Polycyclic complexes containing a bridgehead transition metal are interesting species because the transition metal is shared by all the rings simultaneously. In this study, we present a novel osmium–bridgehead system with three fused five-membered rings. This novel framework can be viewed as a 10-atom carbon chain coordinating to the osmium center. In sharp contrast to the nonplanar organic analogue, this unique metallacycle exhibits good planarity, which was unambiguously verified by means of X-ray diffraction. Interestingly, preliminary DFT calculations show that the aromaticity in the three 5MRs of these osmatricycles can be easily tuned by the ligand substitution. Finally, the broad UV/Vis absorption spectra of these novel polycyclic complexes were also reported.

中文翻译：

---

具有三个熔融五元环的金属环骨架的合成与表征

包含桥头过渡金属的多环配合物是有趣的物种，因为过渡金属同时被所有环共享。在这项研究中，我们提出了一个具有三个稠密五元环的新颖的–桥头系统。这种新颖的构架可以看作是与the中心配位的10原子碳链。与非平面有机类似物形成鲜明对比的是，这种独特的金属环化合物具有良好的平面性，这一点已通过X射线衍射进行了明确验证。有趣的是，初步的DFT计算表明，这些渗透环的三个5MR中的芳香性可以通过配体取代轻松地进行调节。最后，还报道了这些新颖的多环配合物的宽紫外/可见吸收光谱。