Theoretical Studies on Structures and Spectroscopic Properties of Cyclometalated Gold(III) Complexes

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• 作者：Bao-Zhu Yang ; Xin Zhou ; Tao Liu ; Fu-Quan Bai ; Hong-Xing Zhang
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：August 20, 2009
• 年：2009
• 卷：113
• 期：33
• 页码：9396-9403
• 全文大小：254K
• 年卷期：v.113,no.33(August 20, 2009)
• ISSN：1520-5215

文摘

The electronic structures and spectroscopic properties of the four tridentate cyclometalated Au(III) complexes [Au(C)C≡CPh] (1), [Au(C)C≡CPh] (2), [Au(C)C≡CPh]⁺ (3), and [Au(N)C≡CPh]⁺ (4) [HCH = 2,6 -diphenylpyridine, CCH = 3-(2-pyridyl)biphenyl, CH = 6-phenyl-2,2′- bipyridine, CH = 1,3-di(2-pyridyl)benzene] were calculated to explore their spectroscopic nature. The geometry structures of 1−4 in the ground and excited states were optimized under the density functional theory (DFT) and the single-excitation configuration interaction (CIS) level, respectively. The absorption and emission spectra in CH₂Cl₂ solution were calculated by the time-dependent density functional theory (TD-DFT) with the PCM solvent model. As revealed from the calculations, with the variation of pyridyl in position and the number, the electron-accepting ability of pyridyl in 1−4 are different. With increasing the electron-accepting ability of pyridyl, the HOMO−LUMO energy gaps of 1−4 decrease, and the lowest-energy absorption bands and emission bands are red-shifted in the order 1 < 2 < 4 < 3. All of the lowest-energy absorptions are assigned as the LLCT character, and the solvent polarity has little impact on the absorption spectra. The 477 nm emission of 1 arises from the ³ILCT transition, whereas the 517 and 634 nm emission of 2 and 3, respectively, come from the ³LLCT and ³ILCT. In addition, the 577 nm emission of 4 is assigned as ³LLCT/³LMCT character.