Functionalized O6–Corona[6]arenes: Synthesis, Structure, and Fullerene Complexation Property

The synthesis, structure, and fullerene complexation property of novel and functionalized On–corona­[n]­arenes were reported. Based on the fragment coupling strategy, ester-containing On–corona­[n]­arenes (n = 6, 8) were obtained readily starting from 1,4-hydroquinone and diethyl 2,5-difluoroterephthalate. Reduction of esters with LiAlH4 produced almost quantitatively hydroxymethylated On–corona­[n]­arenes, which underwent etherification with MeI to afford methoxymethyl-substituted On–corona­[n]­arenes (n = 6, 8) in good yields. The macrocycles adopt unique corona-type conformation with a large cylindroid cavity. They are strong macrocyclic host molecules to form 1:1 complexes with fullerenes C60 and C70 in toluene with an associate constant up to (1.59 ± 0.04) × 105 M–1.本文报道了新型官能化冠型[n]芳烃（On–corona[n]arenes）的合成、结构及富勒烯络合性能。基于片段偶联策略，以1,4-氢醌（1,4-hydroquinone）和2,5-二氟对苯二甲酸二乙酯（diethyl 2,5-difluoroterephthalate）为起始原料，可便捷地得到含酯基的冠型[n]芳烃（n=6, 8）。采用氢化铝锂（LiAlH4）对酯基进行还原，可近乎定量地获得羟甲基化冠型[n]芳烃；该产物再与碘甲烷（MeI）发生醚化反应，以优异收率得到甲氧基甲基取代的冠型[n]芳烃（n=6, 8）。该类大环化合物呈现独特的冠状构象，拥有较大的长圆柱状空腔。其作为性能优异的大环主体分子，可在甲苯溶剂中与富勒烯C60和C70形成1:1型络合物，结合常数最高可达(1.59 ± 0.04) × 10^5 M^-1。