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.
Bazzicalupi
Carla
C
Department of Chemistry, Polo Scientifico, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
Bencini
Andrea
A
Bianchi
Antonio
A
Borri
Claudia
C
Danesi
Andrea
A
Garcia-España
Enrique
E
Giorgi
Claudia
C
Valtancoli
Barbara
B
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