Liu Shiqi, Kondratuk Dmitry V, Rousseaux Sophie A L, Gil-Ramírez Guzmán, O'Sullivan Melanie C, Cremers Jonathan, Claridge Tim D W, Anderson Harry L
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, OX1 3TA (UK).
Angew Chem Int Ed Engl. 2015 Apr 27;54(18):5355-9. doi: 10.1002/anie.201412293. Epub 2015 Feb 12.
Small alterations to the structure of a star-shaped template totally change its mode of operation. The hexapyridyl template directs the conversion of a porphyrin dimer to the cyclic hexamer, but deleting one pyridine site changes the product to the cyclic decamer, while deleting two binding sites changes the product to the cyclic octamer. This surprising switch in selectivity is explained by the formation of 2:1 caterpillar track complexes, in which two template wheels bind inside the nanoring. Caterpillar track complexes can also be prepared by binding the hexapyridyl template inside the 8- and 10-porphyrin nanorings. NMR exchange spectroscopy (EXSY) experiments show that these complexes exhibit correlated motion, in which the conrotatory rotation of the two template wheels is coupled to rotation of the nanoring track. In the case of the 10-porphyrin system, the correlated motion can be locked by binding palladium(II) dichloride between the two templates.
对星形模板结构进行微小改变会完全改变其操作模式。六吡啶基模板引导卟啉二聚体转化为环状六聚体，但删除一个吡啶位点会使产物变为环状十聚体，而删除两个结合位点会使产物变为环状八聚体。这种选择性的惊人转变可通过形成2:1的毛毛虫轨道复合物来解释，其中两个模板轮在纳米环内部结合。毛毛虫轨道复合物也可以通过将六吡啶基模板结合在8卟啉和10卟啉纳米环内部来制备。核磁共振交换光谱（EXSY）实验表明，这些复合物表现出相关运动，其中两个模板轮的同向旋转与纳米环轨道的旋转相耦合。在10卟啉系统中，通过在两个模板之间结合二氯化钯（II），可以锁定相关运动。
