The cucurbit[n]uril family:: Prime components for self-sorting systems
The cucurbit[n]uril family:: Prime components for self-sorting systems
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DOI：
10.1021/ja055013x
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发表时间：
2005-11-16
影响因子：
15
通讯作者：
Isaacs, L
中科院分区：
文献类型：
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作者：
Liu, SM;Ruspic, C;Isaacs, L
我们使用H-1 NMR竞争实验，参考通过UV/维斯滴定测量的绝对结合常数，确定了宽范围的葫芦[n]脲（CB[n]）（其中n = 6-8）的主-客体复合物的K-a值。我们发现，较大的同系物CB [7]和CB[8]-分别保持大小，形状和官能团的选择性，代表CB的识别行为[6]。CB[7]的空腔被发现有效地容纳三甲基硅基。值得注意的是，CB[7]与金刚烷衍生物22-24相互作用的Ka值超过10（12）M-1！单独地对每个CB[n]观察到的高水平的选择性也对CB[n]家族集体观察到。也就是说，CB[6]、CB[7]和CB[8]对共同客体的选择性可以非常大。例如，相对于CB[7]，访客1、3和11分别以大于10（7）、10（6）和3000的因子偏好CB[8]。相反，客人23和24相对于CB[8]更喜欢CB[7]，分别是5100和990的系数。CB[n]家族单独和共同观察到的高水平选择性使其成为制备功能仿生自分选系统的主要组分。
We determined the values of K-a for a wide range of host-guest complexes of cucurbit[n]uril (CB[n]), where n = 6-8, using H-1 NMR competition experiments referenced to absolute binding constants measured by UV/vis titration. We find that the larger homologues-CB[7] and CB[8]-individually maintain the size, shape, and functional group selectivity that typifies the recognition behavior of CB[6]. The cavity of CB[7] is found to effectively host trimethylsilyl groups. Remarkably, the values of Ka for the interaction of CB[7] with adamantane derivatives 22-24 exceeds 10(12) M-1! The high levels of selectivity observed for each CB[n] individually is also observed for the CB[n] family collectively. That is, the selectivities of CB[6], CB[7], and CB[8] toward a common guest can be remarkably large. For example, guests 1, 3, and 11 prefer CB[8] relative to CB[7] by factors greater than 10(7), 10(6), and 3000, respectively. Conversely, guests 23 and 24 prefer CB[7] relative to CB[8] by factors greater than 5100 and 990, respectively. The high levels of selectivity observed individually and collectively for the CB[n] family renders them prime components for the preparation of functional biomimetic self-sorting systems.