title: Theoretical and experimental studies of the interactions between Au2(-) and nucleobases.
abstract: Combined anion photoelectron spectroscopy and relativistic quantum chemical studies are conducted on nucleobase-Au2(-) cluster anions. The vertical detachment energies of uracil-Au2(-) (UAu2(-)), thymine-Au2(-) (TAu2(-)), cytosine-Au2(-) (CAu2(-)), adenine-Au2(-) (AAu2(-)), guanine-Au2(-) (GAu2(-)) are determined to be 2.71 ± 0.08 eV, 2.74 ± 0.08 eV, 2.67 ± 0.08 eV, 2.65 ± 0.08 eV and 2.73 ± 0.08 eV, respectively, based on the measured photoelectron spectra. Through computational geometry optimizations we have identified the lowest-energy structures of these nucleobase-Au2(-) cluster anions. The structures are further confirmed by comparison of theoretically calculated vertical and adiabatic electron detachment energies with experimental measurements. The results reveal that the Au2(-) anion remains as an intact unit and interacts with the nucleobases through N-HAu or C-HAu nonconventional hydrogen bonds. The nucleobase-Au2(-) cluster anions have relatively weak N-HAu hydrogen bonds and strong C-HAu hydrogen bonds compared to those of nucleobase-Au(-) anions.
authors.affiliation: Beijing National Laboratory for Molecular Sciences & State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. zhengwj@iccas.ac.cn.
authors.forename: Guo-Jin
authors.initials: GJ
authors.lastname: Cao
authors.forename: Hong-Guang
authors.initials: HG
authors.lastname: Xu
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Zheng
authors.forename: Jun
authors.initials: J
authors.lastname: Li
mesh_terms: D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: D006046:Gold; D004247:DNA