Nakagawa Atsushi, Sakuda Eri, Ito Akitaka, Kitamura Noboru
Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University , 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan.
Department of Chemistry, Graduate School of Science, Osaka City University , 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Inorg Chem. 2015 Nov 2;54(21):10287-95. doi: 10.1021/acs.inorgchem.5b01626. Epub 2015 Oct 22.
The electrochemical, spectroscopic, and phophysical properties of a series of Ru(II) complexes having a triarylborane-appended 2,2'-bipyridine (bpy) ligand(s) (RuBbpys: Ru(Bbpy)n(bpy)(3-n) (B1n) and Ru(B2bpy)n(bpy)(3-n) (B2n), B = (dimesityl)boryldurylethynyl group(s) at the 4- or 4,4'-position(s) in bpy, n = 1-3) are described. In the excited states of the complexes, the intramolecular charge transfer transitions between the π-orbital of the aryl group and the vacant p-orbital on the boron atom (π(aryl)-p(B) CT) synergistically interact with the metal-to-ligand charge transfer (MLCT) transitions. The molar absorption coefficient of the MLCT band (ε(MLCT)) of the complex increased with increasing n, and B23 showed extremely intense absorption with ε(MLCT) = 5.6 × 10(4) M(-1) cm(-1) at 488 nm. Furthermore, B23 showed the highest emission quantum yield (0.43) among those of the polypyridine Ru(II) complexes hitherto reported. As one of the interesting results, we report that the radiative rate constant of B2n shows the correlation with ε(MLCT). The effects of the synergistic MLCT/π(aryl)-p(B) CT interactions on the spectroscopic and photophysical characteristics of RuBbpys are discussed in detail.
描述了一系列具有三芳基硼烷连接的2,2'-联吡啶（bpy）配体的Ru（II）配合物（RuBbpys：Ru（Bbpy）n（bpy）（3-n）（B1n）和Ru（B2bpy）n（bpy）（3-n）（B2n），B = 在bpy的4-或4,4'-位置的（二甲基）硼基二茂铁乙炔基，n = 1-3）的电化学、光谱和光物理性质。在配合物的激发态中，芳基的π轨道与硼原子上的空p轨道之间的分子内电荷转移跃迁（π(aryl)-p(B) CT）与金属到配体的电荷转移（MLCT）跃迁协同相互作用。配合物的MLCT带的摩尔吸收系数（ε(MLCT)）随n的增加而增加，并且B23在488 nm处显示出极强的吸收，ε(MLCT) = 5.6 × 10(4) M(-1) cm(-1)。此外，B23在迄今报道的多吡啶Ru（II）配合物中显示出最高的发射量子产率（0.43）。作为有趣的结果之一，我们报道B2n的辐射速率常数与ε(MLCT)显示出相关性。详细讨论了协同MLCT/π(aryl)-p(B) CT相互作用对RuBbpys的光谱和光物理特性的影响。
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