Designation and Exploration of Halide-Anion Recognition Based on Cooperative Noncovalent Interactions Including Hydrogen Bonds and Anion-π

A novel urea-based anion receptor with an electron-deficient-aromatic structural unit, N-p-nitrophenyl-N-(4-vinyl-2-five-fluoro-benzoic acid benzyl ester)-phenyl-urea (FUR), was designed to probe the potential for halide-anion recognition through cooperation of two distinct noncovalent interactions including hydrogen bond and anion-pi in this work. The nature of the recognition interactions between halide-anion and the designed receptor were theoretically investigated at the molecular level. The geometric features of the hydrogen bond and anion-pi of the FUR@X- (X = F, Cl, Br and I) systems were deeply investigated. The binding energies and thermodynamic information of the halide-anion recognitions show that the present designed FUR maybe selectively recognizes the anion F- based on the cooperation of N-H center dot center dot center dot F- hydrogen bond and anion-pi interactions both in vacuum and in solvents. IR and UV-visible spectrums of the free FUR and the FUR@F- have been simulated and discussed qualitatively, which may be helpful for further experimental investigation in future. Additionally, electronic properties and behaviors of the FUR@X- systems were discussed according to the calculations on the natural bond orbital (NBO) data, molecular electrostatic potential (MEP), and weak interactions regions.