- Degenerate [2]rotaxanes with electrostatic barriers
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A synthetic approach to the preparation of [2]rotaxanes (1-5·6PF6) incorporating bispyridinium derivatives and two 1,5-dioxynaphthalene (DNP) units situated in the rod portions of their dumbbell components that are encircled by a single cyclobi
- Li, Hao,Zhao, Yan-Li,Fahrenbach, Albert C.,Kim, Soo-Young,Paxton, Walter F.,Stoddart, J. Fraser
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experimental part
p. 2240 - 2250
(2011/04/27)
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- Tetrathiafulvalene radical cation dimerization in a bistable tripodal [4]rotaxane
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The template-directed synthesis of a bistable tripodal [4]rotaxane, which has cyclobis(paraquat-p-phenylene) (CBPQT4+) as the π-electron-de-ficient rings, and tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene units as the pairs of π-electron-rich recognition sites located on all three legs of the tripodal dumbbell, is described. The chemical and electrochemical oxidation of the [4]rotaxane and its tripo dal dumbbell have allowed us to unravel an unprecedented TTF+ radical cation dimerization. In fact, two types of TTF dimers, namely, the radical cation dimer [TTF+]2 and the mixed-valence one [(TTF) 2]+, have been ob served at room temperature for the tripodal dumbbell, whereas, in the case of the [4]rotaxane, only the radical cation dimer [TTF+]2 is formed. This anomaly can be explained if it is accepted that most of the neutral TTF units in the [4]rotaxane are encircled by CBPQT4+ rings, which renders the formation of the mixed-valence dimer [(TTF)2]+ highly unfavorable.
- Aprahamian, Ivan,Olsen, John-Carl,Trabolsi, Ali,Stoddart, J. Fraser
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supporting information; experimental part
p. 3889 - 3895
(2009/06/27)
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