title: Adsorption and properties of aromatic amino acids on single-walled carbon nanotubes.
abstract: We investigated the adsorption of three aromatic amino acids-phenylalanine, tyrosine, and tryptophan-on the sidewalls of a number of representative single-walled carbon nanotubes (SWNTs) using density-functional tight-binding calculations, complemented by an empirical dispersion correction. The armchair (n, n) SWNTs (n = 3-12) and zigzag (n, 0) SWNTs (n = 4-12) were thoroughly examined. We found that the most stable amino acid/SWNT complexes for different SWNTs have similar local structures, and that the distance between the amino acid and SWNT is about 3 Å. Owing to the π-π and H-π stacking interactions, the benzene and indole rings are not exactly parallel to the SWNTs but instead lie at a small angle. We also investigated the diameter and chirality dependences of binding energies and found that SWNT (5, 0) has an especially large binding energy that can be used for SWNT identification or selection.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China.
authors.forename: Cuihong
authors.initials: C
authors.lastname: Wang
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Ruiqin
authors.initials: R
authors.lastname: Zhang
authors.forename: Zijing
authors.initials: Z
authors.lastname: Lin
mesh_terms: D000327:Adsorption; D024322:Amino Acids, Aromatic / Q000737:chemistry*; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010649:Phenylalanine / Q000737:chemistry; D011789:Quantum Theory; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
chemical_list: D024322:Amino Acids, Aromatic; D037742:Nanotubes, Carbon; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan