unit along the nanotube. In the solid state, the complex undergoes a further stage of self-assembly, thereby initiating extended oriented tubular structures. Crystallographic studies revealed that the positioning of the viologen dication in this asymmetric wheel is addressed by a complicated pattern of cooperative noncovalent intermolecular interactions that involve only one half of the host, whereas
Synthesis and Conformational Study of the First Triply Bridged Calix[6]azatubes
作者:Stéphane Le Gac、Xianshun Zeng、Olivia Reinaud、Ivan Jabin
DOI:10.1021/jo048137l
日期:2005.2.1
The first C3v- and D3h-symmetrical triply bridged calix[6]azatubes were prepared in good yields from the known 1,3,5-tris-methylated calix[6]arene through an efficient [1 + 1] macrocyclization reaction. A remarkably regioselective hexa ipso-nitration reaction led to a calix[6]azatube substituted at the wide rim in alternate position by tBu and nitro groups. A 1H NMR study showed that, whereas the parent