Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence
Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence
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DOI：
10.1021/jacs.1c03806
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发表时间：
2021-08-11
影响因子：
15
通讯作者：
Agapie, Theodor
中科院分区：
文献类型：
--
作者：
Bailey, Gwendolyn A.;Buss, Joshua A.;Agapie, Theodor
含金属-碳三键的开壳化合物，如碳化物和碳炔，在C-1氧合物的还原性阳离子化反应中作为可能的中间体具有重要的意义。尽管报道了大量的闭壳碳化物，但开壳碳化物变体非常有限，而且开壳碳化物尚未被报道。本文报道了第一端不同氧化还原态的开壳碳化物配合物[K][1]和[1][BAr4F] (1 = P2Mo（C:)(CO), P2 = terphenyl diphospine配体）以及一系列相关的开壳碳化物配合物的合成。通过单晶x射线衍射、核磁共振、EPR和红外光谱对配合物进行了表征，同时通过EPR研究和DFT计算对电子结构进行了探测，以评估自旋离域。在d(1)配合物中，自旋主要定位在金属上（类似于55-77% Mo d(xy)），离域在三键碳上类似于0.05-0.09 e（-）。在还原碳化物[K][1]中，直接的金属-芳烃相互作用使辅助配体还原，导致末端碳化物上的自由基特征被还原(
Open-shell compounds bearing metal-carbon triple bonds, such as carbides and carbynes, are of significant interest as plausible intermediates in the reductive catenation of C-1 oxygenates. Despite the abundance of closed-shell carbynes reported, open-shell variants are very limited, and an open-shell carbide has yet to be reported. Herein, we report the synthesis of the first terminal, open-shell carbide complexes, [K][1] and [1][BAr4F] (1 = P2Mo( C:)(CO), P2 = a terphenyl diphosphine ligand), which differ by two redox states, as well as a series of related open-shell carbyne complexes. The complexes are characterized by single-crystal X-ray diffraction and NMR, EPR, and IR spectroscopies, while the electronic structures are probed by EPR studies and DFT calculations to assess spin delocalization. In the d(1) complexes, the spin is primarily localized on the metal (similar to 55-77% Mo d(xy)) with delocalization on the triply bonded carbon of similar to 0.05-0.09 e(-). In the reduced carbide [K][1], a direct metal-arene interaction enables ancillary ligand reduction, resulting in reduced radical character on the terminal carbide (