The butterfly effect in bisfluorenylidene-based dihydroacenes: aggregation induced emission and spin switching

Yin, Xiaodong; Low, Jonathan Z.; Fallon, Kealan J.; Paley, Daniel W.; Campos, Luis M.

doi:10.1039/c9sc04096j

Cited by 51 publications

(49 citation statements)

References 51 publications

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“…The coordination sphere of the boron atoms is close to trigonalplanar (4a S B1-4 each 359.48 8; 4b S B = 359.3, 359.78 8); however, they are significantly bent out of the central B 2 C 4 ring plane by 44.0-45.38 8.S uch bent, butterfly-type structures were also reported for related isoelectronic,quinoidal anthracenes with carbon-based substituents in 9,10-positions. [27] Thes trong electronic impact of the cAAC R ligands becomes evident by inspection of the exocyclic BÀC cAAC bonds of 4a/4b (1.506-(7)-1.531(2) ). These are notably shortened as compared to radical cations 3a/3b with typical dative single bonds (1.632-(5), 1.638(5) ), which implies substantial delocalization of the two unpaired electrons in 4a/4b and BÀC cAAC multiple bond character.…”

Section: Resultsmentioning

confidence: 99%

cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States

et al. 2020

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NarrowH OMO-LUMO gaps and high chargecarrier mobilities make larger acenes potentially high-efficient materials for organic electronic applications.The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings.B ulk quantities, however,c an only be obtained reliably for acenes up to heptacene.T heoretically,(oligo)acenes and (poly)acenes are predicted to have open-shell singlet biradical and polyradical ground states,respectively,for which experimental evidence is still scarce.W eh ave nowb een able to dramatically lower the HOMO-LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated p system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)-(amino)carbenes gives neutral 9,10-diboraanthracenes,w hich are shown to feature disjointed, open-shell singlet biradical ground states.

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Section: Resultsmentioning

confidence: 99%

cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States

et al. 2020

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“…[171] Previously, it had been assumed that such motions as twisting, stretching, torsion, wagging, and rocking of AIEgens in solution causing nonradiative decay would effectively be shut off or dramatically attenuated in the solid state. [172][173][174][175][176] However, there is of course some motion and disorder that is always expected for any material above 0 K (the third law of thermodynamics). The significance of the remaining vibrational motions of TPE in the solid state was proven by the increase of PL of crystalline TPE analogs with decreasing temperature by temperature-dependent fluorescence measurements.…”

Section: Dynamic Aggregatesmentioning

confidence: 99%

Aggregate Science: From Structures to Properties

et al. 2020

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Molecular science entails the study of structures and properties of materials at the level of single molecules or small interacting complexes of molecules. Moving beyond single molecules and well‐defined complexes, aggregates (i.e., irregular clusters of many molecules) serve as a particularly useful form of materials that often display modified or wholly new properties compared to their molecular components. Some unique structures and phenomena such as polymorphic aggregates, aggregation‐induced symmetry breaking, and cluster excitons are only identified in aggregates, as a few examples of their exotic features. Here, by virtue of the flourishing research on aggregation‐induced emission, the concept of “aggregate science” is put forward to fill the gaps between molecules and aggregates. Structures and properties on the aggregate scale are also systematically summarized. The structure–property relationships established for aggregates are expected to contribute to new materials and technological development. Ultimately, aggregate science may become an interdisciplinary research field and serves as a general platform for academic research.

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“…[6,7] Diverse SLE luminogens with sterically congested structures, such as butterflylike or propeller-like shapes, have been designed to reduce intermolecular stacking interactions. [9,[22][23][24] In these cases,t he effect of intramolecular interactions on the photophysical properties of the material could gain importance and should also be considered. Styrylarenes are aw ell-known family of compounds, [25][26][27][28][29][30] but only af ew studies on their solid-state photophysical properties have been reported, to date.…”

Section: Introductionmentioning

confidence: 99%

Shedding Light on the Origin of Solid‐State Luminescence Enhancement in Butterfly Molecules

Sánchez-Ruíz

Rodríguez‐López

Garzón‐Ruiz

et al. 2020

Chemistry A European J

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Different molecular strategiesh ave been carefully evaluated to produce solid-statel uminescence enhancement (SLE) in compoundst hat show dark states in solution. As et of a-phenylstyrylarened erivatives with ab utterfly shape have been designeda nd synthesised, for the first time, with the aim of improving the solid-state fluorescencee mission of their parents tyrylarene compounds. Althought hese butterfly molecules are not fluorescenti ns olution, one of them (1,2,4,5-tetra(a-phenylstyryl)benzene)e xhibits af luorescence quantum yield as high as 68 %i nadrop-cast sample and 31 %i ni ts crystalline form. In contrast, 1,3,5-tris(a-phenylstyryl)benzene and 4,6-bis(a-phenylstyryl)pyrimidined on ot show SLE. Arange of fluorescencespectroscopy experiments and DFT calculations were carriedo ut to unravel the origin of different photophysical behaviour of these compounds in the solid state. The resultsindicatethat ar ational strategy to control the SLE effect in luminogens depends on ad elicate balance between molecularp roperties and inter-/intramolecular interactions in the solid state.

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The butterfly effect in bisfluorenylidene-based dihydroacenes: aggregation induced emission and spin switching

Abstract: Difluorenylidene dihydroanthracene with a butterfly-like structure exhibits both aggregation induced emission (AIE) and thermally activated ground-state spin switching properties.

Cited by 51 publications

References 51 publications

cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States

cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States

Aggregate Science: From Structures to Properties

Shedding Light on the Origin of Solid‐State Luminescence Enhancement in Butterfly Molecules

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