Density functional theory studies on interaction between calix [4] bipyrrole and halide anions

A new class of calix [4] pyrrole analogue containing bipyrrole show a good affinity for halide anions. calix [4] bipyrrole and its complexes with the halide anions were investigated by density functional theory (B3LYP) at the 6-31G* and LANL2DZ level. It was shown that calix[4] bipyrrole and halide anions can form highly symmetric complexes by eight intermolecular hydrogen bonds. The interaction between calix [4] bipyrrole and halide anions decreased along the halide elemental period. The calculated results of frequency, charge distribution and front molecular orbital show that there are linear correlations between the BSSE correct binding energy and charge transference, N-H bond length, N-H stretch frequency shifts.