一项实验和计算调查排除了在二复合体[Cp(CO) 2 Mn(N2 ) 中的N2 连接体上的直接核友性添加
Quentin Le Dé1, Amal Bouammali1, Christian Bijani1
1LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, 31077, Toulouse cedex 4, France.
Angewandte Chemie (International ed. in English)
|June 28, 2023
概括
(PhLi) 与二复合物反应时不是在N2联体上,而是在CO联体上,形成一个短暂的乙碳复合物. 这纠正了以前关于二联体活性的发现.
科学领域:
- 有机金属化学 有机金属化学
- 无机化学 无机化学 有机化学
- 反应机制 反应机制
背景情况:
- 过渡金属复合体中协调的二 (N2) 配体的反应性对于理解固定至关重要.
- 之前的研究表明,复合体中对协调的N2进行直接的核友性攻击.
- 澄清反应途径对于开发新的催化过程至关重要.
研究的目的:
- 重新检查二复合物[Cp(CO) 2Mn(N2) 和 (PhLi) 之间的反应.
- 为了阐明实际的反应路径和产品,纠正之前错误的分配.
- 调查直接对协调N2.2进行核友性攻击的可能性.
主要方法:
- 涉及复合物的合成和表征的实验研究.
- 谱分析和单晶X射线衍射用于结构确定.
- 密度函数理论 (DFT) 计算以建模反应机制和能量学.
主要成果:
- (PhLi) 与[Cp (CO) 2Mn (N2) ]的CO连接体发生反应,而不是N2连接体.
- 隔离和鉴定了一种中间的阳离子乙烯基碳酸二甲酸盐,[Cp(CO) ((N2) MnCOPh]Li,在-40°C以下是稳定的.
- 这种中间体在-20°C以上分解,失去N2形成酸盐复合物,[Cp(CO) 2MnPh]Li.
- 早些时候的报道错误地将这种酸复合物识别为一种二基化合物,误解了N2联体的行为.
结论:
- 甲对协调的二联体的直接核友性攻击不发生.
- 观察到的反应性涉及对碳酸连接体的攻击,导致一种乙碳酸中间体.
- 此前关于该系统中独特的N2连接体行为的主张被驳斥,对金属协调N2的直接核友攻击仍然没有得到证实.
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