Interaction of Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, and Cr3+ metal ions on B12N12 fullerene-like cages: a theoretical study

Metal ions are the common pollutants in the aquatic environment, harmful to living organisms, non-biodegradable, and toxic even at low concentrations, thus, the present study aimed theoretically evaluate the potential for interaction of Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Pb 2+ , and Cr 3+ metal ions potentially toxic with B 12 N 12 nanocage. The location of the possible interaction sites was initially assessed by the Frontier Molecular Orbitals (FMOs), Molecular Electrostatic Potential, atomic charges NPA and the analysis allowed to predict the possible interaction sites. The results show that for ions with unpaired electrons in the valence shell, the interaction can occur on the boron atom or on the nitrogen atom. The interaction of the metal ions in the six-atom ring B–N–B–N–B–N is also possible, and site of interaction presented the longest bond lengths, > 3.2 Å. The calculations of the energies involved in the processes, binding energy ( E Bind ), Gibbs and enthalpy proved that the interaction of the metal cations with the B 12 N 12 nanocage is almost all spontaneously and follows the order: Zn 2+ > Ni 2+ > Cu 2+ > Cr 3+ > Co 2+ > Fe 2+ > Pb 2+ . The Quantum Theory of Atoms in Molecule (QTAIM) was used to determine the nature of the interaction between the metal ions and the nanocage showing that interactions are non-covalent or partially covalent. Finally, the results from NPA charge after the interaction showed that the direction of charge transfer is from metal ions to the nanocage. Graphic abstract