- Development of colloidally stable carbazole-based fluorescent nanoaggregates
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Fluorescent nanomaterials require high colloidal stability for effective use in imaging and sensing applications. We herein report the synthesis of carbazole-based organic fluorescent nanoaggregates, and demonstrate the superior colloidal stability of alkyl-substituted dye aggregates over their non-alkylated analogs. The role of alkyl chains in self-assembly and stability of such nanoaggregates is discussed based on both experimental and molecular dynamics simulation data, and spectral characteristics of the precursor dyes and their aggregates are described. The obtained results provide new insights on development of colloidally stable organic fluorescent nanomaterials with low polydispersity.
- Svechkarev, Denis,Kyrychenko, Alexander,Payne, William M.,Mohs, Aaron M.
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- Pyridazine–carbazole based fluorescent probes for volatile acid detection
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Stimuli-responsive materials based on donor–acceptor systems have great potential for sensing applications, including in the solid state. Herein, two push–pull-type molecules, 3,6-di(9H-carbazol-9-yl)pyridazine (CzPyr–H) and 3,6-bis(3,6-dimethoxy-9H-carbazol-9-yl)pyridazine (CzPyr–OMe), each of which contain two carbazole donors and a pyridazine acceptor, were designed and synthesized. The photophysical properties of CzPyr–H and CzPyr–OMe were systematically explored with the aim of switching the absorption and emission properties using trifluoroacetic acid (TFA) as an external analyte, thus realizing volatile acid sensing. The protonation of the central pyridazine unit led to a broad absorption band at longer wavelengths owing to intramolecular charge transfer (ICT), and the emission intensity gradually decreased with increasing TFA concentration. Density functional theory calculations of the HOMO–LUMO energy gaps and orbital distributions of CzPyr–H and CzPyr–OMe as well as their protonated forms, CzPyr–H(H+) and CzPyr–OMe(H+), confirmed that charge transfer occurred in the protonated species. In their aggregated solid states, both compounds showed interesting emission properties including aggregation-enhanced emission (AEE). Utilizing their TFA sensitivity and the AEE phenomenon, CzPyr–H and CzPyr–OMe were successfully applied as fluorescent probes for volatile acid detection and as security ink for information encryption on paper.
- Han, Won-Sik,Kim, Seung-Hwan,Lee, Sohee,Lee, Sunhee,Lee, Yeeun,Lee, Yong Sup,Wang, Kang-Kyun,Yang, Kwang-Hwan
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- Enhancement of redox stability and electrochromic performance of aromatic polyamides by incorporation of (3,6-dimethoxycarbazol-9-yl)-triphenylamine units
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New series aromatic polyamides with (carbazol-9-yl)triphenylamine units were synthesized from a newly synthesized diamine monomer, 4,4′-diamino- 4″-(3,6-dimethoxycarbazol-9-yl) triphenylamine, and aromatic dicarboxylic acids via the phosphorylation polyamidation technique. These polyamides exhibit good solubility in many organic solvents and can be solution-cast into flexible and strong films with high thermal stability. They show well-defined and reversible redox couples during oxidative scanning, with a strong color change from colorless neutral form to yellowish green and blue oxidized forms at applied potentials scanning from 0.0 to 1.3 V. They show enhanced redox-stability and electrochromic performance as compared to the corresponding analogs without methoxy substituents on the active sites of the carbazole unit. Copyright
- Wang, Hui-Min,Hsiao, Sheng-Huei
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- A star-shaped cyclopentadithiophene-based dopant-free hole-transport material for high-performance perovskite solar cells
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A new cyclopentadithiophene (CPDT)-based organic small molecule serves as an efficient dopant-free hole transport material (HTM) for perovskite solar cells (PSCs). Upon incorporation of two carbazole groups, the resulting CPDT-based HTM (C-CPDT) shows an impressive power conversion efficiency (PCE) of 19.68% with better stability compared with those of spiro-OMeTAD.
- Lee, Kun-Mu,Yang, Jui-Yu,Lai, Ping-Sheng,Luo, Ke-Jyun,Yang, Ting-Yu,Liau, Kang-Ling,Abate, Seid Yimer,Lin, Yan-Duo
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p. 6444 - 6447
(2021/07/02)
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- A simple strategy to achieve efficient thermally activated delayed fluorescent emitters via enhancing electron donating ability of donors
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Simultaneously achieving both effective reverse intersystem crossing (RISC) process and high values of radiative decay rate (kr)/photoluminescent quantum yield (PLQY) are critical for efficient thermally activated delayed fluorescent (TADF) emitters. The separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) through typical molecular geometry tuning method guarantees a small ΔEST but results in disfavored oscillator strength for fluorescent decay. Herein, a simple method is provided to facilitate the reverse intersystem crossing (RISC) of TADF emitters via enhancing electron donating property of donors rather than twisting the donor-acceptor configuration. Three molecules, namely Me-Cz, Me-MOC and Me-DOC, are designed and synthesized. The introduction of methoxy group enhances the electron-donating ability of carbazole. The stabilized charge transfer state features a reduced splitting energy between the first singlet and triplet excited state, thus activating TADF process. Consequently, the molecules Me-DOC and Me-MOC achieve good external quantum efficiency of 18.6% and 12.4% in electroluminescent devices.
- Li, Ganggang,Li, Jiafang,Li, Kai,Liu, He,Liu, Zhiwen,Wang, Zhiming,Yang, Chuluo,Zhan, Qun,Zhang, Bing,Zhou, Changjiang
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- One-pot synthesis of a white-light emissive bichromophore operated by aggregation-induced dual emission (AIDE) and partial energy transfer
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Merocyanine-triarylamine bichromophores are readily synthesized by sequentially Pd-catalyzed insertion-alkynylation-Michael-Suzuki four-component reactions. White-light emissive systems form upon aggregation in 1 : 99 and 0.1 : 99.9 vol percent CH2Cl2-cyclohexane mixtures, ascribed to aggregation-induced dual emission (AIDE) in combination with partial energy transfer between both chromophore units as supported by spectroscopic studies.
- Biesen, Lukas,Deni?en, Melanie,Hannen, Ricarda,Hoffmann, Katrin,Itskalov, Dana,Müller, Thomas J. J.,Nirmalananthan-Budau, Nithiya,Reiss, Guido J.,Resch-Genger, Ute
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supporting information
p. 7407 - 7410
(2020/07/15)
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- Methoxy- and tert-butyl-substituted meta-bis(N-carbazolyl)phenylenes as hosts for organic light-emitting diodes
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Two new analogues of a popular host material, meta-bis(N-carbazolyl)phenylene (mCP), bearing either methoxy- (mCP-OMe) or tert-butyl (mCP-t-Bu) substituents at C-3 and C-6 positions of carbazole moieties were synthesized and characterized. These materials exhibit higher glass-transition temperatures (79 and 145 °C) than mCP (67 °C). They show reversibility upon electrochemical oxidation while preserving high enough triplet energy levels (2.86 and 2.97 eV). The vacuum-deposited layer of mCP-t-Bu showed hole mobility of 8 × 10?3 cm2V?1s?1 at the electric field of 1.2 × 105 Vcm?1. This value is more than by one order of magnitude higher than that of mCP. The new compounds were tested as hosts for commercial emitters: blue phosphor, bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic), green and blue thermally-activated delayed fluorescence (TADF) emitters 1,2,3,5-tetrakis(9-carbazolyl)-4,6-dicyanobenzene (4CzIPN) and bis[4-(9,9-dimethyl-9,10-dihydroacridin-10-yl)phenyl]sulfone (DMAC-DPS). Blue phosphorescent OLED based on mCP-t-Bu as the host showed up to 22.0% external quantum efficiency. When doping 4CzIPN into mCP-OMe host, a broad emission with peaks at 388, 514, and 572 nm was observed.
- Keruckas, Jonas,Volyniuk, Dmytro,Simokaitiene, Jurate,Narbutaitis, Edgaras,Lazauskas, Algirdas,Lee, Pei-Hsi,Chiu, Tien-Lung,Lin, Chi-Feng,Arsenyan, Pavel,Lee, Jiun-Haw,Grazulevicius, Juozas V.
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p. 317 - 326
(2019/07/02)
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- Sterically Hindered Amination of Aryl Chlorides Catalyzed by a New Carbazolyl-Derived P,N-Ligand-Composed Palladium Complex
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A family of 2-(9 H -carbazol-9-yl)phenyl-based phosphine ligands were synthesized and their efficacy in promoting the steric hindered Buchwald-Hartwig amination was evaluated. In the presence of Pd(OAc) 2 (0.03-1.0 molpercent) associated with t
- Choy, Pui Ying,Kwong, Fuk Yee,Lai, Wing In,Leung, Man Pan
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supporting information
p. 2678 - 2686
(2019/06/19)
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- C-Terminal Bioconjugation of Peptides through Photoredox Catalyzed Decarboxylative Alkynylation
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We report the first decarboxylative alkynylation of the C-terminus of peptides starting from free carboxylic acids. The reaction is fast, metal-free, and proceeds cleanly to afford alkynylated peptides with a broad tolerance for the C-terminal amino acid. By the use of hypervalent iodine reagents, the introduction of a broad range of functional groups was successful. C-terminal selectivity was achieved by differentiation of the oxidation potentials of the carboxylic acids based on the use of fine-tuned organic dyes.
- Garreau, Marion,Le Vaillant, Franck,Waser, Jerome
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supporting information
p. 8182 - 8186
(2019/05/21)
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- Stimuli-Responsive Properties of Aggregation-Induced-Emission Compounds Containing a 9,10-Distyrylanthracene Moiety
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Two 9,10-distyrylanthracene-based luminophores exhibiting aggregation-induced emission and stimuli-responsive properties were synthesized. Seven- or five-color luminescence switching based on a single organic molecule was achieved for the first time. Thes
- Jia, Xiang-Rui,Yu, Hui-Juan,Chen, Jian,Gao, Wei-Jie,Fang, Jing-Kun,Qin, Yuan-Shou,Hu, Xiao-Kai,Shao, Guang
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supporting information
p. 19053 - 19059
(2018/11/23)
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- "on Water" Promoted Ullmann-Type C-N Bond-Forming Reactions: Application to Carbazole Alkaloids by Selective N-Arylation of Aminophenols
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The Ullmann-type cross coupling of a variety of aromatic, aliphatic amines with aryl halides is reported using a CuI-based catalytic system in combination with an easily accessible prolinamide ligand in aqueous media. The method is mild and tolerant to air, moisture, and a wide range of functional groups, providing a novel way to access a variety of aminated products. Secondary amines like heteroaromatic amines and nucleobases have also been used, affording the corresponding coupling products in good to excellent yields. Moreover, this method has been employed for chemoselective C-N arylation of aminophenols and further utilized for the synthesis of carbazole natural products, avoiding the protection and deprotection steps.
- Chakraborti, Gargi,Paladhi, Sushovan,Mandal, Tirtha,Dash, Jyotirmayee
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p. 7347 - 7359
(2018/07/29)
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- Photochemical C–H Activation: Generation of Indole and Carbazole Libraries, and First Total Synthesis of Clausenawalline D
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The photolysis of N-aryltriazoles and N-arylbenzotriazoles leads to indoles and carbazoles, respectively. Because libraries of triazoles can be accessed rapidly, for example by the copper-catalyzed [3+2] cycloaddition reaction between alkynes and azides, this reaction allows the preparation of indoles in a single operation, by the simultaneous photolysis of the precursor library. As an example of such a synthesis of carbazoles, we prepared for the first time clausenawalline D, an antimalarial alkaloid that was recently isolated.
- Alimi, Isak,Remy, Richard,Bochet, Christian G.
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p. 3197 - 3210
(2017/06/21)
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- Synthesis and properties of photocross-linkable carbazole dimers
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New carbazole-based monomers with two reactive functional groups such as epoxypropyl, oxetanyl and vinyloxethyl were synthesized and their cationic photopolymerization was performed. The monomer containing epoxypropyl groups exhibited the highest conversion in photopolymerization (78%). The monomers and polymers exhibited ability of glass formation with the glass transition temperatures up to 98?°C for low-molecular-weight compounds and those observed for polymers ranging from 89 to 150?°C. The synthesized derivatives absorb electromagnetic irradiation in the range of 200–390?nm with the band gaps of 3.14–3.16?eV. The compounds exhibit blue photoluminescence with the intensity maxima at 400?nm. The compounds were found to have high triplet energies of ca. 2.78?eV. The electron photoemission spectra of the layers of the synthesized compounds revealed ionization potentials of 5.20–5.37?eV. The time-of-flight hole drift mobilities of the layers of the compounds exceed 10??5?cm2/V?×?s at high electric fields.
- Simkus,Tomkeviciene,Volyniuk,Kostjuk,Grazulevicius
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- Photoinduced Charge-Transfer State of 4-Carbazolyl-3-(trifluoromethyl)benzoic Acid: Photophysical Property and Application to Reduction of Carbon?Halogen Bonds as a Sensitizer
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The photoinduced persistent intramolecular charge-transfer state of 4-carbazolyl-3-(trifluoromethyl)benzoic acid was confirmed. It showed a higher catalytic activity in terms of yield and selectivity in the photochemical reduction of alkyl halides compared to the parent carbazole. Even unactivated primary alkyl bromides could be reduced by this photocatalyst. The high catalytic activity is rationalized by considering the slower backward single-electron transfer owing to the spatial separation of the donor and acceptor subunits.
- Matsubara, Ryosuke,Shimada, Toshiyuki,Kobori, Yasuhiro,Yabuta, Tatsushi,Osakai, Toshiyuki,Hayashi, Masahiko
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supporting information
p. 2006 - 2010
(2016/07/28)
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- Synthesis of nitrocarbazole compounds and their electrocatalytic oxidation of alcohol
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Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation-reduction potential of the compounds were greatly affected by their substituents. The oxidation-reduction potential of the compound with an electron-donating group was negative, while that of the compound with an electron-withdrawing group on the carbazole framework was positive. The electrocatalytic oxidation activities of the nitrocarbazole compounds were investigated through cyclic voltammetry and controlled potential electrolysis at room temperature. The electrocatalysts showed excellent selectivity for p-methoxybenzyl alcohol, converting it to the corresponding aldehyde through electro-oxidation with just 2.5 mol% of the electrocatalysts presented. The electrocatalysts maintained their excellent electroredox activity following recycling.
- Zhu, Yinghong,Zhang, Jianqing,Chen, Ziying,Zhang, Anlun,Ma, Chunan
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p. 533 - 538
(2016/04/20)
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- Substituent effects on electrochemical and electrochromic properties of aromatic polyimides with 4-(carbazol-9-yl)triphenylamine moieties
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Three series of aromatic polyimides with 4-(carbazol-9-yl)triphenylamine moieties were prepared from the polycondensation reactions of 4,4′-diamino-4″-(carbazol-9-yl) triphenylamine (1), 4,4′-diamino-4″-(3,6-di-tert-butylcarbazol-9-yl)triphenylamine (t-Bu-1), and 4,4′-diamino-4″-(3,6-dimethoxycarbazol-9-yl) triphenylamine (MeO-1), respectively, with various commercially available tetracarboxylic dianhydrides. In addition to high thermal stability and good film-forming ability, the resulting polyimides exhibited an ambipolar electrochromic behavior. The polyimides based on t-Bu-1 and MeO-1 revealed higher redox-stability and enhanced electrochromic performance than the corresponding ones based on 1 because the active sites of their carbazole units are blocked with bulky t-butyl or electron-donating methoxy groups. 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1172-1184 Three series of 4-(carbazol-9-yl)triphenylamine-based aromatic polyimides are prepared by polycondensation of corresponding diamines with various commercially available tetracarboxylic dianhydrides. All the polyimides afford flexible and tough films with high thermal stability. The polymer films show ambipolar redox and multicolored electrochromic behaviors. During the electro-oxidation processes, the polyimides with t-butyl or methoxy substituents on the pendent carbazole unit exhibit enhanced electrochemical stability and electrochemical performance, as compared with the coresponding parent polyimides, because the electrochemically active sites of carbazole are blocked. Copyright
- Wang, Hui-Min,Hsiao, Sheng-Huei
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p. 1172 - 1184
(2014/03/21)
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- Toward polynuclear Ru-Cu catalytic dehydrogenative C-N bond formation, on the reactivity of carbazoles
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The cooperative action of Ru and Cu catalysts enables direct polynuclear C-H and N-H activation for the dehydrogenative N-carbazolation of carbazoles, selectively at the C1 position. Initial mechanistic experiments are presented and discussed.
- Louillat, Marie-Laure,Patureau, Frederic W.
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supporting information
p. 164 - 167
(2013/03/28)
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- Thermodynamics and conformations in the formation of excited states and their interconversions for twisted donor-substituted tridurylboranes
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We synthesized a series of donor-substituted tridurylboranes containing different types and number of chromophores including 1-pyrene (PB1-3), 3-carbazole (CBC1-3), or substituted p-carbazol-N-phenyl (CBN3a-c) as various donor-acceptor (D-A) molecules. The photophysical and electrochemical properties of these twisted D-A molecules were investigated by means of UV/Vis absorption and fluorescence spectroscopy as well as cyclic voltammetry (CV). Solvent polarity, viscosity, and temperature effects on the fluorescence emission reveal the existence of three types of excited states, and their equilibria and interconversions between three excited states. In increasing order of the charge-separated extent and the conformational change, three excited states are the locally excited (LE) state, the more planar intramolecular charge-transfer (ICT) state, and the more twisted ICT (TICT) state as compared to the ground state. The TICT state undergoes a conformational change with a higher energy barrier over the ICT state. The solvent polarity effect on the state conversion is opposite to the viscosity effect, and temperature effects derive from its resulting changes of polarity and viscosity. For example, the increase of the polarity of the solvent results in excited-state conversions from the LE state to the ICT state, and/or from the ICT to the TICT state, and an increased viscosity leads to the opposite conversions. On the basis of electrochemical and spectral data, thermodynamics of a possible ICT process were estimated, and correlated with the excited-state character. Finally, three excited states have been characterized by the conformation, the photophysical properties, and the thermodynamics of the ICT processes. Directed interconversion: Three types of excited states (LE, ICT, and TICT) in the photochemical processes of a series of synthesized tridurylboranes are characterized by the conformation, the photophysical properties, and the thermodynamics of the intramolecular charge-transfer process. Effects of the solvent polarity, the viscosity, and the temperature on the fluorescence spectra reveal the interconversion and equilibria between the excited states (see figure). Copyright
- Mao, Mao,Ren, Ming-Guang,Song, Qin-Hua
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supporting information
p. 15512 - 15522
(2013/01/15)
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- NOVEL OLIGOTHIOPHENE DERIVATIVES, THEIR PROCESS OF PREPARATION AND THEIR USES
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The present invention concerns novel oligothiophene derivatives bearing reactive functions, their process of preparation, their use for preparing electrically semi-conducting organic compounds, their preparation thereof and nanohybrid nanocomposite materi
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