Syntheses, Structure, and Optical Properties of Ladder-Type Fused Azaborines

Agou, Tomohiro; Kobayashi, Junji; Kawashima, Takayuki

doi:10.1021/ol060539n

Cited by 141 publications

(85 citation statements)

References 19 publications

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“…Other methods include Wacker type cyclisations, hydroboration with NHC borenium ions, and construction of the targeted PAH framework around a pre‐installed boron center via Yamamoto coupling or Scholl reactions . Pioneering work by Kawashima et al on the synthesis of 1,4‐B,N‐doped linear acenes for applications in OLEDs established the growing class of 1,4‐azaborines . Embedding 1,4‐azaborine units into the scaffold of benzo[4]helicene (DABNA and v DABNA in Scheme ) by Hatakeyama et al.…”

Section: Methodsmentioning

confidence: 99%

Intramolecular Borylation via Sequential B−Mes Bond Cleavage for the Divergent Synthesis of B,N,B‐Doped Benzo[4]helicenes

et al. 2020

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New symmetric and unsymmetric B,N,B‐doped benzo[4]helicenes 3–6 a/b have been achieved in good yields, using a three‐step process, starting from N(tolyl)3 in a highly divergent manner (7 examples). A borinic acid functionalized 1,4‐B,N‐anthracene 1 was found to display unprecedented reactivity, acting as a convenient and highly effective precursor for selective formation of bromo‐substituted B,N,B‐benzo[4]helicenes 2 a/2 b via intramolecular borylation and sequential B−Mes bond cleavage in the presence of BBr3. Subsequent reaction of 2 a/2 b with Ar‐Li provided a highly effective toolbox for the preparation of symmetrically/unsymmetrically functionalized B,N,B‐helicenes. Their high photoluminescence quantum yields along with the small ΔEST suggest their potential as thermally activated delayed fluorescence (TADF) emitters for organic light‐emitting diodes (OLEDs).

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Section: Methodsmentioning

confidence: 99%

Intramolecular Borylation via Sequential B−Mes Bond Cleavage for the Divergent Synthesis of B,N,B‐Doped Benzo[4]helicenes

et al. 2020

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“…Synthesis of ladder‐type heteraborins : The synthesized ladder‐type molecules have two or three heteraborin units connected by phenylene linkages (Scheme ). The syntheses of pentacene‐type azaborines 1 and 3 as well as heptacene‐type azaborine 5 have been already reported 17…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we reported the electronic and optical properties of new hetero‐π‐conjugated molecules based on dibenzoheteraborin units 16. In the previous communication, we reported the synthesis and preliminary study on optical properties of ladder‐type azaborines 17. UV‐visible spectra of these molecules showed red shift of absorption maxima in accordance with extension of the π systems, indicating enhancement of π conjugation through the ladder‐type molecular framework.…”

Section: Introductionmentioning

confidence: 88%

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Electronic and Optical Properties of Ladder‐Type Heteraborins

Agou

Kobayashi

Kawashima

2007

Chemistry A European J

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Ladder-type pi-conjugated molecules bearing heteraborin (azaborine or thiaborin) units were synthesized, and X-ray crystallographic analysis of pentacene-type molecules showed that these molecules have rigid and planar structures. UV-visible spectroscopy and theoretical calculations revealed the enhancement of electronic interaction between heteraborin units, the decrease in HOMO-LUMO energy gaps, and the strong effect of the bridging main-group elements (nitrogen or sulfur) on the electronic states. The ladder-type molecules emitted strong fluorescence both in solution and in the solid state, and the emission-band shapes were different from each other, indicating the existence of intermolecular interactions in the solid state. Complex formation of the ladder molecules with fluoride ion was monitored by UV-visible spectroscopy, which revealed that the Lewis acidity of these molecules can be controlled by the elongation of pi systems and the change of the bridging main-group elements.

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“…[86] The synthesis of BN-pentacene 128 was achieved by treatment of the para-diamino arene 127 with MesB(OMe) 2 (Scheme 37). Similar transformations from meta-diamino arene 129 and triaminoarene 131 generated 130 and 132 , respectively.…”

Section: The Kawashima Group – University Of Tokyomentioning

confidence: 99%

Recent Advances in Azaborine Chemistry

2012

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The chemistry of organoboron compounds has been primarily dominated by their use as powerful reagents in synthetic organic chemistry. Recently, the incorporation of boron as part of a functional target structure has emerged as a useful way to generate diversity in organic compounds. A commonly applied strategy is the replacement of a CC unit with its isoelectronic BN unit. In particular, the BN/CC isosterism of the ubiquitous arene motif has undergone a renaissance in the past decade. The parent molecule of the 1,2-dihydro-1,2-azaborine family has now been isolated. New mono- and polycyclic BN heterocycles have been synthesized for potential use in biomedical and materials science applications. This review is a tribute to Dewar's first synthesis of a monocyclic 1,2-dihydro-1,2-azaborine 50 years ago and discusses recent advances in the synthesis and characterization of carbon(C)-boron(B)-nitrogen(N)-containing heterocycles.

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Syntheses, Structure, and Optical Properties of Ladder-Type Fused Azaborines

Cited by 141 publications

References 19 publications

Intramolecular Borylation via Sequential B−Mes Bond Cleavage for the Divergent Synthesis of B,N,B‐Doped Benzo[4]helicenes

Intramolecular Borylation via Sequential B−Mes Bond Cleavage for the Divergent Synthesis of B,N,B‐Doped Benzo[4]helicenes

Electronic and Optical Properties of Ladder‐Type Heteraborins

Recent Advances in Azaborine Chemistry

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