photophysics of the BODIPY chromophore. Indeed, an aliphatic bridge gives rise to an energy‐transfer process between the chromophores, whereas a vinyl spacer allows an electronic interaction between them, leading to a large red shift of the spectral bands. The laser action of the new dyes has been analysed under transversal pumping at 10 Hz repetition rate, in both liquid phase and incorporated into solid polymeric matrices. Lasing efficiencies of up to 40 % were reached with high photostabilities with the laser output remaining at the initial level after 1×105 pump pulses in the same position of the sample. The laser action of the new dyes outperforms the laser behaviour of commercial dyes that emit in the same spectral region. The replacement of fluorene by indene quenches the fluorescence and laser emission, but allows the development of an iron cation fluorescent sensor.
It's all under control: A strategy to modulate the photophysical and optical properties of BODIPYs by using asymmetric substitution effects has been developed. New asymmetric BODIPY–indene and BODIPY–fluorene dyes have been synthesized (see figure) by a simple protocol.
“Exclusive Feature Papers in Colorants” is a collection of important high-quality papers (original research articles or comprehensive review papers) published in open access. This Special Issue aims ...to discuss new knowledge or new cutting-edge developments in the colorants research field through selected works, in the hope of making a great contribution to the community. We intend for this issue to be the best forum for disseminating excellent research findings as well as sharing innovative ideas in the field.
In the search for more efficient and photostable solid‐state dye lasers, newly synthesized analogs of the borondipyrromethene (BODIPY) dye PM567, bearing the polymerizable methacryloyloxypropyl group ...at position 2 (PMoMA) or at positions 2 and 6 (PDiMA), have been studied in the form of solid copolymers with methyl methacrylate (MMA). The parent dye PM567, as well as the model analogs bearing the acetoxypropyl group in the same positions, PMoAc and PDiAc, respectively, have been also studied both in liquid solvents and in solid poly(MMA) (PMMA) solution. Although in liquid solution PMoAc and PDiAc have the same photophysical properties as PM567, PDiAc exhibited a photostability up to 10 times higher than that of PM567 in ethanol under 310 nm‐irradiation. The possible stabilization factors of PDiAc have been analyzed and discussed on the basis of the redox potentials, the ability for singlet molecular oxygen O2(1Δg) generation, the reactivity with O2(1Δg), and quantum mechanical calculations. Both PMoAc and PDiAc, pumped transversally at 532 nm, lased in liquid solution with a high (up to 58 %), near solvent‐independent efficiency. This enhanced photostabilization has been also observed in solid polymeric and copolymeric media. While the solid solution of the model dye PDiAc in PMMA showed a lasing efficiency of 33 %, with a decrease in the laser output of ca. 50 % after 60 000 pump pulses (10 Hz repetition rate) in the same position of the sample, the solid copolymer with the double bonded chromophore, COP(PDiMA‐MMA), showed lasing efficiencies of up to 37 %, and no sign of degradation in the laser output after 100 000 similar pump pulses. Even under the more demanding repetition rate of 30 Hz, the laser emission from this material remained at 67 % of its initial laser output after 400 000 pump pulses, which is the highest laser photostability achieved to date for solid‐state lasers based on organic polymeric materials doped with laser dyes. This result indicates that the double covalent linkage of the BODIPY chromophore to a PMMA polymeric matrix is even more efficient than the simple linkage, for its photostabilization under laser operation.
The double covalent linkage of an emitting BODIPY chromophore to a poly(methyl methacrylate) matrix (see scheme) considerably increases the efficiency and the photostability of its laser action, with regard to the corresponding free dye as a solid solution in the same polymer.
Different laser dyes (with special interest in boron dipyrromethene) are incorporated as guests into the channels of zeolite L. The resulting doped material is fully characterized by steady‐state and ...time‐resolved photophysical techniques. The pores of zeolite L are filled with high amounts of dyes, which are exclusively present in their monomeric form and aligned in a preferential orientation, thus generating an organized photoactive material. The ordered disposition of the dye, mostly along the direction of the zeolite L nanochannels, was confirmed by confocal fluorescence microscopy. A careful selection of fluorophores along with controlled loading allows the harvest of light from the entire ultraviolet/visible region for conversion into white light, or alternatively, tuning of the emission in the blue, green, and red regions, owing to the presence of energy‐transfer processes in the antenna systems built up in this work.
Keep your antenna up: The incorporation of laser dyes into the channels of zeolite L gives rise to intermolecular energy‐transfer processes, which form the basis of white‐light‐emitting devices and antenna systems. The doped materials were fully characterized by steady‐state and time‐resolved photophysical techniques. Fluorescence emission bands of these materials cover the entire visible region, and tuning of the emission in the blue, green, and red regions was achieved through energy transfer (see fluorescence images).
