engleski

Anion recognition through hydrogen bonding by adamantane-dipyrromethane receptors

Adamantane-dipyrromethane (AdD) receptors [di(pyrrole-2-yl)methyladamantane (1), 2, 2-di(pyrrole-2-yl)adamantane (2), 1, 3-bis[di(pyrrole-2-yl)methyl]adamantane (3), 2, 2, 6, 6-tetra(pyrrole-2-yl)adamantane (4)] form complexes with F-, Cl-, Br-, AcO-, NO3-, HSO4-, and H2PO4-. The association constants of the complexes were determined by 1H NMR titrations, whereas the geometries of complexes 1•F- (2:1), 2•F- (2:1), 2•Cl- (2:1), 2•AcO- (2:1), and 4•F- (1:1) were determined by X-ray structural analysis. The most stable complexes are of 2:1 stoichiometry with F- and AcO-. The stability constants are in accordance with the anion basicity and the ability of AdD receptors to place the hydrogen bonding donor groups in a tetrahedral fashion around anions. The binding energies of the complexes between receptors 1-4 and F- anion are calculated using quantum chemical methods. The calculated results show that the solvent polarity is important for the complexation of fluoride ion with AdD receptors 1-4.

anion receptors ; pyrrole ; DFT calculations

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