Strongly Emissive and Photostable Four‐Coordinate Organoboron N,C Chelates and Their Use in Fluorescence Microscopy |
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| Authors: | Dr. Vânia F. Pais María M. Alcaide Rocío López‐Rodríguez Dr. Daniel Collado Dr. Francisco Nájera Prof. Ezequiel Pérez‐Inestrosa Dr. Eleuterio Álvarez Prof. José M. Lassaletta Prof. Rosario Fernández Dr. Abel Ros Dr. Uwe Pischel |
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| Affiliation: | 1. CIQSO ‐ Center for Research in Sustainable Chemistry and Department of Chemical Engineering, Physical Chemistry and Organic Chemistry, University of Huelva, Campus de El Carmen, s/n, 21071 Huelva (Spain);2. Institute for Chemical Research (CSIC‐US) and Innovation‐Center in Advanced Chemistry (ORFEO‐CINQA), C/Américo Vespucio 49, 41092 Seville (Spain);3. Department of Organic Chemistry, University of Seville and Innovation‐Center in Advanced Chemistry (ORFEO‐CINQA), C/Prof. García González 1, 41012 Seville (Spain);4. Department of Organic Chemistry, University of Málaga, IBIMA, Campus Teatinos, s/n, 29071 Málaga (Spain) and Andalusian Center for Nanomedicine and Biotechnology ‐ BIONAND, Parque Tecnológico de Andalucía, 29590 Málaga (Spain) |
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| Abstract: | Six strongly fluorescent four‐coordinate organoboron N,C chelates containing an aryl isoquinoline skeleton were prepared. Remarkably, the fluorescence quantum yields reach values of up to 0.74 in oxygen‐free toluene. The strong B?N interaction was corroborated by the single‐crystal X‐ray analysis of two dyes. The intramolecular charge‐transfer character of the fluorophores was evidenced by solvatochromism studies and time‐dependent DFT calculations at the PCM(toluene)/CAM‐B3LYP/6‐311++G(2d,p)//PCM(toluene)/B3LYP/6‐311G(2d,p) level of theory. The compounds combine high chemical stability with high photostability, especially when equipped with electron‐donating substituents. The strong fluorescence and the large Stokes shifts predestine these compounds for use in confocal fluorescence microscopy. This was demonstrated for the imaging of the N13 mouse microglial cell line. Moreover, significant two‐photon absorption cross sections (up to 61 GM) allow the use of excitation wavelengths in the near‐infrared region (>800 nm). |
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| Keywords: | boron charge transfer chelates dyes/pigments fluorescence |
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