Interaction of β-Cyclodextrin Catalyst with p-Chlorobenzonitrile for the Synthesis of 5-Substituted 1H-tetrazoles in n,n-Dimethylformamide:a DFT Study

The synthesis of 5-substituted 1H-tetrazoles in n,n-dimethylformamide(DMF) with b-cyclodextrin(b-CD) as catalyst can get an excellent yield in short reaction time.The interaction of b-CD with p-chlorobenzonitrile plays an important role in this process.This paper studies the complex of b-CD with p-chlorobenzonitrile using density functional theory(DFT) method.The minimum energy structure is investigated in water,DMF and DMSO.Hydrogen bonds are researched on the basis of natural bonding orbital(NBO) analysis.The relative position between p-chlorobenzonitrile and b-CD in DMF is confirmed by 1H nuclear magnetic resonance(1H NMR).The data from 13 C and 15 N spectra indicate that more positive charges focus on the carbon atom of cyanogroup(C11) and more negative charges concentrate on the nitrogen atom of cyanogroup(N12) upon complexation.The results from frontier molecular orbitals and Mulliken charge reveal that β-CD catalyst improves the reactivity and electrophilicity of p-chlorobenzonitrile.Meanwhile,the functional group of p-chlorobenzonitrile is easier to be attacked by azide ions in the presence of β-CD as catalyst.