Comparison of luminescent properties of helicene-like bibenzothiophenes with o-carborane and 5,6-dicarba-nido-decaborane

Nishino, Kunihiko; Hashimoto, Kazushi; Tanaka, Kazuo; Morisaki, Yasuhiro; Chujo, Yoshiki

doi:10.1007/s11426-018-9258-y

“…On the basis of these results, we regard o ‐carborane as a conjugated “element‐block”,, which is the minimum functional unit consist of heteroatoms, and designed various aryl‐modified molecules to obtain optical materials . So far, the series of unique luminescent materials have been prepared by the combination of various aromatic rings, such as aggregation‐induced emission,, intense solid‐state luminescence with almost quantitative efficiencies in the visible region,, a highly‐stable near‐infrared luminophore and stimuli‐responsive luminochromic behaviors . Except for these materials, wide variety of solid‐state luminescent o ‐carboranes have been recently discovered.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Solid‐State Excimer Emission of the Aryl–Ethynyl‐o‐Carborane Skeleton by Acridine Introduction

Ochi

¹

,

Tanaka

²

,

Chujo

³

2019

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We report highly‐efficient and solid‐state excimer emission based on the acridine–o‐carborane dyad possessing the ethynyl spacer. The previous pyrene‐modified o‐carborane showed excimer emission only at 77 K in the crystalline state, meanwhile, the current acridine‐modified molecule presented excimer emission with high efficiency (ΦPL = 0.23) in the crystalline state at room temperature. From single‐crystal X‐ray crystallography, it was indicated that two acridine moieties were stacked and the third acridine molecule was out of alignment. Such a packing mode could restrict exciton splitting over the columnar packing structure. Moreover, molecular interactions through the nitrogen atom in the acridine moiety and the hydrogen atom in the o‐carborane unit contribute to suppression of molecular motions. As a consequence, an improved emission efficiency was obtained. This study demonstrates that the ethynyl–o‐carborane skeleton should work as the excimer‐inducible component in the solid state.

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“…In contrast, when another boron atom is removed, the neutral compound, which is also called a nido ‐carborane, is produced. From this compound, electron‐accepting ability is obtained, and solid‐state luminescence with stimuli‐responsivity was induced . Helicene‐connected o ‐ and nido ‐carboranes lacking two boron atoms were simultaneously generated in a single reaction, and mechanochromic luminescence was detected only from the nido ‐carborane (Figure ).…”

Section: Mechanochromic Luminescencementioning

confidence: 99%

Recent Progress in the Development of Solid‐State Luminescent o‐Carboranes with Stimuli Responsivity

Ochi

¹

,

Tanaka

²

,

Chujo

³

2020

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o‐Carborane, a cluster compound containing boron and adjacent carbon atoms, displays intriguing luminescent properties. Recently, compounds containing o‐carborane units were found to show suppressed aggregation‐induced quenching and intense solid‐state emission; they also show potential for the development of stimuli‐responsive luminochromic materials. In this Minireview, we introduce three kinds of fundamental photochemical properties: aggregation‐induced emission, twisted intramolecular charge transfer in crystals, and environment‐sensitive excimer formation in solids. Based on these properties, several types of luminochromism, such as thermos‐, vapo‐, and mechanochromism, have been discovered. Based mainly on results from recent studies, we illustrate these mechanisms as well as unique luminescent behaviors of o‐carborane derivatives.

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“…It is proposed that electronic conjugation should be drastically changed by the formation of dative bond between fluoride and tricoordinate boron at the substituent. The modified o-carboranes having stimuli-responsive luminochromism in solid have been reported (76)(77)(78)(79)(80)(81)(82)(83)(84)(85)). [61][62][63][64][65][66][67][68] The details are explained later.…”

Section: -1 O-carborane Derivatives With Aie Propertiesmentioning

confidence: 99%

Recent Progress in the Development of Solid‐State Luminescent o‐Carboranes with Stimuli Responsivity

Ochi

¹

,

Tanaka

²

,

Chujo

³

2020

Self Cite

View full text Add to dashboard Cite

o‐Carborane, a cluster compound containing boron and adjacent carbon atoms, displays intriguing luminescent properties. Recently, compounds containing o‐carborane units were found to show suppressed aggregation‐induced quenching and intense solid‐state emission; they also show potential for the development of stimuli‐responsive luminochromic materials. In this Minireview, we introduce three kinds of fundamental photochemical properties: aggregation‐induced emission, twisted intramolecular charge transfer in crystals, and environment‐sensitive excimer formation in solids. Based on these properties, several types of luminochromism, such as thermos‐, vapo‐, and mechanochromism, have been discovered. Based mainly on results from recent studies, we illustrate these mechanisms as well as unique luminescent behaviors of o‐carborane derivatives.

show abstract

Comparison of luminescent properties of helicene-like bibenzothiophenes with o-carborane and 5,6-dicarba-nido-decaborane

Cited by 21 publications

References 41 publications

Improvement of Solid‐State Excimer Emission of the Aryl–Ethynyl‐o‐Carborane Skeleton by Acridine Introduction

Improvement of Solid‐State Excimer Emission of the Aryl–Ethynyl‐o‐Carborane Skeleton by Acridine Introduction

Recent Progress in the Development of Solid‐State Luminescent o‐Carboranes with Stimuli Responsivity

Recent Progress in the Development of Solid‐State Luminescent o‐Carboranes with Stimuli Responsivity

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