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Sun ZZ, Zhu N, Pan X, Wang G, Li ZF, Xin XL, Han HL, Feng YB, Jin QH, Yang YP, Yang W. A new application of terahertz time-domain absorption spectra in luminescent complexes: characterization of the C-Hπ weak interactions in Cu(I) complexes. Dalton Trans 2021; 50:10214-10224. [PMID: 34232237 DOI: 10.1039/d1dt01023a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Six Cu(i) complexes, [Cu(2,3-f)(bdppmapy)]BF4 (1), [Cu(2,3-f)(bdppmapy)]ClO4 (2), [Cu(2,3-f)(bdppmapy)]CF3SO3 (3), [Cu(imidazo[4,5-f])(bdppmapy)]BF4 (4), [Cu(imidazo[4,5-f])(bdppmapy)]ClO4 (5), and [Cu(imidazo[4,5-f])(bdppmapy)]CF3SO3·MeOH (6·MeOH) (bdppmapy = N,N-bis[(diphenylphosphino)methyl]-2-pyridinamine, 2,3-f = pyrazine[2,3-f][1,10]-phenanthroline, and imidazo[4,5-f] = 1H-imidazo[4,5-f][1,10]-phenanthroline), have been synthesized to explore the effects of counteranions on their crystal structures, photophysical properties, and terahertz (THz) spectra. Time-dependent density functional theory (TD-DFT) shows that the luminescence performance of these complexes is attributed to the metal-to-ligand charge transfer (MLCT) in combination with ligand-to-ligand charge transfer (LLCT). In complexes 1-3, the characteristic peak at 1.4 THz is mainly related to the C-Hπ interaction formed by the H atom on the 4#/5# position of 2,3-f and the benzene ring from the bdppmapy on the adjacent asymmetric unit. The common C-Hπ interaction enhances the rigidity of the structure and has non-negligible influence on the photoluminescence quantum yields (PLQYs): the stronger the C-Hπ interaction is, the higher the quantum yield (QY) is. In complexes 4-6, similar absorption peaks (1.10-1.30 THz) are mainly related to the C-Hπ interactions, and strong absorption peaks (1.50-1.90 THz) are affected by the typical hydrogen bonds N-HF/O and O-HO. These results show that some weak interactions can be characterized by THz time-domain spectroscopy (THz-TDS). So, the THz spectroscopy method would make it possible to tune some of the weak interactions in complex structures to regulate the luminescence of materials.
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Affiliation(s)
- Zhen-Zhou Sun
- Department of Chemistry, Capital Normal University, Beijing 100048, China.
| | - Ning Zhu
- Department of Chemistry, Capital Normal University, Beijing 100048, China.
| | - Xun Pan
- Department of Chemistry, Capital Normal University, Beijing 100048, China.
| | - Guo Wang
- Department of Chemistry, Capital Normal University, Beijing 100048, China.
| | - Zhong-Feng Li
- Department of Chemistry, Capital Normal University, Beijing 100048, China.
| | - Xiu-Lan Xin
- School of Light Industry, Beijing Technology and Business University, Beijing 100048, China
| | - Hong-Liang Han
- Department of Chemistry, Capital Normal University, Beijing 100048, China.
| | - Yue-Bing Feng
- School of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Qiong-Hua Jin
- Department of Chemistry, Capital Normal University, Beijing 100048, China. and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Yu-Ping Yang
- School of Science, Minzu University of China, Beijing 100081, China
| | - Wei Yang
- Faculty of Food Science and Technology, Suzhou Polytechnical Institute of Agriculture, Suzhou 215008, P. R. China.
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