Dual Emissions from Ruthenium(II) Complexes Having 4-Arylethynyl-1,10- phenanthroline at Low Temperature
Dual Emissions from Ruthenium(II) Complexes Having 4-Arylethynyl-1,10- phenanthroline at Low Temperature
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具有 4-芳基乙炔基-1,10-菲咯啉的钌(II)配合物在低温下的双重发射
DOI：
10.1021/ic502843x
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发表时间：
2015
影响因子：
4.6
通讯作者：
N. Kitamura
中科院分区：
文献类型：
--
作者：
E. Sakuda;C. Matsumoto;Y. Ando;A. Ito;K. Mochida;A. Nakagawa;N. Kitamura
一个[Ru(phen)3]2+配合物（phen = 1,10-菲罗啉）在三个苯配体之一的4位上有一个芳基乙基（芳基（二烷基）），在碳酸丙烯酯（PC）中低温时表现出双重释放。来自最低能量激发三重态（T1）的较短发射寿命分量（τem(s)≈13 μs）几乎与温度（T= 77 ~ 320 K）无关，而较长的发射寿命分量（τem(l)），由于t2发射出现在PC的流-玻璃转变温度（Tg≈220 K）以下，在ofT= 77 ~ 220 K范围内几乎恒定在27 μs。配合物的τem(s)分量归属于具有较大配体中心（LC）激发态特征（T1(MLCT/LC)）的金属-配体电荷转移（MLCT）激发态的发射，而τem(l)分量来源于T2（MLCT）激发态。在T2（MLCT）激发态周围通过溶剂重组快速非辐射衰变，使得配合物的T2（MLCT）态在tgin PC以上变为非发射态。配合物的光物理性质也被证明是由苯基配体的4位上存在芳基乙基单位表征的。
A [Ru(phen)3]2+complex (phen = 1,10-phenanthroline) having an arylethynyl group at the 4-position of one of the three phen ligands (aryl: (dimesityl)borylduryl group =[RuBE]2+or duryl group =[RuDE]2+) showed dual emissions at low temperature in propylene carbonate (PC). The shorter emission lifetime components (τem(s) ≈ 13 μs) that originated from the lowest-energy excited triplet states (T1) of the complexes were almost independent of temperature (T= 77–320 K), while the longer emission lifetime components (τem(l)), as the T2emissions appeared below the fluid-to-glass transition temperature (Tg≈ 220 K) in PC, were almost constant at 27 μs in the range ofT= 77–220 K. The τem(s) components of the complexes were assigned to the emissions from the metal-to-ligand charge transfer (MLCT) excited states possessing relatively large ligand-centered (LC) excited-state characters (T1(MLCT/LC)), while the τem(l) components were shown to be originating from the T2(MLCT) excited states. The T2(MLCT) states of the complexes became nonemissive aboveTgin PC due to fast nonradiative decay through solvent reorganization around the T2(MLCT) excited states. The photophysical properties of the complexes were also shown to be characterized by the presence of the arylethynyl units at the 4-positions of the phen ligands.