- Impact of Methoxy Substituents on Thermally Activated Delayed Fluorescence and Room-Temperature Phosphorescence in All-Organic Donor-Acceptor Systems
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Thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) are known to occur in organic D-A-D and D-A systems where the donor group contains the phenothiazine unit and the acceptor is dibenzothiophene-S,S-dioxide. This study reports the synthesis and characterization of one new D-A and four new D-A-D systems with methoxy groups on the phenothiazine to examine their effect on emission properties in the zeonex matrix. X-ray analysis and highly specialized NMR techniques were used to characterize asymmetric methoxy-substituted derivative 3b, which is chiral at N because of an extremely high flipping barrier at the phenothiazine N atom. Based on hybrid-density functional theory computations, the methoxy substituents tune the relative stabilities of the axial conformers with respect to equatorial conformers of the phenothiazine units, depending on their substitution position. This conformational effect significantly influences both TADF and RTP contributions compared to the parent D-A-D system. It is also demonstrated that the equatorial forms of D-A-D and D-A systems in zeonex exhibit TADF. Additionally, the methoxy groups promote luminescence in D-A-D systems where only axial conformers exist. This work reveals further design opportunities for more efficient TADF and RTP molecules.
- Ward, Jonathan S.,Nobuyasu, Roberto S.,Fox, Mark A.,Aguilar, Juan A.,Hall, David,Batsanov, Andrei S.,Ren, Zhongjie,Dias, Fernando B.,Bryce, Martin R.
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p. 3801 - 3816
(2019/04/03)
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- Synthesis of N-Heterocycles by Dehydrogenative Annulation of N-Allyl Amides with 1,3-Dicarbonyl Compounds
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Dehydrogenative annulation under oxidizing reagent-free conditions is an ideal strategy to construct cyclic structures. Reported herein is an unprecedented synthesis of pyrrolidine and tetrahydropyridine derivatives through electrochemical dehydrogenative annulation of N-allyl amides with 1,3-dicarbonyl compounds. The electrolytic method employs an organic redox catalyst, which obviates the need for oxidizing reagents and transition-metal catalysts. In these reactions, the N-allyl amides serve as a four-atom donor to react with dimethyl malonate to give pyrrolidines by a (4+1) annulation, or with β-ketoesters to afford tetrahydropyridine derivatives by a (4+2) annulation.
- Wu, Zheng-Jian,Li, Shi-Rui,Xu, Hai-Chao
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supporting information
p. 14070 - 14074
(2018/10/15)
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- On how electron density affects the redox stability of phenothiazine sensitizers on semiconducting surfaces
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The stabilities of three organic dyes that differ only by two substituents (-OMe,-H and-Br) about the phenothiazine donor unit were evaluated when immobilized on a semiconductor surface. All three dyes delivered modest power conversion efficiencies (PCEs) in the dye-sensitized solar cell (DSSC), but maintained 75% of their initial PCE over 300 h of sustained simulated sunlight. Electron-donating substituents increased the stability of the phenothiazine radical unit created after light-induced charge injection into the semiconductor; however, this did not translate to higher DSSC stability, which appears to be more sensitive to the basicity of the anchoring group for this series.
- Chiykowski, Valerie A.,Lam, Brian,Du, Chuan,Berlinguette, Curtis P.
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supporting information
p. 2547 - 2550
(2017/03/09)
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- Comparative analysis of triarylamine and phenothiazine sensitizer donor units in dye-sensitized solar cells
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A homologous set of dyes that differ only in the donor fragments, namely phenothiazine (PTZ) and triarylamine (TPA) units, were evaluated in dye-sensitized solar cells (DSSCs). The novel PTZ-based dye differs from the TPA-based dye in that it contains a sulfur bridge that planarizes two aromatic rings and enables higher dye loading and higher stability in the oxidized form. These positive features notwithstanding, the superior absorptivity of devices sensitized by TPA-based dyes resulted in significantly higher power conversion efficiencies (PCEs) than those sensitized by PTZ-based dyes.
- Chiykowski, Valerie A.,Lam, Brian,Du, Chuan,Berlinguette, Curtis P.
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supporting information
p. 2367 - 2370
(2017/02/23)
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- A method of synthesizing phenoxthine compounds
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The invention develops a method for synthesizing phenothiazine compounds by using benzothiazole and derivatives thereof as well as 1-bromo-2-iodobenzene and derivatives thereof as raw materials and copper or copper salt/N-alkoxy-1H-pyrrolic amide system as a copper catalyst. The method is a brand-new method for synthesizing phenothiazine compounds. The method has the characteristics of low temperature, short reaction time, low solvent toxicity and wide substrate adaptability, and has wide application prospects in the aspect of preparation of medicines, pesticides and materials.
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Paragraph 0064; 0065; 0066; 0067
(2016/10/17)
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- Copper-Catalyzed Domino Reactions for the Synthesis of Phenothiazines
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A method for the one-pot synthesis of phenothiazines from benzothiazoles and aryl ortho-dihalides was explored. Preliminary work on the mechanism of the reaction suggested that it follows a domino process, including the hydrolysis of benzothiazoles followed by C-S coupling and C-N coupling. The low loading of the catalyst system (5 mol-% for both copper and ligand), the mild experimental conditions (90 °C, 12 h), and the use of a green reaction medium make this synthesis very attractive to academia and industry. A copper-catalyzed domino reaction consisting of the hydrolysis of benzothiazoles followed by C-S and C-N couplings for the synthesis of phenothiazines from benzothiazoles and aryl ortho-dihalides is described. The low loading of the catalyst system, mild experimental conditions, and the use of polyethylene glycol as the solvent make this synthetic approach very attractive to academia and industry.
- Huang, Manna,Huang, Dongting,Zhu, Xinhai,Wan, Yiqian
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supporting information
p. 4835 - 4839
(2015/08/03)
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- TRICYCLIC HETEROAROMATIC COMPOUNDS AS ALPHA-SYNUCLEIN LIGANDS
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Derivatives of phenothiazine, phenoxazine, and phenazine compounds and their use as α-synuclein ligands are described. Also described are methods of using these compounds and their radiolabeled analogs for the detection, monitoring, and treatment of synucleinopathies, including Parkinson's disease.
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- Synthesis and in vitro evaluation of α-synuclein ligands
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Accumulation of misfolded α-synuclein in Lewy bodies and Lewy neurites is the pathological hallmark of Parkinson's disease (PD). To identify ligands having high binding potency toward aggregated α-synuclein, we synthesized a series of phenothiazine derivatives and assessed their binding affinity to recombinant α-synuclein fibrils using a fluorescent thioflavin T competition assay. Among 16 new analogues, the in vitro data suggest that compound 11b has high affinity to α-synuclein fibrils (Ki = 32.10 ± 1.25 nM) and compounds 11d, 16a and16b have moderate affinity to α-synuclein fibrils (Ki ≈ 50-100 nM). Further optimization of the structure of these analogues may yield compounds with high affinity and selectivity for aggregated α-synuclein.
- Yu, Lihai,Cui, Jinquan,Padakanti, Prashanth K.,Engel, Laura,Bagchi, Devika P.,Kotzbauer, Paul T.,Tu, Zhude
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experimental part
p. 4625 - 4634
(2012/09/05)
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- Tri- and tetracyclic compounds
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There are described compounds of the formula STR1 Wherein the variables have been defined herein. The compounds are useful as research tools in the determination of biologically active peptides sequences and also potentially suitable as medicaments, some of them being useful in the prevention or control of the formation of blood platelet thrombi, and some compounds are useful as intermediates.
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