Adsorption of metformin on graphitic carbon nitride functionalized with metals of group 1–3 (Li, Na, K, Be, Mg, Ca, B, Al, and Ga), DFT calculations

Abstract Metformin is one of the important anti-diabetic drugs. DFT calculations have been performed to study properties of adsorption of metformin onto [M/g-C3N4]+,+2,+3, where M: Li, Na, K, Be, Mg, Ca, B, Al, and Ga. Optimized structures of all systems were calculated using the ONIOM computational method. The results were used to calculate the absorption energy (Eads) with the PBE0-D3(BJ)/def2-TZVP method. The adsorption energy values for the most stable configurations are 19.1–131.6 kcal/mol. By adsorption of metformin on [M/g-C3N4]+,+2,+3 surfaces, the ionization potential values of [M/g-C3N4]+, M: Li, Na and K are low, which means that the stability of M: Li, Na and K systems are higher than the other systems (groups 2 and 3). The [M/g-C3N4]+ complexes have been seen as interesting adsorbents of metformin molecule.