Fullerene Inclusion Based on Horning-Crown Macrocycles

Horning-crown macrocycles, 1(R = (CH2)2) and 2(R = (CH2)3) form inclusion complexes with C60 and C70 fullerenes which have been structurally authenticated using X-ray diffraction data. Macrocycle 1 affords a C60 complex as a toluene solvate with overall composition C60(1)2(tol)2, 3, whereas the larger macrocycle, 2, affords complexes with both C60 and C70 fullerenes, also as toluene solvates: C60(2)(tol)2, (4); C70(2)(tol)2, (5); and C70(2)2(tol)2, (6). The higher degree of flexibility of such macrocyles relative to classical calixarenes is noteworthy in forming fullerene complexes, with the smaller ring size of 1 favoring fullerene complexation toward the smaller C60 molecule. The supramolecular assemblies involve host−guest interactions as well as interaction of fullerenes in zigzag chains with interfullerene contacts close to the van der Waals limit.

霍宁冠大环（Horning-crown macrocycles）1（R=(CH₂)₂）与2（R=(CH₂)₃）可与C60、C70富勒烯形成包合复合物，其结构已通过X射线衍射（X-ray diffraction）数据得到确证。大环1可生成组成为C60(1)₂(tol)₂的甲苯溶剂化物复合物（即化合物3）；而尺寸更大的大环2则可分别与C60、C70富勒烯形成甲苯溶剂化物类复合物：C60(2)(tol)₂（化合物4）、C70(2)(tol)₂（化合物5）以及C70(2)₂(tol)₂（化合物6）。相较于经典杯芳烃（calixarenes），此类大环具有更高的柔性，这一特性在构建富勒烯复合物时尤为值得关注：1的环尺寸更小，更倾向于与尺寸更小的C60分子形成包合复合物。该超分子组装体（supramolecular assemblies）既存在主客体相互作用（host−guest interactions），同时富勒烯分子还会形成之字形链状排列，富勒烯间的接触距离接近范德华极限（van der Waals limit）。