Hou Xudong, Truong Nguyen Giang, Xu Tingting, Wei Haipeng, Seng Herng Tun, Huo Guifei, Wang Dingguan, Ding Jun, Wu Shaofei, Ungur Liviu, Wu Jishan
Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore.
Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore, Singapore.
Chemistry. 2022 Jun 1;28(31):e202200687. doi: 10.1002/chem.202200687. Epub 2022 Apr 13.
The incorporation of organic radicals into coordination polymers was considered as a promising strategy to promote metal-ligand exchange interactions, but there are only a very limited number of stable organic radical-based ligands that can serve well such a purpose. Herein, we report two new tris(2,4,6-trichlorophenyl)methyl (TTM) radical-based ligands L1 and L2 with two and three imidazole substituents, respectively. The imidazole unit serves as a coordination site and it can also stabilize the TTM radical by intramolecular donor-acceptor interaction. Coordination of L1 and L2 with cobalt(II) ions gave the corresponding one- (CoCP-1) and two-dimensional (CoCP-2) coordination polymers, the structures of which were confirmed by X-ray crystallographic analysis. Magnetic measurements and theoretical calculations suggest antiferromagnetic coupling between the paramagnetic cobalt(II) ions and the radical ligands. Our study provides a rational design for stable organic radical-based ligands and further demonstrated the feasibility of a metal-radical approach toward magnetic materials.
将有机自由基引入配位聚合物被认为是促进金属-配体交换相互作用的一种有前景的策略，但能够很好地实现这一目的的稳定的基于有机自由基的配体数量非常有限。在此，我们报道了两种新的基于三（2,4,6-三氯苯基）甲基（TTM）自由基的配体L1和L2，它们分别带有两个和三个咪唑取代基。咪唑单元作为一个配位位点，还可以通过分子内供体-受体相互作用稳定TTM自由基。L1和L2与钴（II）离子配位得到了相应的一维（CoCP-1）和二维（CoCP-2）配位聚合物，其结构通过X射线晶体学分析得以确证。磁性测量和理论计算表明顺磁性钴（II）离子与自由基配体之间存在反铁磁耦合。我们的研究为稳定的基于有机自由基的配体提供了合理设计，并进一步证明了金属-自由基方法用于磁性材料的可行性。
