Tyrosine Peptide Template-based Palladium Nanoparticle Catalyst for C-C Coupling Reaction and Dityrosine Crosslinked Perylene Diimide for Photocurrent Generation

Abstract

Proteins and peptides systematically assemble into functional systems by using multiple covalent and non-covalent interactions of 20 amino acids. Among various amino acids, tyrosine has unique properties in helping protein folding and facilitating proton-coupled electron transfer. Recently, many efforts have been conducted to apply the tyrosines properties in fabrication of functional material. In chapter 1, a fabrication method of palladium (Pd) nanostructure using a specifically designed peptide, Tyr-Tyr-Ala-His-Ala-Tyr-Tyr (YYAHAYY), as a template is described. The YYAHAYY peptide induced the formation of flower-like palladium (Pd) nanostructure by controlling its size and shape. The flower-shaped Pd NPs were well-dispersed in water due to the amphiphilic property of YYAHAYY peptide. In addition, the flower-shaped Pd NPs showed excellent catalytic activities in copper-free Sonogashira cross-coupling reaction in water. In chapter 2, a method to self-organize perylene diimides (PDI) into two-dimensional (2D) film at air/water interface through dityrosine crosslinkage is presented. Dityrosine-crosslinking was formed by one-step photo-polymerization of tyrosine-appended PDI without the need of a template. Such assembly is driven by the amphiphilicity of the crosslinked molecules that have the carboxylic group from the tyrosines and the polycyclic aromatic hydrocarbons from the PDIs. Depending on UV irradiation time, the thickness of the film can be controlled. In addition, upon crosslinking, the PDI film is stacked through pi-pi interaction between the PDIs, which induces semi-crystalline property. The resulting dityrosine crosslinked PDI film shows a photo-active property. This simple approach can be expanded into direct fabrication of free-standing and photocurrent generating organic thin films.