An in situ study of amine and amide molecular interaction on Fe surfaces

Abstract The interfacial bondings formed between N,N′-diethylmethylamine, N-methyldiethanolamine and N,N′-dimethylsuccinamide molecules with iron surfaces have been investigated using Fourier transform infrared spectroscopy (FTIR) and electrochemical spectroscopies. In this case, the interfacial interactions have been evaluated by analyzing ex situ FTIR peaks and probing potential variations upon molecular interactions to Fe surfaces. Moreover, integrated ATR-FTIR and chronovoltammetry analyses in Kretschmann geometry have been employed to probe the interactions between the molecules and Fe surfaces in situ. The results revealed that a charge transfer between molecules and Fe surfaces takes place indicating chemisorption of the molecules on Fe surfaces. In this case, the interaction of N,N′-diethylmethylamine and Fe surface is negligible. However, N-methyldiethanolamine molecules interact with Fe surfaces through the nitrogen atoms. Interaction of N,N′-dimethylsuccinamide molecules and Fe surface is promoted by nitrogen and carbonyl functional groups. Moreover, interactions of N-methyldiethanolamine and N,N′-dimethylsuccinamide molecules to Fe surfaces are encouraged by application of anodic potentials implying that the molecules and Fe surfaces are charged positively and negatively, respectively.