1771-19-3Relevant articles and documents
Tuning Electron-Withdrawing Strength on Phenothiazine Derivatives: Achieving 100 % Photoluminescence Quantum Yield by NO2 Substitution
Chen, Meng-Chi,Lee, Yao-Lin,Huang, Zhi-Xuan,Chen, Deng-Gao,Chou, Pi-Tai
supporting information, p. 7124 - 7130 (2020/05/25)
The weak fluorescence (quantum yield 2) is a well-known fluorescence quencher. Interestingly, we obtained a highly fluorescent chromophore by combining these two moieties, forming 3-nitrophenothiazine (PTZ-NO2). For comparison, a series of PTZ derivatives bearing electron-withdrawing groups (EWGs; CN and CHO) or electron-donating groups (EDGs; OMe) at the 3-position have been designed and synthesized. The phenothiazines bearing EWGs exhibited enhanced emission compared with the parent PTZ or EDG derivatives. Computational approaches unveiled that for PTZ and PTZ-OMe, the transitions are from HOMOs dominated by π orbitals to LUMOs of mixed sulfur nonbonding–π* orbitals, and hence are partially forbidden. In contrast, the EWGs lower the energy level of the lone-pair electrons on the sulfur atom, thereby suppressing the mixing of the nonbonding orbital with the π* orbital in the LUMO, such that the allowed ππ* transition becomes dominant. This work thus demonstrates a judicious chemical design to fine-tune the transition character in PTZ analogues, with PTZ-NO2 attaining 100 % emission quantum yields in nonpolar solvent.
Copper-Catalyzed Domino Reactions for the Synthesis of Phenothiazines
Huang, Manna,Huang, Dongting,Zhu, Xinhai,Wan, Yiqian
supporting information, p. 4835 - 4839 (2015/08/03)
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.
Novel copper-catalyzed rearrangement of 2-aminobenzothiazoles to phenothiazines
Beresneva,Abele
, p. 1420 - 1422 (2013/04/24)
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