New host molecules “Dicavitand-Porphyrins” [H2C2P(syn,syn) (3), H2C2P(syn,anti) (4)] with small cavities on one or both sides of the porphyrin plane were synthesized from 5,10-bis(2,6-dihydroxyphenyl)-15,20-diphenylporphyrin and bis(chloromethyl)cavitand in 15 and 34% yield, respectively. Similarity of guest size selectivity of the host 4 in comparison with the reported “Cavitand-porphyrin” [H2CP(syn) (1)] suggests that these hosts have the same cavity size. The 1:1 and 1:2 association constants (K11 and K12) of the guest encapsulations into 3 were also obtained by 1H NMR titration and nonlinear least square fittings. The guest size dependences of K11 and K12 values of 3 show that the initial cavity prefers larger guests such as ethane, while the second one does not. The induced-fit type very small structural changes (estimated within 1 Å) upon first guest encapsulation of the host 3 affects the guest encapsulation of the other cavity through the covalent linkages.
新的宿主分子“Dicavitand-Porphyrins”[H2C2P(syn,syn) (3), H2C2P(syn,anti) (4)]由 5,10-bis( 2,6-二羟基苯基)-15,20-二苯基
卟啉和双(
氯甲基)空
配体的产率分别为15%和34%。主体 4 的客体尺寸选择性与报道的“Cavitand-
卟啉”[H2CP(syn) (1)] 的相似性表明这些主体具有相同的空腔尺寸。客体封装到3中的1:1和1:2缔合常数(K11和K12)也通过1H NMR滴定和非线性最小二乘拟合获得。 K11 和 K12 值 3 的客体尺寸依赖性表明,初始空腔更喜欢较大的客体,例如
乙烷,而第二个空腔则不然。主体 3 的第一个客体封装时,诱导配合型非常小的结构变化(估计在 1 Å 以内)通过共价键影响另一个空腔的客体封装。