Synchrotron far-infrared RAIRS studies of complex molecules on Cu(110)

Surface‐Driven Keto–Enol Tautomerization: Atomistic Insights into Enol Formation and Stabilization Mechanisms

“…Generally,t he ketone form of neutral carbonyl compounds is more stable than the enol form, [5] therefore the formation of enol species usually requires stabilization by for example,h ydrogen bonding.T he most commonly discussed mechanism of the enol stabilization is related to diketones or ketoesters containing two carbonyl groups.I nt hese compounds,achelated ring-like keto-enol tautomer can be formed with one of the carbonyls being transformed to a À C À O À He ntity and the other carbonyl participating in the stabilization of the enol part of the molecule through hydrogen bonding between the ÀC=Oa nd HÀOÀCÀ functional groups.Numerous studies provided solid experimental proof for the mechanism leading to formation of chelated keto-enol tautomers in diketones and ketoesters. [6] While the enol stabilization is well understood for the compounds comprising two carbonyls,s ignificantly less is known about the enol formation and stabilization for monocarbonyls,i nw hich the intramolecular stabilization is not possible.I nar ecent study by Demers-Carpentier et al [7] on monocarbonyls adsorbed on Pt, an interesting observation on formation of different oligomers,c onsisting of two or three acetophenone molecules,w as reported, which were interpreted as structures comprising exclusively the enol species. As thermal activation, up to 300 Kwas needed to obtain these enol-containing oligomers,t he authors put forward ad issociative type of keto-enol tautomerization mechanism, involving dissociation of aC À Hb ond in methyl group followed by aHdiffusion through the Pt surface to the C = Ogroup.…”

Infrared reflection-absorption spectroscopy of Alq3 thin film on silver surface using synchrotron radiation

“…11 Use of highly brilliant infrared synchrotron radiation ͑IRSR͒ sources enables us to obtain IRAS spectra in the low wave number region. 12,13 In this work, we measured the IRAS spectra of Alq 3 thin film deposited on Ag surface as a function of thickness in the spectral region of 300-500 cm −1 using the SR-IRAS system we constructed. 14 Since the Ag surface may affect the structure of Alq 3 over several layers, we measured IRAS spectra from monolayer to multilayer of Alq 3 .…”

IR Spectroscopy and Spectromicroscopy with Synchrotron Radiation

“…Thorough studies have been performed on Cu and Pt surfaces (Hirschmugl et al 1990;Dumas et al 1997;Surman et al 2002;Baily et al 2003). Other studies identified the bonding nature of organic molecules on metallic surface (Humblot et al 2003).…”