Tris-ACE-α-cyclodextrin tripods: chemistry and metal coordination behaviour

The synthesis of C 3 -symmetrical tris- ACE -(6,6′-bis-heterocyclyl)-α-cyclodextrins via "one pot" Staudinger-Aza-Wittig (SAW) reaction is described. The spectroscopic properties of their metal coordination compounds were analysed. The spontaneous formation of metallosupramolecular helicates generate strong exciton coupling features enlighten much information on the nature, the geometries of the complexes and their absolute configuration. The selective cation binding induced conformational changes displayed by a new class of α-cyclodextrin-based receptor containing anchored 6,6′-bipyridyl units were exploited for cation recognition and helicate chiral assembly.