Chin. J. Org. Chem. ›› 2016, Vol. 36 ›› Issue (4): 803-811.DOI: 10.6023/cjoc201510008 Previous Articles     Next Articles

ARTICLE

10-甲基-10H-吩噻嗪-5,5-二氧化物衍生物的合成及其光物理和电化学性质

郑月游, 谢琼琳, 王炳喜   

  1. 福州大学材料科学与工程学院 福州 350116
  • 收稿日期:2015-10-09 修回日期:2015-12-01 出版日期:2016-04-25 发布日期:2015-12-15
  • 通讯作者: 王炳喜 E-mail:wangbx08@163.com
  • 基金资助:

    福州大学科技发展基金(No.2010XQ02)资助项目.

Synthesis and Photophysical and Electrochemical Properties of 10-Methyl-10H-phenothiazine-5,5-dioxide Derivatives

Zheng Yueyou, Xie Qionglin, Wang Bingxi   

  1. College of Materials Science and Engineering, Fuzhou University, Fuzhou 350116
  • Received:2015-10-09 Revised:2015-12-01 Online:2016-04-25 Published:2015-12-15
  • Supported by:

    Project supported by the Science and Technology Development Foundation of Fuzhou University (No. 2010XQ02).

Based on 10-methyl-10H-phenothiazine-5,5-dioxide unit as an acceptor and 9,10-dihydro-9,9-dimethyl-acridine (DMAC) or phenoxazine (PXZ) as donors, four intramolecular charge transfer (ICT) compounds were designed and synthesized by Buchwald-Hartwig cross coupling reactions. Their ground-state geometries were optimized with density functional theory (DFT) at B3LYP level and vertical transition energies were calculated using the optimal Hartree-Fock (HF) exchange method. Resulting compounds were characterized by fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography-mass (LC-MS) spectrometry and hybrid quadrupole time-of-flight mass spectrometry (QTOF). Their photophysical properties were systematically investigated. The results show that compound 2a has maximum emission wavelength (λmax) of 422 nm in toluene and its oxygen-free one has photoluminescence quantum yield (PLQY) of 0.367. Theλmax and PLQY for 1a and 1b are 455 nm, 0.083 and 511 nm, 0.098, respectively. Transient photoluminescence decay curves for 5 wt% 1a and 1b doped in PMMA films indicate that their delayed fluorescence lifetimes are 5.78 and 20.00 μs, respectively. According to the time-resolved fluorescence and phosphorescence spectra of 1a and 1b doped in PMMA films at 77 K, their energy gaps (ΔEST) between the lowest singlet state (S1) and the lowest triplet excited state (T1) are determined to be 0.203 and 0.177 eV, respectively, which are consistent with the theoretical values 0.232 and 0.295 eV calculated with time-dependent density functional theory (TD-DFT). As a result, 1a and 1b are expected to be potential thermally activated delayed fluorescence (TADF) materials. The electrochemical properties of the four compounds in dichloromethane solution were determined through cyclic voltammetry using TBAPF6 as supporting electrolyte and ferrocene as internal standard. The HOMO energy levels of 1a, 1b, 2a and 2b are estimated to be -5.369, -5.111, -5.412 and -5.075 eV, respectively. The thermal properties of the four compounds were investigated by thermal gravimetric analysis under nitrogen atmosphere at a heating rate of 10 ℃·min-1 and all compounds show good thermal stability with decomposition temperatures above 420 ℃.

Key words: blue light, thermally activated delayed fluorescence (TADF), phenothiazine, energy gap between thelowest singlet state and thelowest triplet state, photophysical properties, time-dependent density functional theory (TD-DFT)