Extending the luminescence lifetime of ruthenium(II) poly(pyridine) complexes in solution at ambient temperature
Extending the luminescence lifetime of ruthenium(II) poly(pyridine) complexes in solution at ambient temperature
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DOI：
10.1039/b300618m
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发表时间：
2003-01-01
影响因子：
4
通讯作者：
Ziessel, R
中科院分区：
文献类型：
--
作者：
Harriman, A;Khatyr, A;Ziessel, R
合成了一组钌(II)聚(吡啶)配合物，其中中心二乙炔化芘部分将2,2'-联吡啶和2,2':6',2"-三联吡啶末端分开。仅具有与金属阳离子配位的2,2'-联吡啶配体的单核配合物和相应的双核配合物在在室温下的脱氧乙腈溶液中，两个发射带在 0-60°C 的温度范围内似乎处于热平衡状态，但在 77 K 的冷冻玻璃中只能看到一个发射物质。在相同的实验条件下，磷光寿命明显长于母体配合物，但与大多数其他金属配合物-芘二元组不同，发光产率对痕量分子氧的存在极其敏感。具有两个钌(II)三(2,2'-联吡啶)基末端的化合物表现出类似的行为，考虑到所有测量的光物理和电化学性质，得出的结论是，三重态流形具有位于金属配合物上的金属-配体电荷转移态，与涉及芘和配位聚(吡啶)基团的分子内电荷转移态处于平衡状态。在一定温度下，仅观察到金属到配体的电荷转移三重态。
A set of ruthenium(II) poly(pyridine) complexes has been synthesized in which a central diethynylated pyrene moiety separates the 2,2'-bipyridine- and 2,2': 6',2"-terpyridine-based terminals. The mononuclear complex, having only the 2,2'-bipyridine ligand coordinated with the metal cation, and the corresponding binuclear complex show remarkably similar luminescence properties in deoxygenated acetonitrile solution at room temperature. Two emission bands are evident in the spectrum. These bands appear to be in thermal equilibrium over the temperature range 0-60degreesC but only a single emitting species is seen in a frozen glass at 77 K. The phosphorescence lifetimes are significantly longer than those associated with the parent complexes under the same experimental conditions but, unlike most other metal complex-pyrene dyads, the luminescence yield is extremely sensitive to the presence of trace amounts of molecular oxygen. The analogous compound having two ruthenium(II) tris(2,2'-bipyridine)-based terminals shows comparable behaviour. Allowing for all of the measured photophysical and electrochemical properties, it is concluded that the triplet manifold has the metal-to-ligand, charge-transfer state localised on the metal complex in equilibrium with an intramolecular charge-transfer state involving the pyrene and a coordinated poly( pyridine) group. The latter state lies at lower energy in a polar solvent and controls the photophysics. At low temperature, only the metal-to-ligand, charge-transfer triplet is observed.