The adsorption selectivity of the functional groups of dithiothreitol and 1,4-butanedithiol 2,3-diamino on the Ge(1 0 0) surface

The adsorption selectivities between dithiothreitol (DTT) and 1,4-butanedithiol 2,3-diamino (BDD) were revealed through density functional theory (DFT) calculations. DFT calculations predict that DTT does not stably adsorb onto the Ge(1 0 0) surface because both hydroxyl and thiol group in DTT serve as similar nucleophilic groups, therefore they are not selective. However, BDD is predicted to adsorb stably onto the Ge(1 0 0) surface because the amine and thiol groups in BDD operate relatively different nucleophilic group, and it is selective. The adsorption energies of BDD onto the Ge(1 0 0) surface suggested that an S–H dissociated N2-H dissociation bonded structure is the most stable structure.