Endowing a triarylboron compound showing ACQ with AIE characteristics by transforming its emissive TICT state to be dark

Fluorescence spectroscopy as an analytical tool for various applications as well as fluorescence probes showing a sensitive behavior towards their microenvironmental properties have experienced an increasing interest in research in the last decades. Recently our group has contributed to this field of interest by introducing a novel mechanism where a planarization in the excited state occurs leading to an advantageous allowed emission. Here, we provide an overview of intramolecular charge transfer states where a rotation in the excited state causes a high sensitivity for microenvironmental changes. Furthermore, effects which influence the surroundings of the fluorophores are described in detail. Recent results where twisted intramolecular charge transfer (TICT) and aggregation‐induced emission (AIE) effects were combined are described and a promising outlook for further research progress is provided.

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Section: Biological Applicationsmentioning

confidence: 99%

“…[61] Although the nanogel only distributes in the cytoplasm [62] the nucleus also showed a bright fluorescence. By confocal fluorescence microscopy it was found that small aggregates show a strong fluorescence emission in the cytoplasm.…”

Section: Biological Applicationsmentioning

confidence: 99%

Rotations in Excited ICT States – Fluorescence and its Microenvironmental Sensitivity

Liese

Haberhauer

2018

Israel Journal of Chemistry

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“…Within the past few years, several chromophores containing triarylboryl moieties have been shown to be applicable in biological imaging [49–65] . Since their first report in the literature 135 years ago, [66, 67] triarylboranes have found applications in many different fields, such as metal–organic framework (MOF) chemistry, anion sensing and optoelectronics [68–70] .…”

Section: Introductionmentioning

confidence: 99%

Bis(phenylethynyl)arene Linkers in Tetracationic Bis‐triarylborane Chromophores Control Fluorimetric and Raman Sensing of Various DNAs and RNAs

Ferger

Ban

Krošl

et al. 2021

Chemistry A European J

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We report four new luminescent tetracationic bis‐triarylborane DNA and RNA sensors that show high binding affinities, in several cases even in the nanomolar range. Three of the compounds contain substituted, highly emissive and structurally flexible bis(2,6‐dimethylphenyl‐4‐ethynyl)arene linkers (3: arene=5,5′‐2,2′‐bithiophene; 4: arene=1,4‐benzene; 5: arene=9,10‐anthracene) between the two boryl moieties and serve as efficient dual Raman and fluorescence chromophores. The shorter analogue 6 employs 9,10‐anthracene as the linker and demonstrates the importance of an adequate linker length with a certain level of flexibility by exhibiting generally lower binding affinities than 3–5. Pronounced aggregation–deaggregation processes are observed in fluorimetric titration experiments with DNA for compounds 3 and 5. Molecular modelling of complexes of 5 with AT‐DNA, suggest the minor groove as the dominant binding site for monomeric 5, but demonstrate that dimers of 5 can also be accommodated. Strong SERS responses for 3–5 versus a very weak response for 6, particularly the strong signals from anthracene itself observed for 5 but not for 6, demonstrate the importance of triple bonds for strong Raman activity in molecules of this compound class. The energy of the characteristic stretching vibration of the C≡C bonds is significantly dependent on the aromatic moiety between the triple bonds. The insertion of aromatic moieties between two C≡C bonds thus offers an alternative design for dual Raman and fluorescence chromophores, applicable in multiplex biological Raman imaging.

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“…A large number of air-stable conjugated three-coordinate organoboron compounds have been synthesized over the last few decades [1][2][3][4][5][6][7][8] for various applications, particularly in linear [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] and nonlinear [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] optics, electro-optic devices, [40][41][42] anion sensors, [43,44] cell imaging, [45][46][47][48] etc. The boron center in these species possesses an empty p-orbital and can thus serve as a strong π-acceptor following photo-excitation, or as a readily reducible center.…”

Section: Introductionmentioning

confidence: 99%

Insights into the Optical Properties of Triarylboranes with Strongly Electron‐Accepting Bis(fluoromesityl)boryl Groups: when Theory Meets Experiment

et al. 2019

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The photophysical properties (absorption, fluorescence and phosphorescence) of a series of triarylboranes of the form 4‐D−C6H4−B(Ar)2 (D=tBu or NPh2; Ar=mesityl (Mes) or 2,4,6‐tris(trifluoromethylphenyl (Fmes)) were analyzed theoretically using state‐of‐the‐art DFT and TD‐DFT methods. Simulated emission spectra and computed decay rate constants are in very good agreement with the experimental data. Unrestricted electronic computations including vibronic contributions explain the unusual optical behavior of 4‐tBu−C6H4−B(Fmes)2 2, which shows both fluorescence and phosphorescence at nearly identical energies (at 77 K in a frozen glass). Analysis of the main normal modes responsible for the phosphorescence vibrational fine structure indicates that the bulky tert‐butyl group tethered to the phenyl ring is strongly involved. Interestingly, in THF solvent, the computed energies of the singlet and triplet excited states are very similar for compound 2 only, which may explain why 2 shows phosphorescence in contrast to the other members of the series.

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Endowing a triarylboron compound showing ACQ with AIE characteristics by transforming its emissive TICT state to be dark

Abstract: A triarylboron-based AIE fluorophore, TAB-AIE-FL, was designed and synthesized by introducing an electron acceptor to boost charge separation, transforming its TICT state from bright emission to dark.

Cited by 22 publications

References 27 publications

Rotations in Excited ICT States – Fluorescence and its Microenvironmental Sensitivity

Rotations in Excited ICT States – Fluorescence and its Microenvironmental Sensitivity

Bis(phenylethynyl)arene Linkers in Tetracationic Bis‐triarylborane Chromophores Control Fluorimetric and Raman Sensing of Various DNAs and RNAs

Insights into the Optical Properties of Triarylboranes with Strongly Electron‐Accepting Bis(fluoromesityl)boryl Groups: when Theory Meets Experiment

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