Contortions of encapsulated alkyl groups.
Contortions of encapsulated alkyl groups.
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DOI：
10.1039/b617548a
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发表时间：
2007-07
影响因子：
4.9
通讯作者：
J. Rebek
中科院分区：
文献类型：
--
作者：
J. Rebek
转子被认为是通过构象变化传递信息的早期分子装置。具体情况涉及联吡啶和联苯，其中联芳基键作为支点将施加的应力从一个位点传递到另一个位点。被封装的分子所遇到的新类型的分子应力被识别-包括弯曲，拉直，挤压，研磨和压缩。对于可逆形成的胶囊中的柔性分子，提出了识别的流体模型，该模型既不是锁和钥匙，也不是诱导拟合。相反，即使需要扭曲到更高能量的构象，客人也会呈现出最能填充可用空间的形状。对于封装的烷烃，吸引力和排斥力的微妙平衡存在时，一个客户分子的大小接近的可用空间it. The配合物的NMR和计算方法进行了分析，并提供了详细的地图的主机-客户界面在解决方案中。描述了一种包封的烷烃在压缩的、卷曲的构象和松弛的、延伸的构象之间的可逆转变。该系统是一种在酸和碱控制下的弹簧加载分子装置，为当前分子机器的转子提供了替代方案。
Rotors are recalled as early molecular devices that transmit information through changes in conformation. Specific cases involve bipyridyls and biphenyls in which the biaryl bond acts as a fulcrum to relay applied stresses from one site to another. New types of molecular stress encountered by encapsulated molecules are identified--including bending, straightening, squeezing, grinding and compression. For flexible molecules in reversibly formed capsules a fluid model of recognition is proposed that is neither lock-and-key nor induced fit. Instead, the guest assumes the shape that best fills the available space, even if contortions to higher energy conformations are required. For encapsulated alkanes, a delicate balance of attraction and repulsion exists when the size of a guest molecule approaches the space available to it. The complexes are analyzed by both NMR and computational methods and detailed maps of the host-guest interfaces in solution are provided. The reversible transition of an encapsulated alkane between a compressed, coiled conformation and a relaxed, extended one is described. The system is a spring-loaded molecular device under the control of acids and bases that offers an alternative to the rotors of current molecular machinery.