Polyfunctional recognition of pyridinedicarboxylate anions with macrocyclic polyamine receptors containing heteroaromatic groups.
The interaction of the biologically relevant anions deriving from the six pyridinedicarboxylic acids (H2PDC) with two macrocyclic receptors containing a pentamine chain and a bipyridine (1) or a phenanthroline (2) moiety, as well as with the aliphatic analogue [21]aneN7 (3), was studied by means of spectroscopic methods (UV-vis, NMR) and potentiometric titrations affording the stability constants 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 observed in the crystal structure of the H8[3(2,6-PDC)4] x H2O x 0.5 EtOH solid compound. Additional pi-stacking interactions between the aromatic moieties of substrates and receptors enhance the stability of complexes with 1 and 2. Compounds 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. Molecular modeling calculations 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.
Department of Chemistry, Polo Scientifico, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
Carla
C
Bazzicalupi
Andrea
A
Bencini
Antonio
A
Bianchi
Claudia
C
Borri
Andrea
A
Danesi
Enrique
E
Garcia-España
Claudia
C
Giorgi
Barbara
B
Valtancoli
D000838:Anions; D001665:Binding Sites; D002264:Carboxylic Acids / Q000737:chemistry*; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D006860:Hydrogen Bonding; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D011073:Polyamines / Q000737:chemistry*; D011199:Potentiometry; D011725:Pyridines / Q000737:chemistry*; D013057:Spectrum Analysis; D055672:Static Electricity
D000838:Anions; D002264:Carboxylic Acids; D006841:Hydrocarbons, Aromatic; D047028:Macrocyclic Compounds; D011073:Polyamines; D011725:Pyridines