title: Spectroscopic Identification of the Au-C Bond Formation upon Electroreduction of an Aryl Diazonium Salt on Gold.
abstract: Electroreduction of aryl diazonium salts on gold can produce organic films that are more robust than their analogous self-assembled monolayers formed from chemical adsorption of organic thiols on gold. However, whether the enhanced stability is due to the Au-C bond formation remains debated. In this work, we report the electroreduction of an aryl diazonium salt of 4,4'-disulfanediyldibenzenediazonium on gold forming a multilayer of Au-(Ar-S-S-Ar)n, which can be further degraded to a monolayer of Au-Ar-S-by electrochemical cleavage of the S-S moieties within the multilayer. By conducting an in situ surface-enhanced Raman spectroscopic study of both the multilayer formation/degradation and the monolayer reduction/oxidation processes, coupled to density functional theory calculations, we provide compelling evidence that an Au-C bond does form upon electroreduction of aryl diazonium salts on gold and that the enhanced stability of the electrografted organic films is due to the Au-C bond being intrinsically stronger than the Au-S bond for a given phenylthiolate compound by ca. 0.4 eV.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.|University of Chinese Academy of Sciences , Beijing 100039, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.
authors.forename: Lipo
authors.initials: L
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.|University of Chinese Academy of Sciences , Beijing 100039, China.
authors.forename: Yelong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemical Engineering, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: Xun
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Chemical Engineering, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: Ye
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.|College of Physics, Jilin University , Changchun, Jilin 130012, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.
authors.forename: Erkang
authors.initials: E
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, Jilin 130022, China.
authors.forename: Zhangquan
authors.initials: Z
authors.lastname: Peng