|dc.description.abstract||Recently, Neri et al have introduced an efficient method to obtain endo-cavity
complexation and through-the-annulus threading of large calixarenes exploiting the
inducing effect of a weakly coordinating anion, tetrakis [3,5-bis (trifluoromethyl)
In this PhD thesis this approach has been used for the synthesis of rotaxanes,
which showed an unprecedented inversion of the wheel orientation.
Subsequently, it was extended to the synthesis of pseudorotaxane systems in
which two calixarene macrocycles are threaded by a bis(benzylalkylammonium) axle.
Because of the three-dimensional nonsymmetrical nature of the calixarene wheels, in
these instances three sequence stereoisomers could be obtained, which were termed as headto-
head (H,H), head-to-tail (H,T) and tail-to-tail (T,T).
Taking advantage of these systems, it was possible to obtain the stereoprogrammed
synthesis of the first examples of calixarene-based rotaxane architectures. The base/acid
treatment demonstrated that these systems act as molecular shuttles, which move on a
nanometer scale level. The directionality of the threading and the observed high stereoselection have
enabled the synthesis of directional calixarene-based catenane. All these aspects represent
interesting peculiar features of calixarene threading, which could be exploited for designing
molecular machines with new properties or functions||en_US