A new insight of structures, bonding and electronic properties for 6-mercaptopurine and Ag8 clusters configurations: a theoretical perspective

Abstract

Background Many reports have also shown that the silver nanoparticles can effectively increase the anticancer drug activity and intensely enhance the drug curative effect. The adsorption of 6MP on nanomaterials has received a lot of attentions because of the drug coordination to its chemotherapeutic activity. The geometrical structures, chemical bonds, molecular orbital properties as well as density of states for the configurations were analyzed to deeply understand the interactions between the 6MP and Ag 8 clusters for high effect anticancer drug production. Results In this work, the density functional theory B3LYP has been used to investigate the structures and properties of the configurations between 6-mercaptopurine (6MP) and Ag 8 clusters using 6-311++G** level as well as an effective pseudo potential LANL2DZ. The geometries of ten configurations were optimized with full freedom. The geometrical structures, chemical bonds, molecular orbital properties as well as density of states for partial configurations were analyzed based on the density functional calculations. Polarizable continuum solvent model (PCM) in self-consistent reaction field (SCRF) were used for the aqueous calculations. The influences of temperature and pressure on the stability of the predominant configurations in the gas phase were further considered using standard statistical thermodynamic methods from 50 to 500 K and at 1 bar or 100 bar. Conclusion The result shows that there are ten stable configurations in the gas phase and there is a strong chemical bond between a Ag and S atom in the most stable configuration. The analysis of density of states also shows that the Ag–S chemical bond in the most stable configuration has been formed. Moreover, the results show that the temperature and the pressure will significantly influence the stability of the configurations in the gas phase. Additionally, when the solvent effect was considered, we found that there are only seven stable configurations and the solvent have different effect on various configurations. Electronic supplementary material The online version of this article (10.1186/s13065-019-0573-z) contains supplementary material, which is available to authorized users.

Adsorption/Desorption Behaviors and SERS Chemical Enhancement of 6-Mercaptopurine on a Nanostructured Gold Surface: The Au20 Cluster Model

“…The Au 20 tetrahedron is also well-known as an outstanding indicator in cluster science for its exceptional stability and peculiar 20-electron superatom shell structure [62,63]. Regarding the molecular structure of a 6MP drug, out of several stable configurations [64,65], two planar tautomers-6MP-7 and 6MP-9, presented in Figure 2tend to dominate its ground state population with a large quantity in both the gas phase and aqueous environments, as reported in recent literature [48,64,66]. In a vacuum, 6MP-7 lies 3 kcal/mol above 6MP-9, but this energy difference is significantly reduced to~1 kcal/mol in a water solution (PBE/cc-pVTZ value).…”

“…Rashidpour et al [47] analyzed the adsorption of 6MP on an Au 10 surface and found that the conjugation is energetically preferred via the S and S-N sites of the drug molecule. Ren and co-workers [48] also investigated the structures, bonding features, and stability of the complexes of 6MP with an Ag 8 cluster by means of DFT (B3LYP) calculations. In a recent study [49] we elucidated the binding mechanism of both 6-mercaptopurine and 6-thioguanine to the Au 6 and Au 8 clusters.…”