Probing the electronic structure and Au-C bonding in AuC2 nH (n = 4-7) using photoelectron imaging spectroscopy and quantum chemical calculations

Changcai Han; Xiao-Gen Xiong; Jing Hong; Shuai-Ting Yan; Zejie Fei; Hongtao Liu; Changwu Dong

doi:10.1039/d1cp05057e

Probing the electronic structure and Au-C bonding in AuC_{2 n}H (n = 4-7) using photoelectron imaging spectroscopy and quantum chemical calculations

Phys Chem Chem Phys. 2022 Feb 23;24(8):5039-5047. doi: 10.1039/d1cp05057e.

Authors

Changcai Han^{1

2}, Xiao-Gen Xiong³, Jing Hong^{1

2}, Shuai-Ting Yan^{2

4}, Zejie Fei¹, Hongtao Liu¹, Changwu Dong¹

Affiliations

¹ Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China. dongchangwu@sinap.ac.cn.
² University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
³ Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China.
⁴ Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.

PMID: 35143596
DOI: 10.1039/d1cp05057e

Abstract

We report a combined experimental and theoretical study on the structures and chemical bonding of AuC_2nH (n = 4-7) using photoelectron imaging and quantum chemical calculations. All the ground states of anions and neutral AuC_2nH have a linear geometry. The electron affinities (EAs) are measured to be 2.063(5), 2.157(5), 2.220(5), and 2.267(5) eV for AuC_2nH, n = 4-7, respectively. The photoelectron imaging data of AuC₈H^- and AuC₁₀H^- reveal major vibrational progressions in the Au-C stretching modes. The ground state stretching frequencies of the titled neutral molecules are 226, 193, 177, and 128 cm^-1, respectively. By comparing the experimental β value and theoretical molecular orbital analysis, we confirm that the CAM-B3LYP method is more suitable for describing the properties of such unsaturated long chains organogold clusters. The experimental and CAM-B3LYP methods give a big picture of the trend in EAs of AuC_2nH. This shows that the EA value becomes larger with an increase in the carbon chain length, and it also shows a slow increment for larger n. The NRT analysis shows that the change of the Au-C bond order is not obvious as the number of carbon atoms increases, and the covalent character dominates the Au-C chemical bonds in these neutral species. The current study provides a wealth of electronic structure information about long-chain AuC_2nH^- (n = 4-7) and their corresponding neutral counterparts.