A novel star-shaped Schiff base compound: Synthesis, properties and application in w-LEDs

Fang, Wenyan; Cao, Zhi; Liu, Qiman; Chu, Yi-Han; Zhu, Hanfei; Zhou, Weiwei; Yang, Jiaxiang

doi:10.1016/j.rio.2022.100228

Cited by 10 publications

(6 citation statements)

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“…In fact, higher current is accompanied by higher voltage and power, which naturally leads to an increase in emission intensity. However, the luminous efficiency (LE) is inevitably reduced because of the efficiency drop of blue-emitting chips at high current density . Therefore, the LE and photoelectric efficiency (PE) of TP 6- SA and TP 6- S LED devices show a decreasing trend with the increase of current density.…”

Section: Resultsmentioning

confidence: 99%

Dual-State Fluorescence in Some Salicylaldehyde-triphenylene Discotic Liquid Crystal Derivatives Induced by Excited State Intramolecular Proton Transfer

Zeng,

Wang,

Wang

et al. 2024

Chem. Mater.

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A new family of excited state intramolecular proton transfer (ESIPT) molecules based on the enol/ketone tautomerism is reported. The molecules were designed to display columnar mesophases and consist of the archetypical 3,6,7,10,11-penta(alkoxy)triphenylene discotic core functionalized in the vacant "2-position" by a salicylaldehyde group (TPn-SA). For comparison and confirmation that the ESIPT effect is solely due to the salicylaldehyde group, structurally related triphenylene derivatives bearing benzaldehyde (TPn-S) or aldehyde (TPS6) side groups were also synthesized. These molecules were synthesized either by Suzuki−Miyaura cross-coupling (TPn-SA, TPn-S) or by the Bouveault aldehyde synthesis (Ar−Li and DMF, TPS6) in overall good yields. All triphenylene compounds show an enantiotropic columnar hexagonal mesophase over large temperature range. Furthermore, TPn-SA compounds undergo a mesophase to crystalline phase transformation upon UV light irradiation at 365 nm, caused by ESIPT-induced enol− ketone tautomerism. TP12-SA also self-assembles into room temperature gels in toluene and ethyl acetate at rather low critical gel concentration. TPn-SA and TPn-S present strong fluorescence in both solution and solid state, with fluorescence quantum yields for the TPn-SA compounds around ∼20%; TPS6, in contrast, does not show fluorescence in solid state because of aggregation-caused quenching. The dual emission observed for TPn-SA was supported by DFT calculation. The ketone emission is dominant in nonpolar solvents and aggregated states, while the enol emission is dominant in polar solvents or in dilute solutions. Finally, the performances of TP6-SA and TP6-S in solid-state lighting LED devices have been investigated.

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Section: Resultsmentioning

confidence: 99%

Dual-State Fluorescence in Some Salicylaldehyde-triphenylene Discotic Liquid Crystal Derivatives Induced by Excited State Intramolecular Proton Transfer

Zeng,

Wang,

Wang

et al. 2024

Chem. Mater.

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“…early in the literature . Organic NLO materials generally contain donor (D)–acceptor (A) groups linked through a π-electronic bridge enhancing molecular polarizability and getting good nonlinear response . Schiff bases and their complexes have also gained great attention as nonlinear materials due to their extensive π-conjugation and synthetic flexibility. − …”

Section: Introductionmentioning

confidence: 99%

“… 8 They are called imines or azomethines, and they have gained the attention of researchers due to their ease in synthesis and complex forming ability with almost all metals. 9 Schiff bases are widely used in various fields like dyes and pigments, catalysis, 10 optical chemical sensors, 11 cell imaging, 12 solar energy applications, 10 corrosion inhibition, 13 LED applications, 14 renewable energy materials, 15 and so on. The basic concept of Schiff base chemistry is profusely utilized to synthesize modern materials like COFs 16 and MOFs, 17 and it provides key aspects to enhance physiochemical properties and also sensing abilities.…”

Section: Introductionmentioning

confidence: 99%

“…7 Organic NLO materials generally contain donor (D)−acceptor (A) groups linked through a πelectronic bridge enhancing molecular polarizability and getting good nonlinear response. 14 Schiff bases and their complexes have also gained great attention as nonlinear materials due to their extensive π-conjugation and synthetic flexibility. 28−31 Among the organic classes, the 4-amino antipyrine (4AAP) is an excellent heterocyclic molecule capable of forming Schiffbase-type ligands used to synthesize a variety of chelating metal complexes.…”

Section: Introductionmentioning

confidence: 99%

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Study of the Crystal Architecture, Optoelectronic Characteristics, and Nonlinear Optical Properties of 4-Amino Antipyrine Schiff Bases

et al. 2023

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Two Schiff bases, (E)-4-((2-chlorobenzylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (4AAPOCB) and (E)-4-((4-chlorobenzylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (4AAPPCB), have been synthesized and grown as single crystals. Single-crystal X-ray diffraction analysis was employed to determine the crystal structure of the compounds, and the results suggest that the compounds crystallized into an orthorhombic crystal system having P2 1 2 1 2 1 and Pbca space groups, respectively. Further, the crystallinity of the compounds was analyzed by the PXRD technique. The UV−vis−NIR spectra of the compounds demonstrate excellent transmittance in the entire visible region. The lower cutoff wavelengths of the compounds were determined to be 338 and 333 nm, respectively; additionally, optical band gaps of the compounds found were 4.60 and 4.35 eV. FTIR and NMR ( 1 H and 13 C) spectral techniques were utilized to analyze the molecular structure of the compounds. The compounds emit photoluminescence with broad emission bands with centers at 401 and 418 nm. The thermal stability and phase transitions were assessed through thermogravimetric methods. The phase transition prior to melting was indicated by the endothermic event at around 190 °C in the DTA curves of both crystals, and the same was observed in the DSC curves. The second harmonic efficiencies of the powdered compounds I and II were found to be 3.52 and 1.13 times better than that of the standard reference KDP. The 4AAPOCB and 4AAPPCB compounds showed isotropic polarizability amplitudes of 46.02 × 10 −24 and 46.52 × 10 −24 esu, respectively. The calculation of linear polarizability and NLO second-order polarizability (β) along with other optical parameters was performed for optimized geometries. The nonzero amplitudes of the average β values for compounds 4AAPOCB and 4AAPPCB were found to be 14.74 × 10 −30 and 8.10 × 10 −30 esu, respectively, which show a decent potential of the synthesized molecules for NLO applications. The calculated β amplitudes were further explained based on calculated electronic parameters like molecular electrostatic potentials, frontier molecular orbitals, molecular orbital energies, transition energies, oscillator strengths, and unit spherical representation of NLO polarizability. The current analysis emphasizes the significance of synthesized compounds as prospective candidates for optical and NLO applications through the use of experiments and quantum computations.

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“…尤其在新冠病毒流行的大背景下, 其在生物医学领域的开发设计更是受到了广大科研人员的青睐 [7][8] . 其中, 含杂原子结构单元 [9][10] 凭借杂原子的电子效应与配位能力被广泛用于设计刺激响应分子. 在众多结构单元中, 1,3,5-均三嗪的环状共轭结构有助于拓展共轭体系以带来发光特性, 而 N 原子大电负性的电子效应决定了均三嗪是优异的电子受体, 能够用于构筑分子内电荷转移的供体-受体(D-A)分子, 进而表现出荧光多变的性质 [11] .…”

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Star-shaped Triphenylene-triazine Multi-stimuli Responsive Discotic Liquid Crystals: Synthesis, Properties and Applications

Chongyang¹,

Hu²,

Wang³

et al. 2023

Acta Chimica Sinica

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The electronic and optical properties of π-conjugated materials are determined by their molecular structures and supramolecular architectures. Discotic liquid crystals consist of π-conjugated aromatic core and peripheral alkyl chains, they self-organize into two-dimensional discotic columnar mesophase, which can be applied as charge carrier transport channel in optical and electronic thin-film devices. Order and dynamics are two unique features of discotic liquid crystalline semiconductors. Three star-shaped 1,3,5-triazine-triphenylene discotic liquid crystals TPPTn (n＝6, 8, 12) were synthesized by Suzuki-Miyaura cross-coupling reaction and characterized. Thermogravimetric analysis (TGA) shows that TPPTn have good thermal stability, and their thermal decomposition temperatures were higher than 350 ℃. The ultraviolet-visible (UV-Vis) absorption spectra and fluorescence spectra showed that they have outstanding fluorescence emissions in solution, thin film and even in solid state, and the length of alkoxy chain affects a little the fluorescence properties of the film or solid state by affecting the molecular aggregation. TPPTn have the aggregation-induced emission (AIE) effect: longer the alkoxy chain, more obvious the AIE phenomenon, this AIE effectively overcomes the disadvantage of aggregation caused quenching (ACQ) of π-extended discotic liquid crystalline molecules. Further, TPPT6 exhibits significant solvatochromism from blue to orange with the increasing of solvent polarity, due to the intramolecular charge transfer (ICT), which provides possibility for visual recognition of solvent polarity. The fluorescent emission absolute quantum yield is up to 43%. What is more, TPPT6 exhibits a temperature-responsive fluorescence enhancement with increasing temperature in solution, which is different from the temperature quenching of traditional molecules, and the fluorescence exhibits a reversible switching from green to blue with increasing/decreasing of temperature. TPPT6 also has obvious acid-base stimuli-responsive fluorescent response by CF3COOH and Et3N. 1 H NMR titration proves that the protonation of triazine core is the mechanism to acid discoloration. Based on the acid-base stimuli response phenomena, two kinds of fluorescent safety inks have been designed and

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A novel star-shaped Schiff base compound: Synthesis, properties and application in w-LEDs

Cited by 10 publications

References 50 publications

Dual-State Fluorescence in Some Salicylaldehyde-triphenylene Discotic Liquid Crystal Derivatives Induced by Excited State Intramolecular Proton Transfer

Dual-State Fluorescence in Some Salicylaldehyde-triphenylene Discotic Liquid Crystal Derivatives Induced by Excited State Intramolecular Proton Transfer

Study of the Crystal Architecture, Optoelectronic Characteristics, and Nonlinear Optical Properties of 4-Amino Antipyrine Schiff Bases

Star-shaped Triphenylene-triazine Multi-stimuli Responsive Discotic Liquid Crystals: Synthesis, Properties and Applications

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