在二氧化物和水结合中以基导向的反应性-[Pd(NHC) 2(η2-O2)
Taryn D Palluccio1, Xiaochen Cai2, Subhojit Majumdar2
1Department of Chemistry, Tufts University , 62 Talbot Avenue, Medford, Massachusetts 02155, United States.
这项研究揭示了一种新的过氧化物复合物,cis-[Pd(IPr) 2,这与氧气进一步反应,形成一种独特的bis-超氧化物复合物,trans-[Pd(IPr) 2. 这种复合物的反应性增加与影响氧结合的固体因素有关.
科学领域:
- 有机金属化学
- 协调化学
- 催化剂
背景情况:
- 复合物与N-异环碳素 (NHC) 在催化过程中至关重要.
- 了解复合物与氧的反应性对于开发新的催化过程和防止催化剂降解至关重要.
研究的目的:
- 研究复合物与分子氧 (O2) 的反应.
- 描述反应产物的结构和特性.
- 阐明影响这些复合物的反应性和稳定性的因素.
主要方法:
- -NHC复合物的合成和表征.
- 使用O2和H2的低温反应研究.
- 包括鱼磁力测量和EPR在内的光谱研究.
- 用X射线结晶学进行结构测定.
- 密度函数理论 (DFT) 计算用于机械洞察.
主要成果:
- 发现一个不稳定的过氧化物复合体,cis-[Pd(IPr) 2,以及其随后的反应形成一个 bis-超氧化物复合体,trans-[Pd(IPr) 2.
- 双超氧化物复合体表现出单基基态与可访问的三基态.
- cis-[Pd(IPr) 2(η2-O2) ]与水发生反应,产生了trans-[Pd(IPr) 2(OH) ].
- 与IMes相比,IPr连接体的反应性增加归因于连接体排斥的减少,导致O2结合的减弱.
结论:
- NHC连体的固体质量显著影响了氧复合物的反应性.
- 动力学因素在双超氧化物复合物的形成中起着至关重要的作用,即使在热力学上受到青.
- 这项研究提供了对氧物种反应途径和电子性质的全面了解.
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