Photolysis kinetics of 4-(2-(4'-pyridinyl)ethynyl)benzenic diazonium salt and characterization of its self-assembled monolayer film

In this paper, the photolysis kinetics of conjugate 4-(2-(4'-pyridinyl)ethynyl)benzene diazonium salt in acetonitrile and in solid-phase films was investigated by UV-Vis absorption spectroscopy after exposure to ultra-violet light (250 W, 245 nm). Results show that the photolysis kinetics follows first order reaction kinetics and the polar acetonitrile solvent causes the diazonium group to photodecompose more easily. In addition, X-ray photoelectron spectroscopy (XPS) and electrochemical analysis were used to confirm the formation of 4-(2-(4'-pyridinyl)ethynyl) benzene monolayer films which were anchored onto the surface of quartz and indium-tin-oxide (ITO) glass slides by covalent bonds. This method sets the stage for the successful design of organic-metal containing ultrathin films based on a layer-by-layer self-assembly technique.