Formation, Characterization and Stability of Methyl Selenolate Monolayers on Au(111): An Electrochemical, High Resolution Photoemission Spectroscopy and DFT Study

FERNANDO P. COMETTO; CECILIA A. CALDERÓN; MAURICIO MORÁN; GUSTAVO RUANO; HUGO ASCOLANI; GUILLERMO ZAMPIERI; PATRICIA PAREDES OLIVERA; EDUARDO M. PATRITO

AMER CHEMICAL SOC

Lugar: Washington; Año: 2014 vol. 30 p. 3754 - 3754

e investigated the mechanism of formation and stability of self-assembled monolayers (SAMs) of methylselenolate on Au(111) prepared by the immersion method in ethanolic solutions of dimethyl diselenide (DMDSe). The adsorbed species were characterized by electrochemical measurements and high-resolution photoelectron spectroscopy (HR-XPS). The importance of the head-group on formation mechanism and the stability of the SAMs was addressed by comparatively studying methylselenolate (MSe) and methylthiolate (MT) monolayers. Density Functional Theory (DFT) calculations were performed to identify the elementary reaction steps in the mechanisms of formation and decomposition of the monolayers. Reductive desorption and HR-XPS measurements indicated that a MSe monolayer is formed at short immersion times by the cleavage of the Se−Se bond of DMDSe. However, the monolayer decomposes at long immersion times at room temperature, as evidenced by the appearance of atomic Se on the surface. Th