The effect of cation–π interactions on the stability and electronic properties of anticancer drug Altretamine: a theoretical study

The present work utilizes density functional theory (DFT) calculations to study the influence of cation–π interactions on the electronic properties of the complexes formed by Altretamine [2,4,6-tris(dimethylamino)-1,3,5-triazine], an anticancer drug, with mono- and divalent (Li + , Na + , K + , Be 2+ , Mg 2+ and Ca 2+ ) metal cations. The structures were optimized with the M06-2X method and the 6-311++G(d,p) basis set in the gas phase and in solution. The theory of `Atoms in Molecules' (AIM) was applied to study the nature of the interactions by calculating the electron density ρ( r ) and its Laplacian at the bond critical points. The charge-transfer process during complexation was evaluated using natural bond orbital (NBO) analysis. The results of DFT calculations demonstrate that the strongest/weakest interactions belong to Be 2+ /K + complexes. There are good correlations between the achieved densities and the amounts of charge transfer with the interaction energies. Finally, the stability and reactivity of the cation–π interactions can be determined by quantum chemical computation based on the molecular orbital (MO) theory.