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从铜 (II) 超氧化物化合物中释放的取决于激发波长的O2:激光闪光光解实验和理论研究
Claudio Saracini1, Dimitrios G Liakos, Jhon E Zapata Rivera
1Department of Chemistry, The Johns Hopkins University , Baltimore, Maryland 21218, United States.
Journal of the American Chemical Society
|January 17, 2014
概括
铜 (II) 超氧化物复合物的可见光照射在低温下直接产生氧气. 这种光生成产量取决于激发波长,然后是快速的氧气与铜的重组.
科学领域:
- 无机化学 无机化学 有机化学
- 摄影化学的使用.
- 协调化学 协调化学
背景情况:
- 铜超氧化物复合物是各种生物和化学过程中的中间体.
- 了解它们的反应性,特别是在光下,对于催化和生物无机化学至关重要.
- 之前的研究已经探索了铜-氧相互作用,但从合成复合物中直接光生成O2仍然是活跃的研究领域.
研究的目的:
- 为了研究分子氧 (O2) 从合成铜 (II) -超氧化物复合物的直接光生成.
- 为了确定O2释放的波长依赖性和量子产量.
- 阐明所涉及的兴奋状态属性和反应机制.
主要方法:
- 用可见光 (436 nm和683 nm) 照射铜 (II) -超氧化物复合物 (TMG3tren) Cu (II) O2)) (1) 和 (PV-TMPA) Cu (II) O2) (2) .
- 在2-甲基四基 (MeTHF) 溶剂中进行低温光谱研究.
- 使用热量计方法确定O2重新结合和解离的度障碍.
- 时间依赖密度函数理论 (TD-DFT) 计算用于机械洞察力.
主要成果:
- 在低温下观察到O2气体的直接光生成 (-1的-40至-70°C,2的-1的-125至-135°C).
- 氧气释放率取决于波长,在436nm观察到的量子产量高于683nm.
- 检测到与相应的铜 (I) 种 (TMG3tren) Cu (I) ]+ (3) 和 (PV-TMPA) Cu (I) ]+ (4) 的快速O2重组.
- 量化了O2重结合 (∼10kJ mol(-1)) 和O2解离 (45kJ mol(-1) 复合物1的内壁垒.
- TD-DFT研究支持了实验结果,证实了兴奋状态的离散性.
结论:
- 可见光照射可以直接诱导特定的铜II-超氧化物复合物的O2释放.
- 光生成过程是高效的,并表现出波长的依赖性,表明不同的激发状态路径.
- 这项研究为铜氧物种的光化学提供了宝贵的机械洞察力,这对理解生物氧激活和开发新的光催化系统很重要.
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