Investigation on the Recognition of a Novel Multi-imidazole Cyclophane for a Series of Amino Acid Methyl Esters by Employing Density Functional Theory Method

It is rare to find a theoretical document involving the recognition of imidazole cyclophane for amino acid methyl ester(XOM).The interaction between a newly synthesized multi-imidazole cyclophane and XOMs was investigated by employing Density Functional Theory(DFT) method coupling with a descriptor of MS-WHIM Scores.It is suggested by analyzing the NBO charge that negative charge is transferred from XOM to cyclophane in the process of forming complex.It is coincident with the result of perturbation theory energy analysis,which indicates that the strongest delocalized stabilization energy resulting from the orbital interaction from XOM ligand to cyclophane receptor is larger than that from cyclophane to XOM ligand.A two-variable model based on the interaction energy is developed so as to express the binding constant of complex.It is found that there exists a good correlation between the experimentally determined constants and the theoretically calculated ones.The work reported here can serve as a foundation for us to design and synthesize novel imidazole cyclophanes which may bind to amino acid methyl ester more tightly.