Long Carbon-Carbon Bonding beyond 2 Å in Tris(9-fluorenylidene)methane.
Long Carbon-Carbon Bonding beyond 2 Å in Tris(9-fluorenylidene)methane.
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DOI：
10.1021/jacs.1c07431
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发表时间：
2021-08
影响因子：
15
通讯作者：
T. Kubo;Yuki Suga;D. Hashizume;Hiroki Suzuki;T. Miyamoto;H. Okamoto;R. Kishi;M. Nakano
中科院分区：
文献类型：
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作者：
T. Kubo;Yuki Suga;D. Hashizume;Hiroki Suzuki;T. Miyamoto;H. Okamoto;R. Kishi;M. Nakano
我们报告了对长度超过 2.0 Å 的 C-C 键合的研究，这可以通过标题化合物中垂直面对的两个芴基环来实现。在 X 射线电子密度图上，观察到远处碳原子之间的小轨道重叠为小浓度的电子。该化合物的最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）分别源自重叠轨道的同相和异相相互作用，间隙为2.39 eV。固态 13C NMR 光谱显示长键碳在 82.9 ppm 处有尖峰，CASSCF(6,6) 计算表明存在小的双自由基特征。实验和理论分析揭示了长键碳对中存在足够的共价键相互作用。
We report on our investigation of C-C bonding longer than 2.0 Å, which can be realized by perpendicularly facing two fluorenyl rings in the title compound. A small orbital overlap between the distantly positioned carbon atoms is observed as a small concentration of electrons on the X-ray electron density map. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the compound originate from the in-phase and out-of-phase interactions of the overlapping orbitals, respectively, with a gap of 2.39 eV. Solid-state 13C NMR spectroscopy shows a sharp peak at 82.9 ppm for the long-bonded carbons, and a CASSCF(6,6) calculation indicates small diradical character. The experimental and theoretical analyses reveal sufficient covalent-bonding interaction in the long-bonded carbon pair.