Feng Rui, Zhang Li, Ruan Huapeng, Zhao Yue, Tan Gengwen, Wang Xinping
State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China.
Angew Chem Int Ed Engl. 2019 Apr 23;58(18):6084-6088. doi: 10.1002/anie.201901177. Epub 2019 Mar 28.
The first main-group element radical based one-dimensional magnetic chain (1K) was realized by one-electron reduction of the pyridinyl functionalized borane 1 with elemental potassium in THF in the absence of 18-crown-6 (18-c-6). The electron spin density of (1K) mainly resides at the boron centers with a considerable contribution from central benzene and pyridine moieties. The spin centers exhibit an antiferromagnetic interaction as demonstrated by magnetic measurements and theoretical calculations. In contrast, the reduction in the presence of 18-c-6 afforded the separated radical anion salt 1K(Crown), in which the potassium cation was trapped by THF and 18-c-6 molecules. Further one-electron reduction of 1K(Crown) and (1K) led to the diamagnetic monomer and polymer, respectively.
在没有18-冠-6（18-c-6）的情况下，通过在四氢呋喃（THF）中用金属钾对吡啶基官能化硼烷1进行单电子还原，实现了首个基于主族元素自由基的一维磁链（1K）。（1K）的电子自旋密度主要位于硼中心，中心苯环和吡啶部分也有相当大的贡献。磁性测量和理论计算表明，自旋中心表现出反铁磁相互作用。相比之下，在18-c-6存在下进行还原得到了分离的自由基阴离子盐1K（冠醚），其中钾阳离子被THF和18-c-6分子捕获。对1K（冠醚）和（1K）进一步进行单电子还原分别得到了抗磁性单体和聚合物。
