Photodissociation of B–N Lewis Adducts: A Partially Fused Trinaphthylborane with Dual Fluorescence

Matsuo, Kyohei; Saito, Shohei; Yamaguchi, Shigehiro

doi:10.1021/ja506980p

Cited by 167 publications

(118 citation statements)

References 36 publications

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“…In addition, we monitored the excitation spectra for the above two emission peaks ( λ em at 433 and 556 nm, respectively) of HAC : 2 BF 3 adduct. During this titration, a broad excitation band peaking around 486 nm was observed in the case of λ em =556 nm (Figure S46), whereas no observable change in the excitation spectra of λ em =433 nm was seen (Figure S45) . The adduct formation could be easily reversed by exposure to a Lewis base such as ammonia to regenerate the original color/UV/Vis profile of HAC (Figure S34).…”

Section: Figurementioning

confidence: 99%

Heli(aza)cene: A Helical Molecular Tweezer with Tunable Intra‐ and Intermolecular Charge Transfer

Kumar

Semwal

Choudhury

et al. 2017

Chemistry A European J

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Non-planar fluorophores offer unique avenues of intra- and intermolecular energy transfer not available in their planar counterparts. We have rationally designed a molecular tweezer based on the pyridine-2,6-dicarboxamide framework having two structurally similar arms with extended π-surface. We termed this molecular tweezer as Heli(aza)cene (HAC) due to its spontaneous adoption of helical conformation stabilized by the amide and imine moieties present in it. In the helical conformation, the two arms of HAC are twisted unequally. This asymmetry confers dissimilar electronic character to the two arms and results in intramolecular charge transfer interactions in HAC. Homochiral stacking of the P- and the M- helices in crystal, and profound redshifting of the emission at higher concentrations of HAC was attributed to intermolecular charge-transfer interactions in aggregated/crystal state. Exposure of HAC, in solution as well as in the solid state, to Lewis/Brønsted acids results in rapid and vibrant color changes. This is the first example of a π-layered helical molecule exhibiting tunable intra-/intermolecular charge-transfer characteristics.

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Section: Figurementioning

confidence: 99%

Heli(aza)cene: A Helical Molecular Tweezer with Tunable Intra‐ and Intermolecular Charge Transfer

Kumar

Semwal

Choudhury

et al. 2017

Chemistry A European J

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“…The boron–nitrogen coordination bond (B←N) is one typical kind of Lewis acid/base pair . The intermolecular B←N Lewis pair has been employed to modulate molecular orbitals and thereby to tune absorption and fluorescence spectra of conjugated molecules and polymers . Our group has recently discovered that intramolecular B←N Lewis pair formation can significantly downshift LUMO/HOMO energy levels ( E LUMO / E HOMO ) of conjugated polymers .…”

Section: Introductionmentioning

confidence: 99%

Effects of the Substituents of Boron Atoms on Conjugated Polymers Containing B←N Units

Wang

Dou

et al. 2018

Chemistry A European J

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Organoboron chemistry is a new tool to tune the electronic structures and properties of conjugated polymers, which are important for applications in organic optoelectronic devices. To investigate the effects of substituents of boron atoms on conjugated polymers, we synthesized three conjugated polymers based on double B←N-bridged bipyridine (BNBP) with various substituents on the boron atoms. By changing the substituents from four phenyl groups and two phenyl groups/two fluorine atoms to four fluorine atoms, the BNBP-based polymers show blue-shifted absorption spectra, decreased LUMO/HOMO energy levels, and enhanced electron affinities, as well as increased electron mobilities. Moreover, these BNBP-based polymers can be used as electron acceptors for all-polymer solar cells. These results demonstrate that substituents of boron atoms can effectively modulate the electronic properties and applications of conjugated polymers.

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“…Although most conventional organic luminescent dyes show weak emission in the solid state due to aggregation‐caused quenching (ACQ), several strategies for overcoming this problem have been established. For example, brightly luminescent materials have been invented on the basis of the strategy for introducing bulky groups into organoboron compounds and boron complexes, which can show emission in solution . Since the first report on aggregation‐induced emission (AIE) was published, AIE‐active molecules have attracted attention not only for preparing bright solid‐state luminescent materials but also for developing stimuli‐responsive materials .…”

Section: Introductionmentioning

confidence: 99%

“…For example, brightly luminescent materials have been invented on the basis of the strategy for introducing bulky groups into organoboron compounds and boron complexes, which can show emission in solution. [1][2][3][4][5][6][7][8][9][10] Since the first report on aggregation-induced emission (AIE) was published, [11] AIE-active molecules have attracted attention not only for preparing bright solid-state luminescent materials [12][13][14][15] but also for developing stimuli-responsive materials. [16][17][18] Indeed, so far, a large number of new AIE-active molecules have been applied as bioprobes and environmental sensors.…”

Section: Introductionmentioning

confidence: 99%

Design and Luminescence Chromism of Fused Boron Complexes Having Constant Emission Efficiencies in Solution and in the Amorphous and Crystalline States

2017

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Mechanochromic luminescent molecules often suffer from critical loss of luminescence intensity during phase transitions in the solid state. In this study, we present mechanochromic luminescent molecules that can provide clear color changes with constant emission intensity during phase transitions. It was reported that the class of aggregation‐induced emission (AIE)‐active boron complexes can present intense emission by freezing intramolecular motions. According to this mechanism, we designed a complex with a fused ligand to preserve the enhanced emission in the aggregated state in the AIE during phase transitions between the solution, amorphous, and crystalline states. From optical measurements, it was shown that the synthesized boron complexes present bright emission in various phases. In particular, as we expected, the luminescence color was clearly altered during phase transition, whereas the emission intensity changed only slightly. Finally, we also found that diverse luminescence colors were obtained from each polymorph and for various substituents as induced by the substituent effect. The results in the series of mechanistic studies show that electronic interactions and π–π interactions can modulate the electronic conjugation system of the complexes without causing loss of emission efficiency.

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Photodissociation of B–N Lewis Adducts: A Partially Fused Trinaphthylborane with Dual Fluorescence

Cited by 167 publications

References 36 publications

Heli(aza)cene: A Helical Molecular Tweezer with Tunable Intra‐ and Intermolecular Charge Transfer

Heli(aza)cene: A Helical Molecular Tweezer with Tunable Intra‐ and Intermolecular Charge Transfer

Effects of the Substituents of Boron Atoms on Conjugated Polymers Containing B←N Units

Design and Luminescence Chromism of Fused Boron Complexes Having Constant Emission Efficiencies in Solution and in the Amorphous and Crystalline States

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