Affinity of aziridinium ion towards different nucleophiles: A density functional study

We have analyzed the affinity of aziridinium ion intermediate towards different nucleophilic centers using conceptual density functional theory based reactivity descriptors. The aziridinium ion is an unstable species, generated during the alkylation of DNA by nitrogen mustard, a class of bis-alkylating anti-cancer drug. The intermediate reacts with different nucleophilic (predominately on N7 of guanine in DNA) centers present in the biomolecules. It is expected that the interaction energy of the species with different nucleophiles depends on reactivity descriptors. To observe the interactions in gas phase as well as in aqueous phase we have used density functional theory (DFT) at B3LYP level of theory employing three different basis sets. Same method of calculation was carried out to obtain the DFT based reactivity descriptors.