An ONIOM investigation on anion recognition of alkali-metal complexes with diurea calix[4]arene receptor
The ONIOM(B3LYP/6-31G(d):AM1) optimized structures of complexes of diurea calix[4]arene receptor (L) with alkali metals Li+, Na+ and K+ and their complexes with halide ions F-, Cl-, Br-, oxygen-containing anions HCO (3) (-) , HSO (4) (-) and CH3COO- ions were obtained. Binding energies and thermodynamic properties of complex receptors LiL (+), NaL (+) and KL (+) with these anions were determined. The binding stabilities according to binding energies of LiL (+), NaL (+) and KL (+) associated with anions computed either at the ZPVE-corrected ONIOM(B3LYP/6-31G(d):AM1) or BSSE-corrected B3LYP/6-31 + G(d,p)//ONIOM(B3LYP/6-31G(d):AM1) are in the same order: F- >> CH3COO- a parts per thousand HCO (3) (-) > Br- a parts per thousand HSO (4) (-) a parts per thousand Cl-. All the receptors LiL (+), NaL (+) and KL (+) were found to be selective toward fluoride ion.
alkali metal halide oxygen-containing anion binding energy diurea calix[4] arene oniom approach