从电子转移到能量转移之间的pH驱动的机械切换[Ru(bpy) 3和铁素衍生物
Claire Drolen1, Eric Conklin1, Stephen J Hetterich1
1Department of Chemistry , Amherst College , Merrill Science Building , Amherst , Massachusetts 01002 , United States.
Journal of the American Chemical Society
|August 3, 2018
概括
质子可用性决定了三 (二) 激发状态如何与水中的铁衍生物相互作用. 火机制根据pH值在能量和电子转移之间切换, 显示复杂的失活路径.
科学领域:
- 摄影化学
- 超分子化学
- 电化学
背景情况:
- 三二) ([Ru(bpy) 3+) 激发状态在光化学中至关重要,通过能量或电子转移进行失活.
- 铁素衍生物是光物理研究中广泛使用的电子捐赠和火剂.
- 了解激发状态失活机制是设计高效光化学系统的关键.
研究的目的:
- 调查质子可用性对水溶液中的铁衍生物对[Ru(bpy) 3+激发状态失活路径的影响.
- 阐明火的机制,并确定调节速率常数的因素.
- 探索pH控制的能量和电子转移过程的潜力.
主要方法:
- 斯特恩-沃尔默灭分析以确定灭速率常数.
- 暂时的吸收光谱检测激发状态的动态.
- 功能化铁衍生物 (铁胺和铁三甲) 的合成和表征.
主要成果:
- 与铁三甲 (Fc-mam) 相比,铁二甲 (Fc-am) 的灭速率常数是依赖于pH的.
- 暂时吸收光谱显示了Fc-am的火机制中的pH依赖开关.
- 在低pH (质子化Fc-am) 时,能量转移占主导地位;在高pH (质子化Fc-am) 时,电子转移变得普遍.
- 观察到的机械转换不能用简单的驱动力论据来解释.
结论:
- 铁衍生物中可转移质子的存在或不存在显著调节了[Ru(bpy) 3+的激发状态火率.
- 溶液pH可以通过特定的铁衍生物可控地切换[Ru(bpy) 3+的失活机制 (能量与电子转移).
- 除了热力学驱动力之外的因素在这些双分子相互作用中起着决定激发状态停活路径的关键作用.
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