物理化学学报 >> 2017, Vol. 33 >> Issue (7): 1390-1398.doi: 10.3866/PKU.WHXB201704111

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含TEMPO配合物的合成、表征、谱学性质及光猝灭机理

尹璐1,梁程2,陈可先3,赵琛烜1,姚加1,李浩然1,2,*()   

  1. 1 浙江大学化学系,浙大-新和成联合研发中心,杭州310027
    2 浙江大学化学工程与生物工程学院,杭州310027
    3 浙江工商大学食品与生物工程学院,杭州310018
  • 收稿日期:2017-01-11 发布日期:2017-05-31
  • 通讯作者: 李浩然 E-mail:lihr@zju.edu.cn
  • 基金资助:
    国家自然科学基金(21573196);国家自然科学基金(J1210042);浙江科技创新团队项目(2011R50007);国家高技术研究发展计划项目(863)(SS2015AA020601);中央高校基本科研业务费专项资金资助

Synthesis, Characterization, Spectroscopic Properties, and Luminescence Quenching Mechanism of a Pt(Ⅱ) Complex Decorated with a π-Conjugated TEMPO-Terpyridine Ligand System

Lu YIN1,Cheng LIANG2,Ke-Xian CHEN3,Chen-Xuan ZHAO1,Jia YAO1,Hao-Ran Li1,2,*()   

  1. 1 ZJU-NHU United R & D Center, Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China
    2 College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
    3 School of Food Science and Biotechnology, Zhejiang Gongshang University Hangzhou, Hangzhou 310018, P. R. China
  • Received:2017-01-11 Published:2017-05-31
  • Contact: Hao-Ran Li E-mail:lihr@zju.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21573196);The project was supported by the National Natural Science Foundation of China(J1210042);Program for Zhejiang Leading Team of S&T Innovation(2011R50007);National High Technology Research and Development Program of China (863)(SS2015AA020601);Fundamental Research Funds of the Central Universities, China

摘要:

通过由2,2,6,6-四甲基哌啶-氮-氧化物(TEMPO)自由基修饰的三联吡啶配体与二价金属铂盐反应,合成得到一种新型的金属配合物,[Pt(terpy-TEMPO)Cl]Cl·H2O·CH3OH(terpy指2,2':6',2"-三联吡啶)。此配合物由于TEMPO自由基的作用呈现高效率的光猝灭现象。X衍射单晶数据证实此配合物的分子结构信息。利用紫外、荧光及电子顺磁共振光谱等谱学手段探讨了该配合物的紫外吸收、发射及电子顺磁共振(EPR)光谱性质。[Pt(terpy-TEMPO)Cl]Cl·H2O·CH3OH的室温紫外吸收光谱表明,此配合物有两个典型的紫外吸收波段,强吸收段和次强吸收段,分别来源于配体到配体的跃迁(MLCT),金属到配体的跃迁(LLCT)。另外,[Pt(terpy-TEMPO)Cl]Cl·H2O·CH3OH的室温固体荧光光谱表明,TEMPO的单电子能有效地猝灭三联吡啶铂的荧光发射。我们对此猝灭机理进行了详细合理的阐述,并通过高斯09软件包对配合物的能隙和能带进行了量化计算,结果进一步证明配合物体系中的TEMPO单电子能极大的影响最高占有分子轨道(HOMO)与最低未占分子轨道(LUMO)之间的能级差,从理论上解释了三联吡啶铂配合物的光猝灭的光学性质与分子结构之间的关系。EPR结果表明,稳定自由基上接上金属配合物,不影响自由基A值和g值(A值指自由基超精细耦合常数,g值指自由基的g因子),但影响自由基转动、弛豫时间。

关键词: 三联吡啶铂配合物, 氮氧自由基, 合成, 光致发光, 电子顺磁共振光谱

Abstract:

A novel Pt(Ⅱ)-based metallointercalator terpyridine complex linked with a 2, 2, 6, 6-tetramethyl-1-piperidinyl N-oxide (TEMPO) derivative was prepared by a reaction between 4'-TEMPO-terpyridine (L) and a Pt(Ⅱ) salt. This complex presented unusual luminescence quenching owing to the effect of the stable nitroxide radical. The crystal structure of[Pt(terpy-TEMPO)Cl]Cl·H2O·CH3OH (terpy=2, 2':6', 2"-terpyridine) was elucidated by X-ray crystallography. Additionally, the effect of TEMPO on the photophysical properties of[Pt(terpy-TEMPO)Cl] Cl·H2O·CH3OH was investigated by UV-Vis, fluorescence emission, and electron paramagnetic resonance (EPR) spectroscopy. Data from the absorption and luminescence properties (298 K) of the[Pt(terpy-TEMPO)Cl]+ complex indicated the presence of two groups of typical bands:an intense band B with distinct vibronic structures (270-350 nm, ε>104 dm3·mol-1·cm-1) and a less intense band A (370-450 nm, ε~103 dm3·mol-1·cm-1). These two bands are generally assigned to ligand-to-ligand charge transfer (LLCT) and metal-to-ligand charge transfer (MLCT) excited states, respectively. Furthermore, efficient photoluminescent quenching behavior was observed in the emission spectra of this complex system. Quantum calculations of the molecular energy gaps and bands were performed by Gaussian 09 software. The calculated results verified that TEMPO greatly affects the energy gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital. Thus, the relationship between efficient photoquenching and molecular structure was theoretically interpreted. EPR results indicated that when TEMPO is attached to a macrocyclic terpyridine platinum complex, e.g., [Pt(terpy)Cl]+, the terpyridine platinum complex does not affect the hyperfine coupling constant (A value) and g factor (g values) but the rotation and relaxation times of the TEMPO radical.

Key words: Terpyridine Pt(Ⅱ) complex, Nitroxide radical, Synthesis, Photoluminescence, Electron paramagnetic resonance

MSC2000: 

  • O641