To cleave or not-disulfide bond of cystine on nanocopper: a computational approach

The stability of disulfide bond in cystine on nanocopper (Cu9) was probed at B3LYP/LANL2DZ/6-311 + + G(d,p) level of theory by taking unconnected cystine and Cu9 as inputs for optimizing the geometries. It was observed that cystine got chemisorbed on Cu9 interacting majorly through its disulfide and carboxyl functional groups. The simulated Raman spectrum revealed the cleavage of disulfide linkage by the disappearance of the -S-S- stretching mode, in good agreement with the earlier reported experimental study. NBO (natural bond orbital) analysis revealed the donation of lone pairs of electrons from oxygen and sulfur to copper in the Cu9-cystine system. Additionally, the predictions from MK (Merz Kollman), ESP (electrostatic potential) charge, FMO (Frontier molecular orbital), and AIM (atoms in molecule) calculations corroborated the above-mentioned results.

Automated summary

This study investigated the stability of cystine on nanocopper and its interaction with the copper surface. The results revealed that cystine chemisorbed on nanocopper through its disulfide and carboxyl functional groups, and the simulated Raman spectrum confirmed the cleavage of the disulfide bond.