A theoretical study on the interaction of [Al(H2O)6]3+ and [Mg(H2O)6]2+ cations with fullerene (C60), coronene and benzene π-systems

Density functional theory (DFT), Bader’s theory of atoms in molecules (AIM) and natural bond orbital (NBO) calculations have been used to understand the nature of the interaction between M(H2O)6n+ (M = Mg2+, Al3+) complexes and fullerene, coronene and benzene π-systems. The interaction energies were calculated for all the compounds and corrected for the basis set superposition error (BSSE). The results showed that the above π-systems have larger interaction energies with Al(H2O)63+ than Mg(H2O)62+. Also the AIM topological parameters for the bond critical points (BCPs) between the M(H2O)6n+ cations and the fullerene, coronene and benzene π-systems confirmed that {[Al(H2O)6]3+⋯fullerene} has a much stronger bonding interaction than the other systems. The calculated interaction energies correlate well with both the Wiberg bond indices and the global value of charge transfers from π-systems to cations evaluated through natural population analysis. The calculations suggest that the ionic potential of the central metal ion in the M(H2O)6n+ cation and the nature of π-system are two influential factors that affect the strength and the nature of the interaction.

Graphical abstractDensity functional theory (DFT), AIM and NBO calculations are used to understand the nature of the interaction between M(H2O)6n+ (M = Mg2+, Al3+) complexes with the π-systems of fullerene, coronene and benzene. The calculations suggest that the ionic potential of the central metal ion in the M(H2O)6n+ cation and the nature of π-system are two influential factors that affect the strength and the nature of the interaction.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The fullerene molecule is able to have a relatively strong interaction with suitable hydrated metal ions. ► The ionic potential of the hydrated metal ions has a significant effect on their interaction with π-systems. ► It is shown that [Al(H2O)6]3+ has a strong interaction with the fullerene π-system. ► The strength of the cation⋯π-system interactions can be evaluated through AIM and NBO calculations.