Highly fluorescent columnar liquid crystals with elliptical molecular shape: oblique molecular stacking and excited-state intramolecular proton-transfer fluorescence

Seo, Jangwon; Kim, Sehoon; Gihm, Se Hoon; Park, Chong Rae; Park, Soo Young

doi:10.1039/b711883j

Cited by 71 publications

(33 citation statements)

References 45 publications

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“…This increase is, together with the redshift in UV/Vis, indicative of the formation of J-aggregates in dilute solutions in dodecane, a phenomenon also observed for discotics that contain oxadiazole moieties. [47] This formation of J-aggregates coincides with our molecular picture of a helical stack of discotic 2 in Figure 8. a) "Sergeant-and-soldiers" measurement with discotics 1 and 13; the g values were measured at 387 nm for mixtures of discotics 1 and 13 in heptane at RT.…”

Section: Full Papersupporting

confidence: 86%

Desymmetrization of 3,3′‐Bis(acylamino)‐2,2′‐bipyridine‐Based Discotics: The High Fidelity of Their Self‐Assembly Behavior in the Liquid‐Crystalline State and in Solution

Houtem

Martín‐Rapún

Vekemans

et al. 2010

Chemistry A European J

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Two novel nonsymmetrical disc-shaped molecules 1 and 2 based on 3,3'-bis(acylamino)-2,2'-bipyridine units were synthesized by means of a statistical approach. Discotic 1 possesses six chiral dihydrocitronellyl tails and one peripheral phenyl group, whereas discotic 2 possesses six linear dodecyloxy tails and one peripheral pyridyl group. Preorganization by strong intramolecular hydrogen bonding and subsequent aromatic interactions induce self-assembly of the discotics. Liquid crystallinity of 1 and 2 was determined with the aid of polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction. Two columnar rectangular mesophases (Col(r)) have been identified, whereas for C(3)-symmetrical derivatives only one Col(r) mesophase has been found. In solution, the molecularly dissolved state in chloroform was studied with (1)H NMR spectroscopy, whereas the self-assembled state in apolar solution was examined with optical spectroscopy. Remarkably, these desymmetrized discotics, which lack one aliphatic wedge, behave similar to the symmetric parent compound. To prove that the stacking behavior of discotics 1 and 2 is similar to that of reported C(3)-symmetrical derivatives, a mixing experiment of chiral 1 with C(3)-symmetrical 13 has been undertaken; it has shown that they indeed belong to one type of self-assembly. This helical J-type self-assembly was further confirmed with UV/Vis and photoluminescence (PL) spectroscopy. Eventually, disc 2, functionalized with a hydrogen-bonding acceptor moiety, might perform secondary interactions with molecules such as acids.

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Section: Full Papersupporting

confidence: 86%

Desymmetrization of 3,3′‐Bis(acylamino)‐2,2′‐bipyridine‐Based Discotics: The High Fidelity of Their Self‐Assembly Behavior in the Liquid‐Crystalline State and in Solution

Houtem

Martín‐Rapún

Vekemans

et al. 2010

Chemistry A European J

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“…In contrast, slightly enhanced k IC (E) in H-aggregates of DHIA compared to that in solution was observed to result in the decrease of Φ ESIPT by a factor of 0.7. Oxadiazole-based ESIPT molecules exhibiting high fl uorescence effi ciency in the crystalline [ 70 ] and liquid-crystalline (LC) state [ 71 ] were reported by Park group. SOX ( Figure 14 a) has only one hydroxyl group which can undergo ESIPT and showed strong bluish-green K * fl uorescence ( λ max = 486 nm) in the solid state ( Φ PL = 0.47) as well as in the solution ( Φ PL = 0.40).…”

Section: Aggregation-induced Enhanced Emission (Aiee)mentioning

confidence: 99%

“…An phasmidic derivative of DOX comprising a DOX core and two 3,4,5-tridodecyloxyphenyl substituents at the peripheral positions exhibited the monotropic LC behavior with enhanced emission (DOXG, Figure 14 c). [ 71 ] DOXG exhibited an apparent transition between two mesophases, the columnar hexagonal (Col h ) phase with a mosaic-like texture and columnar rectangular (Col r ) phase with a periodic pattern of lines. From the XRD pattern, it was found that the elliptical-shaped DOXG molecules are arranged in a tilted fashion within columns (Figure 14 d, e), namely, J-type stacking, resulting in the strong orange K * fl uorescence ( λ max = 573 nm, Φ PL = 0.34).…”

Section: Aggregation-induced Enhanced Emission (Aiee)mentioning

confidence: 99%

Advanced Organic Optoelectronic Materials: Harnessing Excited‐State Intramolecular Proton Transfer (ESIPT) Process

2011

Self Cite

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Recently, organic fluorescent molecules harnessing the excited-state intramolecular proton transfer (ESIPT) process are drawing great attention due to their unique photophysical properties which facilitate novel optoelectronic applications. After a brief introduction to the ESIPT process and related photo-physical properties, molecular design strategies towards tailored emission are discussed in relation to their theoretical aspects. Subsequently, recent studies on advanced ESIPT molecules and their optoelectronic applications are surveyed, particularly focusing on chemical sensors, fluorescence imaging, proton transfer lasers, and organic light-emitting diodes (OLEDs).

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“…Park and coworkers have synthesized excited-state intramolecular proton transfer-active molecule (73DOXG) which formed columnar liquid crystals with enhanced fluorescence emission [97]. The intramolecularly H-bonded core of 73DOXG produced columnar hexagonal and rectangular phases during cooling as a result of strong core-to-core interactions.…”

Section: Doxgbomentioning

confidence: 99%

Hydrogen Bonding for Supramolecular Liquid Crystals

Cheng

Gao

2015

Lecture Notes in Chemistry

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This chapter reviews the recent development on hydrogen bonded supramolecular low molecular weight liquid crystals (LCs), including hydrogen bonded rodlike and bent-shaped supramolecular LCs, columnar LCs, as well as nonconventional liquid crystals. IntroductionLiquid crystals (LCs) combine order and mobility on a molecular level and are important both in material and life science [1][2][3][4][5][6][7][8][9]. Different liquid crystalline phases have provided new methods for the design of supramolecular materials [10][11][12][13]. Nematic phases have found widely commercial applications as displays for computers and telecommunications [14], lamellar, columnar, micellar, and bicontinuous cubic phases and even more complicated new phases have also found wide applications as advanced materials [12,[15][16][17].Supramolecular liquid crystals can be obtained through hydrogen bonding, which was first introduced by Kato, and Lehn [21]. They exhibit a variety of physical properties, which make them attractive for applications in the field of nanoscience, materials, and biology and offer a very elegant and effective approach to adding functionalization in a controllable and convenient way to the molecular architecture. Complex 1 that exhibits smectic and nematic phases [18] and complex 2 that shows a columnar phase [21] are the two earliest examples for supramolecular hydrogen bonded liquid crystals. The design principle of hydrogen bonded supramolecule was also applied to prepare side-chain polymers 3 [19,20] and main-chain liquid crystal polymer 4 [22] and 5 [23], in this way the field of supramolecular polymers was introduced [24][25][26].

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Highly fluorescent columnar liquid crystals with elliptical molecular shape: oblique molecular stacking and excited-state intramolecular proton-transfer fluorescence

Cited by 71 publications

References 45 publications

Desymmetrization of 3,3′‐Bis(acylamino)‐2,2′‐bipyridine‐Based Discotics: The High Fidelity of Their Self‐Assembly Behavior in the Liquid‐Crystalline State and in Solution

Desymmetrization of 3,3′‐Bis(acylamino)‐2,2′‐bipyridine‐Based Discotics: The High Fidelity of Their Self‐Assembly Behavior in the Liquid‐Crystalline State and in Solution

Advanced Organic Optoelectronic Materials: Harnessing Excited‐State Intramolecular Proton Transfer (ESIPT) Process

Hydrogen Bonding for Supramolecular Liquid Crystals

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