86-28-2Relevant academic research and scientific papers
Push-pull fluorophores with viscosity dependent and aggregation induced emissions insensitive to polarity
Telore, Rahul D.,Satam, Manjaree A.,Sekar, Nagaiyan
, p. 359 - 367 (2015)
Abstract A series of push-pull chromophoric extended styryls from 5,5′-(9-ethyl-9H-carbazole-3,6-diyl)bis(2-morpholinothiazole-4-carbaldehyde) were synthesized by Knoevenagal condensation reaction with active methylene compounds. The intermediate carbaldehyde was synthesized from carbazole through multistep reactions. The intramolecular charge transfer of synthesized highly conjugated symmetrical D-π-A (D-donor, A-acceptor) extended styryls with rigid structure have been investigated by means of photophysical properties. The photophysical properties like absorption, emission and quantum yield of styryl derivatives were evaluated in various solvents of different polarities. All these synthesized extended styryls have exhibited aggregation induced emission with enhanced fluorescence intensity. This series of compounds can also be used as fluorescence molecular rotors for viscosity sensing. The sensitivity of viscosity towards UV absorption as well as fluorescence emission has also been investigated.
Initiation and propagation rate constants for the cationic polymerization of N-vinylcarbazole
Schimmel, Holger,Ofial, Armin R.,Mayr, Herbert
, p. 5454 - 5458 (2002)
Initiation and propagation rate constants for the cationic polymerization of N-vinylcarbazole were discussed. Benzhydryl cations were used as reference electrophiles to determine the reactivity parameters. All reactions were undertaken under dry, oxygenfr
Fluorescence Quenching Mechanism of Aromatic Hydrocarbons by Closed-Shell Heavy Metal Ions in Aqueous and Organic Solutions
Masuhara, Hiroshi,Shioyama, Hiroshi,Saito, Tokashi,Hamada, Kei,Yasoshima, Seikichi,Mataga, Noboru
, p. 5868 - 5873 (1984)
Fluorescence quenching rate constants of some aromatic hydrocarbons by Zn2+, Ag+, Cd2+, In3+, Sn2+, Cs+, Hg2+, Tl+, and Pb2+ were determined in aqueous and N,N-dimethylformamide solutions.Paramagnetic interactions, the heavy atom effect, and electron transfer were excluded as a possible quenching mechanism.N2 gas laser photolysis studies revealed that a cation radical of the fluorescer was detected only N-ethylcarbazole quenched by Ag+, Pb2+, and Hg2+ in N,N-dimethylformamide and for 1-pyrenesulfonic acid by Hg2+ in water.All other systems yielded the triplet state of the fluorescer quantitatively.The intermediates observed in the microsecond time region are the transient species with the lowest free energy.Picosecond laser photolysis of the Ag+ and Pb2+ quencher systems in N,N-dimethylformamide confirmed directly that the triplet state is induced by fluorescence quenching.On the basis of these results, it has been concluded that fluorescence quenching is due to nonfluorescent complex formation followed by rapid intersystem crossing.The electronic and geometrical structures of this complex were considered and compared to the excited aromatic hydrocarbon-halogen anion systems.
Dehydrogenation of dodecahydro-N-ethylcarbazole on Pt(111)
Gleichweit, Christoph,Amende, Max,Schernich, Stefan,Zhao, Wei,Lorenz, Michael P. A.,Hoefert, Oliver,Brueckner, Nicole,Wasserscheid, Peter,Libuda, Joerg,Steinrueck, Hans-Peter,Papp, Christian
, p. 974 - 977 (2013)
Sloshing hydrogen: Liquid organic hydrogen carriers are high-boiling organic molecules, which can be reversibly hydrogenated and dehydrogenated in catalytic processes and are, therefore, a promising chemical hydrogen storage material. One of the promising candidates is the pair N-ethylcarbazole/perhydro- N-ethylcarbazole (NEC/H12-NEC). The dehydrogenation and possible side reactions on a Pt(111) surface are evaluated in unprecedented detail. Copyright
Fabrication of Eu(III) complex doped nanofibrous membranes and their oxygen-sensing properties
Songzhu, Lin,Xiangting, Dong,Jinxian, Wang,Guixia, Liu,Wenshen, Yu,Ruokun, Jia
, p. 885 - 889 (2010)
In this paper, we report the synthesis, characterization, and photophysical properties of Eu(TTA)3ECIP, where TTA = 2-thenoyltrifluoroacetonate, and ECIP = 1-ethyl-2-(N-ethyl-carbazole-yl-4-)imidazo[4,5-f]1,10- phenanthroline. Its elementary application for oxygen-sensing application is also investigated by doping it into a polymer matrix of polystyrene (PS). Experimental data suggest that the 2.5 wt% doped Eu(TTA)3ECIP/PS nanofibrous membrane exhibits a high sensitivity of 3.4 towards oxygen with a good linear relationship of R2 = 0.9962. In addition, the 2.5 wt% doped Eu(TTA)3ECIP/PS nanofibrous membrane owns a quick response of 8 s towards oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(TTA) 3ECIP and Eu(TTA)3ECIP/PS system are promising candidates for oxygen-sensing optical sensors.
5-(N-Ethylcarbazol-3-yl)thiophene-2-carbaldehyde (ECTC): A novel fluorescent sensor for ferric ion
Zhang, Qiang,Wei, Huaixin,Zhai, Rongjia,Ji, Zhongling,Qi, Yu,Zhao, Xin
, p. 287 - 290 (2016)
5-(N-Ethylcarbazol-3-yl)thiophene-2-carbaldehyde (ECTC), was synthesized by Suzuki coupling reaction and characterized by 1H NMR, 13C NMR and elemental analysis. This compound strongly quenches fluorescence of Fe3+ ion, whereas almost no quenching is observed in the presence of other metal ions including Na+, K+, Mg2+, Ca2+, Cu2+, Mn2+ and Co2+. Under optimized conditions, the fluorescence intensity of ECTC is quenched in a linear fashion by Fe3+ ion in a wide range of 0.1 μm-10 μm with the limit of detection below 0.1 μm.
NLOphoric 3,6-di(substituted quinoxalin) Carbazoles – Synthesis, Photophysical Properties and DFT Studies
Telore, Rahul D.,Jadhav, Amol G.,Sekar, Nagaiyan
, p. 1531 - 1540 (2017)
Synthesis of novel 3,6-di(substituted quinoxalin) carbazole fluorophores by the condensation of 1,1′-(9-ethyl-9H-carbazole-3,6-diyl)bis(2-bromoethanone) with methyl, chloro and unsubstituted o-phenylenediamine is presented. Synthesized derivatives are well characterized by 1H NMR, 13C NMR, FTIR and Mass spectroscopy. Photophysical studies are carried out using solvents of varying polarities revealed positive solvatochromism and intramolecular charge transfer from carbazole (Donor) to quinoxalin (Acceptor). Intramolecular charge transfer properties are correlated by dipole moment changes and different polarity functions like Lippert–Mataga, Bilot-Kawski, Bakhshiev and Liptay plots with very good regression factors. Mulliken hush-analysis further support charge transfer characteristic. Linear and Nonlinear optical properties are explained by solvatochromic data using two-level quantum mechanical model and are correlated with computational calculations using density functional theory at B3LYP/6-31G(d) level. First hyperpolarizability value of all the synthesized compounds is found to be greater than urea by >333 times. Moreover, increase of hyperpolarizability values from non-polar to polar solvents are in good correlation with the significant charge transfer characteristic in polar solvents.
The synthesis of a series of fluorescent emitters and their application for dye lasing and cation sensing
Cang, Sheng,Liu, Liang,Tian, Yaqiang,Yang, Zixuan,Zhang, Leiyu
, (2021)
The following paper reported four carbazole-modified fluorescent emitters. Their molecular structure and electronic transition were analyzed via their single crystal and theoretical calculation. Their photophysical parameters, including absorption, emission and quantum yield, were determined and discussed. It was found that the emission performance of benzo-thiazole-based dyes was better than that of benzo-imidazole-based dyes, owing to the electron-donating effect from the S atom. Upon the presence of metal cations, these photophysical parameters were re-measured. Benzo-thiazole-based dyes were found insensitive towards most metal cations, while benzo-imidazole-based dyes showed obvious photophysical variation upon these metal cations, including absorption red shift and emission quenching. Detailed sensing performance of a representative dye was discussed. A linear working curve with good selectivity was finally observed. Its sensing mechanism was confirmed as the coordination between metal cation and deprotonated benzo-imidazole group. Benzo-thiazole-based dyes showed amplified spontaneous emission (ASE) behavior, with threshold energy of ~220 μJ. Given the optimal condition, a highest ASE efficiency of ~2% was observed, with FWHM value of 6 nm and emission peak of 435 nm. The major novelty and advancement of these fluorescent dyes shall be the stable ASE output (dye 4) under UV excitation and the linear sensing curve with good selectivity (dye 3), which was a hard task for emission turn off sensing probes. We attributed its causation to the valent-recognizing sensing mechanism.
Carbazole-based semicarbazones and hydrazones as multifunctional anti-Alzheimer agents
Chaudhary, Bharat N.,Gandhi, Bhumi,Kanhed, Ashish M.,Patel, Dushyant V.,Patel, Kirti V.,Patel, Kishan B.,Patel, Nirav R.,Prajapati, Navnit K.,Shah, Bhavik S.,Teli, Divya M.,Yadav, Mange Ram
, (2021/07/14)
With the aim to combat a multi-faceted neurodegenerative Alzheimer’s disease (AD), a series of carbazole-based semicarbazide and hydrazide derivatives were designed, synthesized and assessed for their cholinesterase (ChE) inhibitory, antioxidant and biometal chelating activity. Among them, (E)-2-((9-ethyl-9H-carbazol-3-yl)methylene)-N-(pyridin-2-yl)hydrazinecarbothioamide (62) and (E)-2-((9-ethyl-9H-carbazol-3-yl)methylene)-N-(5-chloropyridin-2-yl)hydrazinecarbothioamide (63) emerged as the premier candidates with good ChE inhibitory activities (IC50 values of 1.37 μM and 1.18 μM for hAChE, IC50 values of 2.69 μM and 3.31 μM for EqBuChE, respectively). All the test compounds displayed excellent antioxidant activity (reduction percentage of DPPH values for compounds (62) and (63) were 85.67% and 84.49%, respectively at 100 μM concentration). Compounds (62) and (63) conferred specific copper ion chelating property in metal chelation study. Molecular docking studies of compounds (62) and (63) indicate strong interactions within the active sites of both the ChE enzymes. Besides that, these compounds also exhibited significant in silico drug-like pharmacokinetic properties. Thus, taken together, they can serve as a starting point in the designing of multifunctional ligands in pursuit of potential anti-AD agents that might further prevent the progression of ADs. Communicated by Ramaswamy H. Sarma.
A general strategy to increase emission shift of two-photon ratiometric pH probes using a reversible intramolecular reaction of spiro-oxazolidine
He, Xiuquan,Tian, Minggang,Yang, Rui,Yu, Xiaoqiang,Zhang, Huamiao
supporting information, (2020/10/18)
Fluorescent pH probes have been served as powerful tools in biological and pathological studies in recent years due to the important roles of pH values in various physiological processes. Although plenty of pH probes have been delivered, development of two-photon ratiometric pH probes with large emission shift for detecting the variation of intracellular pH values is still a greatly challenging task. To address this concern, in this work, we have discovered a general strategy designing pH probes by means of a pH-dependent reversible intramolecular reaction of spiro-oxazolidine which can efficiently change their conjugation length and the electronic effect concurrently. To display the generality of the strategy, we have synthesized six pH probes, and all these probes exhibit short emission in basic conditions and dramatically red-shifted emission in acid environments. The emission shift of the six probes is more than 150 nm and even up to 210 nm, much larger than shift of all commercial and reported pH probes. The chemical sensing mechanism of intramolecular ring opening/closing reaction of spiro-oxazolidine has been confirmed with 1H NMR spectra and density functional theory (DFT) calculations. Finally, we have used one of six with one- and two-photon properties to successfully image lysosomal pH changes under confocal and two-photon microscopes in a ratiometric manner. We believed that this spiro-oxazolidine strategy can serve as a general and powerful platform for the design of ideal pH probes.
