[摘要]：The interaction of the biol. relevant anions deriving from the six pyridinedicarboxylic acids (H2PDC) with two macrocyclic receptors (II) moiety, as well as with the aliph. analog [21]aneN7 (3) (III), was studied by means of spectroscopic methods (UV-vis, NMR) and potentiometric titrns. affording the stability consts. of the adducts formed. All three receptors form stable complexes with the substrates thanks to the formation of several salt bridges and hydrogen bond contacts, as obsd. in the crystal structure of the H8[3(2,6-PDC)4]譎2O?.5EtOH solid compd. Addnl. p-stacking interactions between the arom. moieties of substrates and receptors enhance the stability of complexes with 1 and 2. Compds. 1 and 2 show a marked selectivity toward 2,6-pyridinedicarboxylate anions. In particular, 1 is able to perform a very efficient recognition of these species in the presence of 2 and 3. Mol. modeling calcns. suggested that such recognition ability of 1 can be ascribed to a superior structural and electrostatic complementarity with the substrate compared to 2 and 3.
