Synthesis and structural characterization of anion complexes with azacalix[2]dipyrrolylmethane: effect of anion charge on the conformation of the macrocycle
Azacalix[2]dipyrrolylmethane is flexible changing its 1,3-alternate conformation to the 1,2-alternate, partial cone or cone conformations with respect to the charge on the anion, as shown by a series of single crystal X-ray structures of inorganic mono- and dianionic complexes.