Theoretical Study Of The Identification And Separation Of Serine Enantiomers On Metal Surfaces

All the amino acids in nature,except glycine,are chiral molecules.The vast majority of drugs are composed of chiral molecules,but left and right chiral molecules in the living body have different physiological effects.So it is vital important to distinguish and separate of chiral materials accurately for the field of chiral materials research,medicine synthesis and other fields.In this paper,serine enantiomers are selected as the models of study.By using the first-principles density functional theory(DFT),we simulate and calculate the adsorption structures and adsorption energies of serine enantiomers in the(531)surfaces of pure metal and alloyed metal,and take the type of substrate,temperature,and coverage into consider to study the serine enantiomers adsorption energy and adsorption energy differences,this paper includes three parts:(1)This paper systematically studied the adsorption behaviors of serine enantiomers on the surface of pure metal Cu,Ag,Au and Pd(531)under the low coverage,the results show that the adsorption strength and separation ability of serine enantiomers on Cu are better than Ag,Au and Pd,and the biggest adsorption energy difference of left and right serine enantiomers is 0.39 eV.In addition,the adsorption configurations of left and right serine enantiomers are different,and the simulated scanning tunneling micrographs have different growth directions.The results demonstrate that the separation ability of serine enantiomers on different pure metal surfaces depends on the magnitude of the total conformational strain of the molecules and the substrates.By characterizing the conformational strain with deformation energy,we find that the greater total conformational strain of the molecule and the substrate,the greater adsorption difference in the left and right serine enantiomer.(2)To obtain a better metal surface of separation serine enantiomers,and then we alloy Cu surface,which has the best separation ability of serine enantiomers,with other metal atoms.The results show that when Au is doped on Cu surface,the distance between the bonding substrate atoms increases and the adsorption energy difference of serine enantiomers becomes smaller.When Ni is doped on the Cu surface,the distance between the bonding atoms becomes smaller,and the larger the doping concentration,the smaller the substrate distance,the greater the adsorption energy difference of the serine enantiomers.(3)Under high coverage,we find that serine enantiomers form self-assembly on metal surfaces,the results show that the adsorption energy of serine enantiomers on Cu(531)is very small,but serine enantiomers on the two layers Ni-decorated Cu(531)surface has the biggest adsorption energy difference,and the separation ability is the best.In addition,the adsorption energy difference and the separation ability gradually increases with the increasing tempurature.