Allosteric manipulation of photoexcited state relaxation in (bpy)2RuII(binicotinic acid).
Allosteric manipulation of photoexcited state relaxation in (bpy)2RuII(binicotinic acid).
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DOI：
10.1021/ic000288t
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发表时间：
2000-10
影响因子：
4.6
通讯作者：
M. Perkovic
中科院分区：
文献类型：
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作者：
M. Perkovic
(bpy)2RuII(联烟酸)的发射光谱和发光寿命受溶液中重金属离子存在的影响。低至 1 µM Pb2+ 即可引起发射红移、发射量子产率增加以及室温寿命延长。在大量铅存在的情况下，4,4'-二羧基类似物中观察到较小的红移；然而，发射寿命和强度会降低。基态几何形状的 X 射线测定表明联烟酸的联吡啶环沿着 2,2' 键扭曲 19.3 度。通过分子力学和扩展休克尔计算对铅和二烟酸络合物之间的相互作用进行了建模。计算表明，与铅的相互作用使联烟酸配体的桥环系统变平，从而影响配体的 pi* 能级、Ru(II) 的 d 轨道能量以及取代联吡啶配体可用的振动模式。在联烟酸复合物中观察到的反能隙定律行为可以用铅和联烟酸复合物之间的变构相互作用来解释。
The emission spectrum and luminescent lifetime of (bpy)2RuII(binicotinic acid) is affected by the presence of heavy metal ions in solution. As little as 1 microM Pb2+ causes a red shift in emission, an increase in the emission quantum yield, and an increase in the room-temperature lifetime. A smaller red shift is observed in the 4,4'-dicarboxy analogue in the presence of large quantities of lead; however, the emission lifetime and intensity are diminished. An X-ray determination of the ground-state geometry shows that the bipyridine rings of the binicotinic acid are twisted along the 2,2' bond by 19.3 degrees. The interaction between lead and the binicotinic acid complex was modeled by molecular mechanics and extended Hückel calculations. The calculations show that interaction with lead flattens the bridged ring system of the binicotinic acid ligand, which affects the pi* energy levels of the ligand, the d-orbital energies of the Ru(II), and the vibrational modes available to the substituted bipyridine ligand. The inverse energy gap law behavior observed in the binicotinic acid complex is explained in terms of an allosteric interaction between lead and the binicotinic acid complex.