Structure, intramolecular flexibility, and complexation of aza crown ethers to anions H2PO4− and HSO4− in nonprotic solvents

Both the structure and intramolecular flexibility of a series of aza crown ethers were studied by experimental NMR and theoretical molecular modeling. The stoichiometries of complexation to the anions H2PO4− and HSO4− and resulting complex stabilities were determined by experimental NMR (1H, 31P) titration and, in addition, the structure and mobility changes of the aza crown ethers upon complexation were also examined.