Electronic and Structural Effects of Low-Hapticity Coordination of Arene Rings to Transition Metals
Electronic and Structural Effects of Low-Hapticity Coordination of Arene Rings to Transition Metals
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DOI：
10.1021/om5009583
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发表时间：
2014-11-24
期刊：
影响因子：
2.8
通讯作者：
Alvarez, Santiago
中科院分区：
文献类型：
--
作者：
Falceto, Andres;Carmona, Ernesto;Alvarez, Santiago
对芳烃与过渡金属在低亲和性(ETA(1)和ETA(2))模式下的配位进行了密度泛函计算和结构分析，包括对分子轨道的拟对称分析和引入的触觉图，该图显示了不同程度的中间亲和力。对[(PtL3)-L-II(C6H6)]模型络合物的计算表明，Eta(2)模式优先，而Eta(1)配位为低能跃迁跃迁。芳烃与金属配位的侧基的连接引入了几何约束，这导致了介于一到二之间的亲和力。ETA(1)芳烃配合物与苯正离子的比较表明，前者与金属的键合主要涉及芳烃的pi体系，对碳碳键的离域性质影响很小。这一行为与经常发现的CP的ETA(1)配位形成鲜明对比，该配位涉及Sigma键和环的完全脱芳构化。
A DFT computational study and a structural analysis of the coordination of arenes to transition metals in low -hapticity (eta(1) and eta(2)) modes have been developed, including a pseudosymmetry analysis of the molecular orbitals and the introduction of a hapticity map that makes evident the different degrees of intermediate hapticities. Calculations on [(PtL3)-L-II(C6H6)] model complexes reveal a preference for the eta(2) mode, while the eta(1) coordination is found to be a low-energy transition state for a haptotropic shift. The attachment of the arene to a side group that is coordinated to the metal introduces geometrical constraints, which result in hapticities intermediate between one and two. Comparison of the eta(1) arene complexes with benzonium cations shows that in the former case the bonding to the metal involves essentially the pi system of the arene, affecting only slightly the delocalized nature of the carboncarbon bonds. This behavior is in sharp contrast with the frequently found eta(1) coordination of Cp that involves sigma bonding and full dearomatization of the ring.