解辅助连接体捐赠对氧化作用对金属化物反应活性的位置
Samyadeb Mahato1, Warren VandeVen1, Gregory A MacNeil1
1Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada tim_storr@sfu.ca.
Chemical science
|February 9, 2024
概括
氧化位置 (金属与连接体) 显著影响化的活性,而不是辅助连接体的电子捐赠. 这项研究阐明了氧化化合物中这些相互关联的效应.
科学领域:
- 无机化学 无机化学 有机化学
- 有机金属化学 有机金属化学
- 反应机制 反应机制
背景情况:
- 盐化物复合物是多用途的催化剂.
- 了解影响其反应性的因素对于催化剂设计至关重要.
- 连接体电子和氧化状态之间的相互作用是复杂的.
研究的目的:
- 研究辅助连接体电子捐赠能力和氧化位点对氧化化化合物的电友反应性的相对影响.
- 调整salen连接体的电子特性,并观察其对反应性的影响.
- 为了区分连接物捐赠和氧化场所的影响.
主要方法:
- 一系列氧化Mn salen化物复合物的合成和特征化,使用不同类型的Para-phenolate替代剂.
- 电化学研究以确定氧化位置.
- 电子偏磁共振 (EPR) 光谱和UV-vs-NIR光谱检测电子结构.
- 密度函数理论 (DFT) 计算用于理论见解.
- 与三烯斯一起进行反应性研究,以形成酸胺添加物.
- 哈梅特分析,以将替代剂效应与反应速率相关联.
主要成果:
- 在较少的电子捐赠替代物 (R = CF3, H, tBu, OiPr) 的金属中心 ([Mn(VI) ]) 发生氧化.
- 对于更多的电子捐赠替代物 (R = NMe2, NEt2) 观察到联结基形成 ([Mn(V) ]+•).
- 随着联体的电子捐赠能力的增加,与联体的反应速率下降.
- 哈梅特图中的一个突破表明,氧化位置,而不仅仅是连接体捐赠,主导了反应性.
结论:
- 氧化位置 (金属与连接体) 对化物的电友反应性产生更大的影响,而不是辅助化体连接体的整体电子捐赠能力.
- 这项工作清楚地区分了连接体电子和氧化位点在确定反应结果中的微妙和相互关联的作用.
- 这些发现有助于更深入地了解化系统中的反应性,并为未来的催化剂设计提供信息.
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