State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Fudan University, 220 Handan road, Shanghai, 200433 (P.R. China).
Chemistry. 2015 Nov 16;21(47):16975-81. doi: 10.1002/chem.201502387. Epub 2015 Oct 6.
By carefully selecting an existing synthetic strategy and suitable coordination subunits, constructing desired coordination geometries is no longer that difficult to accomplish. Herein, a new strategy to construct a series of unprecedented structures by using conjugated CpRh-based complex BN-OTf (Cp = η(5)-C5Me5) as the building block is proposed. DFT calculations revealed extensive delocalized π bonds in the subunit. With BN-OTf, rectangular macrocycles TN-bpy and TN-bpe were controllably synthesized. Single-crystal XRD studies confirmed one-dimensional stacking channels for the tetranuclear structure. Notably, the starting ligand imidazole-4,5-dicarboxylate was found to act not only as a tetradentate but also as a hexadentate ligand that can coordinate to further metal ions. Subsequently, [4 Rh+1 M] heterometallic complexes HMZ (M = Cu and Zn) were accessed by chelating borderline hard/soft Lewis acids. With TN-Linker or HMZ, two routes resulted in the [8 Rh+2 M] heterometallic cages HMC (M = Cu and Zn) with excellent crystallinity and stability. Surprisingly, when BN-OTf bonded to rhodium itself, triangular prisms TP-Linker were obtained with high solubility after being linked by bipyridine linkers. Both the X-ray structure and (1)H NMR spectrum confirmed the novel isomerization of the triangular structures. All of the compounds were obtained in high yields and were fully characterized by (1)H NMR spectroscopy, elemental analysis, IR spectroscopy, and in most cases single-crystal X-ray structure determination.
通过仔细选择现有的合成策略和合适的配位亚基，构建所需的配位几何形状已不再那么困难。在此，提出了一种使用基于共轭 CpRh 的配合物 BN-OTf（Cp=η(5)-C5Me5）作为构筑块来构建一系列前所未有的结构的新策略。DFT 计算表明亚基中存在广泛的离域π键。利用 BN-OTf，可控合成了矩形大环 TN-bpy 和 TN-bpe。单晶 XRD 研究证实了四核结构的一维堆积通道。值得注意的是，起始配体咪唑-4,5-二羧酸不仅可以作为四齿配体，还可以作为六齿配体，进一步配位金属离子。随后，通过螯合边界硬/软路易斯酸，得到了[4Rh+1M]杂金属配合物 HMZ（M=Cu 和 Zn）。利用 TN-Linker 或 HMZ，两种途径得到了具有优异结晶度和稳定性的[8Rh+2M]杂金属笼 HMC（M=Cu 和 Zn）。令人惊讶的是，当 BN-OTf 与铑本身键合时，通过联吡啶配体连接后，得到了高溶解性的三角棱柱 TP-Linker。X 射线结构和（1）H NMR 谱证实了三角结构的新型异构化。所有化合物均以高产率获得，并通过（1）H NMR 光谱、元素分析、IR 光谱以及在大多数情况下单晶 X 射线结构测定进行了充分表征。
