Theoretical investigations of functionalization of graphene and ZnO monolayers with mercaptopurine at aqueous media: A dispersion-corrected DFT calculations and molecular dynamic simulations

Abstract

This study presents a theoretical investigation of mercaptopurine adsorption on graphene and ZnO monolayer using first-principles simulations with dispersion-corrected density functional theory (DFT). Two different interaction orientations for interacting mercaptopurine with the surface were evaluated and the energetically most stable configuration was obtained with −1.412 eV. The ZnO surface adsorbs mercaptopurine stronger than graphene. The electronic structure analysis indicates that the adsorption of molecule reduces the band gap of both considered semiconductor substrates while their semiconducting property still remains unchanged. Furthermore, charge analyses based on the Hirshfeld method revealed that around 0.213 e was transferred from the ZnO substrate to the mercaptopurine molecule. Density functional tight binding based molecular dynamics (DFTB-MD) simulations show that mercaptopurine tends to be adsorbed on both monolayers while moving from the water aqueous media toward the surface at room temperature. The DFT-based atoms-in-molecules (AIM) analysis predicted that themercaptopurine-graphene interaction nature is typical for the noncovalent type π-π interactions while mercaptopurine chemisorbed on the ZnO surface by chemical bonding between N/S and Zn atoms. The present results provide atomic insights on the interaction properties of mercaptopurine drug with graphene and ZnO nanosheets and supply new manner and worth data to assist the experiments and potential applications in thebio and nanotechnology area.