title: Chiral Au₂₅ nanospheres and nanorods: synthesis and insight into the origin of chirality.
abstract: Chirality in nanoparticles is an intriguing phenomenon. Herein, we have devised a well-defined gold nanoparticle system for investigating the origin of chirality in nanoparticles. We have designed chiral thiols (R- and S-isomers) and synthesized chiral gold nanoparticles composed of 25 gold atoms and 18 ligands, referred to as Au(25)(pet)(18), where pet represents chirally modified phenylethylthiolate -SCH(2)CH(CH(3))Ph at the 2-position. These optically active nanoparticles are close analogues of the optically nonactive phenylethylthioalte-capped Au(25)(pet)(18) nanoparticles, and the latter's crystal structure is known. On the basis of the atomic and electronic structures of these well-defined Au(25) nanoparticles, we have explicitly revealed that the ligands and surface gold atoms of Au(25)(pet)(18) play a critical role in effecting the circular dichroism responses from the nanoparticles. Similar effects are also observed in chiral Au(25) rods. The mixing of electronic states of ligands with those of surface gold atoms constitutes the fundamental origin of chirality in such nanoparticles.
authors.affiliation: Department of Chemistry, Anhui University, Hefei, Anhui 230039, People's Republic of China. zmz@ahu.edu.cn
authors.forename: Manzhou
authors.initials: M
authors.lastname: Zhu
authors.forename: Huifeng
authors.initials: H
authors.lastname: Qian
authors.forename: Xiangming
authors.initials: X
authors.lastname: Meng
authors.forename: Shenshen
authors.initials: S
authors.lastname: Jin
authors.forename: Zhikun
authors.initials: Z
authors.lastname: Wu
authors.forename: Rongchao
authors.initials: R
authors.lastname: Jin
mesh_terms: D002942:Circular Dichroism; D006046:Gold / Q000737:chemistry*; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry*; D008968:Molecular Conformation; D054118:Nanospheres / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013237:Stereoisomerism
chemical_list: D008024:Ligands; D006046:Gold