Department of Chemistry and Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
J Am Chem Soc. 2017 Mar 1;139(8):2948-2951. doi: 10.1021/jacs.7b00515. Epub 2017 Feb 17.
Crystalline supramolecular frameworks consisting of charged molecules, held together by hydrogen bonds and Coulomb interactions, have attracted great interest because of their unusual structural, chemical, electronic, and magnetic properties. Herein, we report the preparation, structure, and magnetic properties of the triradical trianion of a shape-persistent chiral equilateral molecular triangle having three naphthalene-1,4:5,8-bis(dicarboximide)s ((+)-NDI-Δ). Single-crystal X-ray diffraction of its tris(cobaltocenium) salt ([(+)-NDI-Δ(CoCp)]) reveals accessible one-dimensional tubular cavities, and variable-temperature electron paramagnetic resonance spectroscopy shows that a dilute solution of [(+)-NDI-Δ(CoCp)] in an organic glass has a spin-frustrated doublet ground state and a thermally accessible quartet state. Furthermore, SQUID magnetometry from 5 to 300 K of solid [(+)-NDI-Δ(CoCp)] shows ferromagnetic ordering with a Curie temperature T = 20 K. The successful preparation of hybrid ionic materials comprising macrocyclic triradical trianions with spin-frustrated ground states and accessible 1D pores offers routes to new organic spintronic materials.
由带电分子通过氢键和库仑相互作用形成的晶体超分子框架由于其独特的结构、化学、电子和磁性质而引起了极大的兴趣。在此，我们报告了具有三个萘 1,4:5,8-双（二羧酸酰亚胺）（(+)-NDI-Δ）的形状保持手性等边分子三角形的三自由基三阴离子的制备、结构和磁性质。其三（钴叶立德）盐([(+)-NDI-Δ(CoCp)])的单晶 X 射线衍射揭示了可及的一维管状空腔，并且变温电子顺磁共振光谱表明，[(+)-NDI-Δ(CoCp)]在有机玻璃中的稀溶液具有自旋受挫的双重基态和热可及的四重态。此外，固态[(+)-NDI-Δ(CoCp)]的 SQUID 磁强计从 5 到 300 K 显示出具有居里温度 T = 20 K 的铁磁有序。成功制备了具有自旋受挫基态和可及的 1D 孔的大环三自由基三阴离子的混合离子材料为新型有机自旋电子材料开辟了途径。
