Excited-State Dynamics in Borylated Arylisoquinoline Complexes in Solution and in cellulo

Two four-coordinate organoboron N,C-chelate complexes with different functional terminals on the PEG chains are studied with respect to their photophysical properties within human MCF-7 cells. Their excited-state properties are characterized by time-resolved pump-probe spectroscopy and fluorescence lifetime microscopy. The excited-state relaxation dynamics of the two complexes are similar when studied in DMSO. Aggregation of the complexes with the carboxylate terminal group is observed in water. When studying the light-driven excited-state dynamics of both complexes in cellulo, i. e., after being taken up into human MCF-7 cells, both complexes show different features depending on the nature of the anchoring PEG chains. The lifetime of a characteristic intramolecular charge-transfer state is significantly shorter when studied in cellulo (360±170 ps) as compared to in DMSO (∼960 ps) at 600 nm for the complexes with an amino group. However, the kinetics of the complexes with the carboxylate group are in line with those recorded in DMSO. On the other hand, the lifetimes of the fluorescent state are almost identical for both complexes in cellulo. These findings underline the importance to evaluate the excited-state properties of fluorophores in a complex biological environment in order to fully account for intra- and intermolecular effects governing the light-induced processes in functional dyes.This work was supported by the European Union (via the ITN LogicLab funded under the Horizon 2020 research and innovation program under the grant agreement No 813920). We thank Prof. Dr. Rainer Heintzmann and Dr. Benedict Diederich for providing BioLab facilities and supporting the image acquisition. The ELYRA 7 (used for producing Figure 3 and S8) was funded by the Free State of Thuringia with grant number 2019 FGI 0003 and supported by the Microverse Imaging Center (funded by the DFG under Germany Âs Excellence Strategy �R EXC 2051 �R Project-ID 390713860). We further acknowledge funding by the DFG (Project number 316213987 – SFB 1278, INST 1757/25-1 FUGG), the Free State of Thuringia (TAB, TMWWDG, AdvancedSTED/2018 FGI 0022; Advanced Flu-Spec/ 2020 FGI 0031), BMBF (Photonics Research Germany (FKZ; 3N15713/13N15717) integrated into the Leibniz Center for Photonics in Infection Research (LPI)) and the innovation program by the German BMWi (ZIM; project 16KN070934 / Labon- a-chip FCS-Easy). The Spanish Ministerio de Ciencia e Innovación (grants PID2020-119992GB-I00, PID2019-106358GBC21, and PID2019-106358GB-C22), the Consejo Superior de Investigaciones Científicas (grant 202080I005 for A.R.), and the Junta de Andalucía/University of Huelva (grant UHU-202070) are thanked for financial support. We thank Dr. Z. Dom Nguez for assistance in the early stage of this project. Open Access funding enabled and organized by Projekt DEAL

An All-Photonic Molecule-Based Parity Generator/Checker for Error Detection in Data Transmission

The function of a parity generator/checker, which is an essential operation for detecting errors in data transmission, has been realized with multiphotochromic switches by taking advantage of a neuron-like fluorescence response and reversible light-induced transformations between the implicated isomers

A supramolecular keypad lock

The reversible photoswitching between an anthracene derivative and its [4+4] dimer, using the template effect of the CB8 macrocycle, was demonstrated. This example of supramolecular chemistry in water was harnessed to demonstrate the operation of a keypad lock device that is driven by means of light and chemicals as inputs

Molecular Implementation of Sequential and Reversible Logic Through Photochromic Energy Transfer Switching

Photochromic spiropyrans modified with fluorophores were investigated as molecular platforms for the achievement of fluorescence switching through modulation of energy transfer. The dyads were designed in such a way that energy transfer is only observed for the open forms of the photochrome (merocyanine and protonated merocyanine), whereas the closed spiropyran is inactive as an energy acceptor. This was made possible through a deliberate choice of fluorophores (4-amino-1,8-naphthalimide, dansyl, and perylene) that produce zero spectral overlap with the spiro form and considerable overlap for the merocyanine forms. From the Förster theory, energy transfer is predicted to be highly efficient and in some cases of 100 % efficiency. The combined switching by photonic (light of λ>530 nm) and chemical (base) inputs enabled the creation of a sequential logic device, which is the basic element of a keypad lock. Furthermore, in combination with an anthracene-based acidochromic fluorescence switch, a reversible logic device was designed. This enables the unambiguous coding of different input combinations through multicolour fluorescence signalling. All devices can be conveniently reset to their initial states and repeatedly cycled

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

[EN] Four new dyes that derive from borylated arylisoquinolines were prepared, containing a third aryl residue (naphthyl, 4-methoxynaphthyl, pyrenyl or anthryl) that is linked via an additional stereogenic axis. The triaryl cores were synthesized by Suzuki couplings and then transformed into boronic acid esters by employing an Ir(I)-catalyzed reaction. The chromophores show dual emission behavior, where the long-wavelength emission band can reach maxima close to 600 nm in polar solvents. The fluorescence quantum yields of the dyes are generally in the range of 0.2¿0.4, reaching in some cases values as high as 0.5¿0.6. Laserflash photolysis provided evidence for the existence of excited triplet states. The dyes form fluoroboronate complexes with fluoride anions, leading to the observation of the quenching of the long-wavelength emission band and ratiometric response by the build-up of a hypsochromically shifted emission signal.Funding by the Spanish Ministry of Economy, Industry, and Competitiveness (CTQ2014-54729-C2-1-P for U.P., CTQ2013-48164-C2-1-P and CTQ2013-48164-C2-2-P for A.R., Ramon y Cajal contracts RYC-2013-12585 for A.R. and RYC-2015-17737 for I.V.), the Spanish Ministry of Science, Innovation, and Universities (CTQ2017-89832-P for U.P., CTQ2016-78875-P for M.C.J., and CTQ2017-89416-R for I.V.), the European Research and Development Fund, and the Andalusian Government (2012/FQM-2140 for U.P., 2009/FQM-4537 and 2012/FQM-1078 for A.R) is gratefully acknowledged.Pais, VF.; Neumann, T.; Vayá Pérez, I.; Jiménez Molero, MC.; Ros, A.; Pischel, U. (2019). Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence. Beilstein Journal of Organic Chemistry. 15:2612-2622. https://doi.org/10.3762/BJOC.15.254S2612262215Frath, D., Massue, J., Ulrich, G., & Ziessel, R. (2014). Lumineszierende Materialien: Fixierung von π-konjugierten und heterocyclischen Liganden mit Bor(III). Angewandte Chemie, 126(9), 2322-2342. doi:10.1002/ange.201305554Ji, L., Griesbeck, S., & Marder, T. B. (2017). Recent developments in and perspectives on three-coordinate boron materials: a bright future. Chemical Science, 8(2), 846-863. doi:10.1039/c6sc04245gVanga, M., Lalancette, R. A., & Jäkle, F. (2019). Controlling the Optoelectronic Properties of Pyrene by Regioselective Lewis Base‐Directed Electrophilic Aromatic Borylation. Chemistry – A European Journal, 25(43), 10133-10140. doi:10.1002/chem.201901231Alcaide, M. M., Santos, F. M. F., Pais, V. F., Carvalho, J. I., Collado, D., Pérez-Inestrosa, E., … Pischel, U. (2017). Electronic and Functional Scope of Boronic Acid Derived Salicylidenehydrazone (BASHY) Complexes as Fluorescent Dyes. The Journal of Organic Chemistry, 82(14), 7151-7158. doi:10.1021/acs.joc.7b00601Bozdemir, O. A., Guliyev, R., Buyukcakir, O., Selcuk, S., Kolemen, S., Gulseren, G., … Akkaya, E. U. (2010). Selective Manipulation of ICT and PET Processes in Styryl-Bodipy Derivatives: Applications in Molecular Logic and Fluorescence Sensing of Metal Ions. Journal of the American Chemical Society, 132(23), 8029-8036. doi:10.1021/ja1008163Niu, L.-Y., Guan, Y.-S., Chen, Y.-Z., Wu, L.-Z., Tung, C.-H., & Yang, Q.-Z. (2012). BODIPY-Based Ratiometric Fluorescent Sensor for Highly Selective Detection of Glutathione over Cysteine and Homocysteine. Journal of the American Chemical Society, 134(46), 18928-18931. doi:10.1021/ja309079fZheng, Q., Xu, G., & Prasad, P. N. (2008). Conformationally Restricted Dipyrromethene Boron Difluoride (BODIPY) Dyes: Highly Fluorescent, Multicolored Probes for Cellular Imaging. Chemistry - A European Journal, 14(19), 5812-5819. doi:10.1002/chem.200800309Han, J., Loudet, A., Barhoumi, R., Burghardt, R. C., & Burgess, K. (2009). A Ratiometric pH Reporter For Imaging Protein-dye Conjugates In Living Cells. Journal of the American Chemical Society, 131(5), 1642-1643. doi:10.1021/ja8073374Kolemen, S., Işık, M., Kim, G. M., Kim, D., Geng, H., Buyuktemiz, M., … Akkaya, E. U. (2015). Intracellular Modulation of Excited-State Dynamics in a Chromophore Dyad: Differential Enhancement of Photocytotoxicity Targeting Cancer Cells. Angewandte Chemie, 127(18), 5430-5434. doi:10.1002/ange.201411962Bachollet, S. P. J. T., Volz, D., Fiser, B., Münch, S., Rönicke, F., Carrillo, J., … Harrity, J. P. A. (2016). A Modular Class of Fluorescent Difluoroboranes: Synthesis, Structure, Optical Properties, Theoretical Calculations and Applications for Biological Imaging. Chemistry - A European Journal, 22(35), 12430-12438. doi:10.1002/chem.201601915Frath, D., Didier, P., Mély, Y., Massue, J., & Ulrich, G. (2017). Vectorization and Intracellular Distribution of a Two-Photon-Absorbing, Near-Infrared-Emitting π-Extended Boranil Dye. ChemPhotoChem, 1(4), 109-112. doi:10.1002/cptc.201700012Melaimi, M., & Gabbaï, F. P. (2005). A Heteronuclear Bidentate Lewis Acid as a Phosphorescent Fluoride Sensor. Journal of the American Chemical Society, 127(27), 9680-9681. doi:10.1021/ja053058sHudnall, T. W., Kim, Y.-M., Bebbington, M. W. P., Bourissou, D., & Gabbaï, F. P. (2008). Fluoride Ion Chelation By a Bidentate Phosphonium/Borane Lewis Acid. Journal of the American Chemical Society, 130(33), 10890-10891. doi:10.1021/ja804492yWade, C. R., Broomsgrove, A. E. J., Aldridge, S., & Gabbaï, F. P. (2010). 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The Journal of Organic Chemistry, 80(8), 4097-4107. doi:10.1021/acs.joc.5b00416Pais, V. F., Lineros, M., López-Rodríguez, R., El-Sheshtawy, H. S., Fernández, R., Lassaletta, J. M., … Pischel, U. (2013). Preparation and pH-Switching of Fluorescent Borylated Arylisoquinolines for Multilevel Molecular Logic. The Journal of Organic Chemistry, 78(16), 7949-7961. doi:10.1021/jo401147tPais, V. F., Lassaletta, J. M., Fernández, R., El-Sheshtawy, H. S., Ros, A., & Pischel, U. (2014). Organic Fluorescent Thermometers Based on Borylated Arylisoquinoline Dyes. Chemistry - A European Journal, 20(25), 7638-7645. doi:10.1002/chem.201402027Domínguez, Z., López-Rodríguez, R., Álvarez, E., Abbate, S., Longhi, G., Pischel, U., & Ros, A. (2018). Azabora[5]helicene Charge-Transfer Dyes Show Efficient and Spectrally Variable Circularly Polarized Luminescence. Chemistry - A European Journal, 24(48), 12660-12668. doi:10.1002/chem.201801908Zhu, L., Shabbir, S. H., Gray, M., Lynch, V. 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QUANTUM EFFICIENCIES OF FLUORESCENCE OF ORGANIC SUBSTANCES: EFFECT OF SOLVENT AND CONCENTRATION OF THE FLUORESCENT SOLUTE1. The Journal of Physical Chemistry, 65(2), 229-235. doi:10.1021/j100820a00

BASHY Dye Platform Enables the Fluorescence Bioimaging of Myelin Debris Phagocytosis by Microglia during Demyelination

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that is characterized by the presence of demyelinated regions with accumulated myelin lipid debris. Importantly, to allow effective remyelination, such debris must be cleared by microglia. Therefore, the study of microglial activity with sensitive tools is of great interest to better monitor the MS clinical course. Using a boronic acid-based (BASHY) fluorophore, specific for nonpolar lipid aggregates, we aimed to address BASHY’s ability to label nonpolar myelin debris and image myelin clearance in the context of demyelination. Demyelinated ex vivo organotypic cultures (OCSCs) and primary microglia cells were immunostained to evaluate BASHY’s co-localization with myelin debris and also to evaluate BASHY’s specificity for phagocytosing cells. Additionally, mice induced with experimental autoimmune encephalomyelitis (EAE) were injected with BASHY and posteriorly analyzed to evaluate BASHY+ microglia within demyelinated lesions. Indeed, in our in vitro and ex vivo studies, we showed a significant increase in BASHY labeling in demyelinated OCSCs, mostly co-localized with Iba1-expressing amoeboid/phagocytic microglia. Most importantly, BASHY’s presence was also found within demyelinated areas of EAE mice, essentially co-localizing with lesion-associated Iba1+ cells, evidencing BASHY’s potential for the in vivo bioimaging of myelin clearance and myelin-carrying microglia in regions of active demyelination.This work was supported by Grant for Multiple Sclerosis Innovation-Merck Serono to AF, Young Investigator’s Projects for Collaborative Cross-disciplinary Studies from iMed.ULisboa to A.F. and F.S.; PTDC/QUI-QOR/29967/2017 and LISBOA-01-0145-FEDER-029967 to P.G.; the Spanish Ministry of Science, Innovation, and Universities (CTQ2017-89832-P for U.P.); the PhD grant 2021.04911.BD from Fundação para a Ciência e Tecnologia, Portugal (FCT) to M.V.P.; and in part by UIDB/04138/2020 and UIDP/04138/2020-from FCT to iMed.ULisboa

Red-Emitting Tetracoordinate Organoboron Chelates: Synthesis, Photophysical Properties, and Fluorescence Microscopy

Seven tetracoordinate organoboron fluorophores with heterobiaryl N,O- or N,N-chelate ligands were prepared and photophysically characterized (in toluene). The electronic variation of the heteroaromatic moiety provided a means for the fine-tuning of the UV/vis absorption and emission spectra. In the most interesting cases, the spectra were red-shifted to maximum absorbance at wavelengths longer than 500 nm and emission maxima between 620 and 660 nm. The pronounced intramolecular charge-transfer character of the dyes yielded large Stokes shifts (3500-5100 cm), while maintaining appreciable fluorescence quantum yields of up to 0.2 for emission maxima longer than 600 nm. The lipophilic character of the dyes enabled their application as stains of vesicle substructures in confocal fluorescence microscopy imaging.Ministerio de Economía y Competitividad CTQ2014-54729 - C2 - 1 - P for U.P., CTQ2013 - 48164 - C2 - 1 - P , CTQ2013 - 48164 - C2 - 2 - P for A.R., CTQ2013 - 41339 - P, CTQ2015 - 71896 - REDT for E.P.I., Ramón y Cajal contract RYC - 2013 - 12585 for A.R.FEDER FundJunta de Andalucía 2012/FQM - 2140 for U.P., 2009/FQM - 4537 and 2012/FQM - 1078 for A.R

Photomodulation of ultrastable host–guest complexes in water and their application in light-controlled steroid release

The cucurbit[8]uril (CB8) synthetic receptor is shown to form high-affinity host-guest complexes with dicationic dithienylethene (DTE) photoswitches in water. ITC experiments combined with computational studies suggest that the formation of the inclusion complexes is mainly driven by a combination of hydrophobic effects, ion-dipole, hydrogen- and chalcogen-bonding interactions. The binding affinities were observed to be much higher for the DTE closed isomers, reaching values in the picomolar range (up to 1011 M−1) while the open isomers display up to 10 000-fold lower affinities, setting ideal conditions for the development of robust photoswitchable host-guest complexes. The light-responsive affinity of these photoswitches toward CB8 was explored to control the encapsulation and release of nanomolar affinity steroids via competitive guest replacement.publishersversionpublishe

Toward Two-Photon Absorbing Dyes with Unusually Potentiated Nonlinear Fluorescence Response

The combination of two two-photon-induced processes in a F\uf6rster resonance energy transfer (FRET)-operated photochromic fluorene-dithienylethene dyad lays the foundation for the observation of a quartic dependence of the fluorescence signal on the excitation light intensity. While this photophysical behavior is predicted for a four-photon absorbing dye, the herein proposed approach opens the way to use two-photon absorbing dyes, reaching the same performance. Hence, the spatial resolution limit, being a critical parameter for applications in fluorescence imaging or data storage with common two-photon absorbing dyes, is dramatically improved

Toward Light-Controlled Supramolecular Peptide Dimerization

The selective photodeprotection of the NVoc-modified FGG tripeptide yields the transformation of its 1:1 receptor−ligand complex with cucurbit[8]uril into a homoternary FGG2@CB8 assembly. The resulting lightinduced dimerization of the model peptide provides a tool for the implementation of stimuli-responsive supramolecular chemistry in biologically relevant contexts.The work was supported by the Associate Laboratory for Green ChemistryLAQV (UIDB/50006/2020) and by the Applied Molecular Biosciences UnitUCIBIO (UIDB/ 04378/2020), both financed by FCT. FCT/MCTES is also acknowledged for supporting the National Portuguese NMR Network (ROTEIRO/0031/2013-PINFRA/22161/2016, cofinanced by FEDER through COMPETE 2020, POCI, PORL, and FCT through PIDDAC) and for the grants PTDC/QUICOL/32351/2017, PTDC/QUI-QFI/30951/2017, and CEECIND/00466/2017 (N.B.). U.P. thanks the Spanish Ministry of Science, Innovation, and Universities (CTQ2017-89832-P). We are grateful to Dr. J.P. Da Silva for the mass spectrometry data (equipment financed by CRESC Algarve 2020 and COMPETE 2020; project EMBRC.PT ALG-01-0145-FEDER022121). Funding for open access charge: Universidad de Huelva / CBU