Positive heterotropic cooperativity for selective guest binding via electronic communications through a fused zinc porphyrin array
Positive heterotropic cooperativity for selective guest binding via electronic communications through a fused zinc porphyrin array
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DOI：
10.1021/ja052993c
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发表时间：
2005-09-28
影响因子：
15
通讯作者：
Aida, T
中科院分区：
文献类型：
--
作者：
Sato, H;Tashiro, K;Aida, T
与4，4‘-联吡啶和N，N，N’，N‘-四甲基己烷-1，6-二胺等二胺类化合物结合时，具有两个电子偶联位置的环状主机1表现出负的各向同性协作性和正的各向异性协作性，它们的三元混合物在合适的条件下优先与1⊃C60·bpy和1⊃C60·TMHDA形成包合物。在甲苯中，20℃下的光谱滴定曲线表明，C60与单二胺络合物1⊃bpy(2.8×10 5m-1)和1⊃TMHDA(1.5×10 5m-1)的结合常数(Kassoc)分别是无客体C60(3.3×10 4m-1)的8.5倍和4.5倍。另一方面，单C60Complex 1⊃C60对TMHDA的可达性是无客户1的6.1倍。在没有1，6-二胺的情况下，吸收光谱表明C60与二胺之间没有直接相互作用。
Upon binding with C60and diamines, such as 4,4‘-bipyridine (bpy) andN,N,N‘,N‘-tetramethylhexane-1,6-diamine (TMHDA), cyclic host1possessing two electronically coupled binding sites displays negative homotropic cooperativity and positive heterotropic cooperativity, and their ternary mixtures preferentially form inclusion complexes with hetero-guest pairs1⊃C60•bpy and1⊃C60•TMHDA under appropriate conditions. Spectroscopic titration profiles in toluene at 20 °C demonstrated that the association constants (Kassoc) of C60with monodiamine complexes1⊃bpy (2.8 × 105M-1) and1⊃TMHDA (1.5 × 105M-1) are 8.5 and 4.5 times greater than that of C60with guest-free1(3.3 × 104M-1), respectively. On the other hand, mono-C60complex1⊃C60was 6.1 times more accessible than guest-free1toward TMHDA. Absorption spectroscopy in the absence of1indicated no direct interaction between C60and diamines.