Photoelectron velocity-map imaging spectroscopic and theoretical study on the reactivity of the gold atom toward CH3SH, CH3OH, and H2O

Abstract

Photoelectron velocity-map imaging spectroscopy has been used to study the reaction of the anionic gold atom with the HR (R = SCH 3 , OCH 3 , OH) molecules. The solvated [Au· · ·HR] − and inserted [HAuR] − products have been experimentally observed for R = SCH 3 , whereas only solvated [Au· · ·HR] − products were found for R = OCH 3 and OH. This significant difference in the photoelectron spectra suggests the different reactivity of the Au − toward the CH 3 SH, CH 3 OH, and H 2 O molecules. Second order Møller-Plesset perturbation theory and coupled-cluster single double triple excitation calculations have been performed to aid the structural assignment of the spectra and to explore the reaction mechanism. Activation energies for the isomerizations of the solvated structures to the inserted ones in the Au − /Au + HR reactions (R = OCH 3 and OH) are predicted to be much higher than those for the Au − /Au + CH 3 SH reactions, supporting the experimental observation. Theoretical calculations provide the evidence that the intriguing [HAuSCH 3 ] − product may be formed by the attachment of the electron onto the neutral HAuSCH 3 species or the isomerization from the anionic [Au· · ·HSCH 3 ]− one. These findings should be helpful for understanding the feature that the thiols are able to form the staple motifs, whereas CH 3 OH and H 2 O are not. © 2013 AIP Publishing LLC. [http://dx

Photoelectron Imaging and Theoretical Study on Nascent Hydrogen Bond Network in Microsolvated Clusters of Au–(CH3OH)n (n = 1–5)

“…The bands in the photoelectron spectrum represent the electron binding energies of photodetachment transitions from the ground state of the anionic cluster to the ground or excited states of corresponding neutral cluster. Two bands (X and A) present in the Au – (CH 3 OH) 1,2 clusters, blue-shifting by about 0.49 and 0.94 eV relative to the Au – . Thus, the X and A bands in each cluster should be due to the ground and excited states of the solvated clusters, respectively.…”

“…In the previous studies of the ion–molecule reactions of Au – with H 2 O, CH 3 OH, and CH 3 SH, the solvated [Au···HR] − and inserted [HAuR] − products have been experimentally observed for R = SCH 3 , whereas only solvated [Au···HR] − products have been found for R = OCH 3 and OH . In this work, we present a joint photoelectron imaging and ab initio calculation study on the solvation growth patterns for the clusters of Au – (CH 3 OH) n ( n = 1–5).…”

“…In the gas-phase experiments, a number of solvated metal ions have been detected through collision-induced dissociation (CID), , guided ion-beam mass spectrometry (GIBMS), ion/neutral chemistry, high-pressure mass spectrometry (HPMS), , electron-capture dissociation (ECD), ,, infrared photodissociation (IRPD) spectroscopy, , photoelectron spectroscopy (PES), − etc. In particular, IRPD and PES have been widely used to characterize the structures of the cluster ions. − Extensive gas-phase spectroscopic and theoretical investigations have been carried out on the solvation of coinage metal ions, especially for gold. ,− One of the key issues focuses on whether the coinage metal ions are surface solvated or interior solvated states. Coordination and solvation structures of metal cations (i.e., Mg + (H 2 O) 1–4 , Mg + (CH 3 OH) 1–4 , Ag + (H 2 O) 1–4 , , Cu + (H 2 O) 1–7 , , and M + (H 2 O) 2–5 (M = Li, Na, K, and Cs) , ) have been probed via infrared spectroscopy.…”

Comparison of Conventional and Nonconventional Hydrogen Bond Donors in Au– Complexes

“… 5 Au – [men] exhibits similar shifts in VDE to Au – [CH 3 SH] (ΔeBE X = 0.42 eV) and Au – [H 2 O] (ΔeBE X = 0.45 eV). 26 , 73 In both spectra, there is a small peak centered at 2.31 eV, which has been attributed to photodetachment of background Au – caused by dissociation of the complexes during acceleration.…”

“…Au – [3-HTHF] and Au – [ala] show larger shifts in VDE compared to other Au – ···HO interacting complexes, such as Au – [H 2 O] and Au – [CH 3 OH] (ΔeBE X = 0.51 eV). 26 , 73 However, the interactions of Au – with nucleobases, studied by Cao et al, produced much greater VDE shifts (ΔeBE X = 0.93–1.13 eV). 32 …”