Dual emission <i>via</i> remote control of molecular rotation of <i>o</i>-carborane in the excited state by the distant substituents in tolane-modified dyads

Nishino, Kunihiko; Uemura, Kyoya; Tanaka, Kazuo; Chujo, Yoshiki

doi:10.1039/c7nj04283c

Cited by 27 publications

(22 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because of the steric structure of the o ‐carborane unit, non‐specific intermolecular interaction can be efficiently disturbed even in the condensed state, followed by highly‐efficient solid‐state luminescent properties. 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 .…”

Section: Introductionmentioning

confidence: 99%

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

2019

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

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

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Figure 5c and ds hows the time-resolvedf luorescence( TRF) profiles at two representative wavelengths;t he decay component of 450 nm emission and the corresponding rise of 630 nm emission are well resolved with as ingle time constant of approximately 20 ps, indicating that the reaction dynamics are rather homogeneous in terms of conformational disorder. These studies clearlys how that the peaks at 480 nm (weak) and 570 nm (strong) are assignable to an LE emission from silole and CT emission from (silole) d + (o-carborane) dÀ species, respectively.S imilar dual emission [27,46,47] and energy transfer [24,48] are commons pectroscopicf eatures for A Si-p-Cb (see Figure S7 in the Supporting Information). The results of these spectroscopic analyses indicate that the yellow emission of C Si-m-Cb occurs from the CT state, and that C Si-m-Cb has two separate excited states:t he LE and CT states,a nd grinding shuts off the yellow emission from the CT manifold so as to emit only blue emission, as shown in Figure 6.…”

Section: Steady-state Photophysical Propertiesmentioning

confidence: 96%

Solid‐State Photochromism by Molecular Assembly of Bis‐o‐carboranyl Siloles

Cho

Kim

Lee

et al. 2019

Chemistry A European J

View full text Add to dashboard Cite

A new type of solid‐state photochromism was observed in an AB2‐type molecular assembly comprising a central silole and two peripheral o‐carborane units, and in this assembly, depending on the assembling positions of those units at the adjoining benzene ring, two different regioisomers were formed: Si‐m‐Cb and Si‐p‐Cb. Each isomer showed different solid‐state photochromism depending on its solid‐state molecular conformation and was either in the crystalline or amorphous state. The crystals of each meta‐ or para‐isomer, CSi‐m‐Cb or CSi‐p‐Cb, showed yellow or blue emission, and mechanically grinding those crystals into amorphous powders of ASi‐m‐Cb and ASi‐p‐Cb, switched their emissions to blue and yellow, respectively. Photophysical studies revealed that the electronic interaction between silole and o‐carborane units determined the emission color. The crystal and DFT‐optimized structures each account for the crystalline and amorphous structures, respectively, and are correlated well with the electronic interactions in the molecular assembly in the solid state, thus enabling the prediction of the solid‐state molecular conformational change.

show abstract

“…To evaluate validity of this idea, the dyads were prepared and their optical properties were analyzed . All compounds showed solid‐state emission and 16 presents clear dual emission involving the LE and ICT emission bands . Interestingly, red emission from the ICT transition of 16 was observed from the crystal at 298 K, meanwhile blue emission from the LE transition was induced by cooling at 77 K. From the evaluation of energy barriers in the excited state with the Stevens–Ban plots, it was shown that the heights of energy barriers were significantly varied by the substituent effect.…”

Section: Twisted Intramolecular Charge Transfermentioning

confidence: 99%

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

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

Dual emission via remote control of molecular rotation of o-carborane in the excited state by the distant substituents in tolane-modified dyads

Abstract: Dual-emissive properties are reported based on the tolane-o-carborane dyads with various substituents.

Cited by 27 publications

References 52 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

Solid‐State Photochromism by Molecular Assembly of Bis‐o‐carboranyl Siloles

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

Contact Info

Product

Resources

About