Influence of local chemical environment and external perturbations of porphyrins on surfaces

Abstract

Porphyrins and tetrapyrroles play crucial roles in biological processes such as photosynthesis and molecular transport. These nature-based molecules have found application in artificial systems, such as sensing, catalysis, and 2D/3D networks. They are ideal building blocks due to their chemical diversity, stability, and ability to self-assemble on surfaces. Derivatization of the peripheral positions allows for the rational design of magnetic, catalytic, and photochemical properties. Due to this, porphyrins have been used in a variety of natural and artificial systems such as photodynamic therapies and dye-sensitized solar cells. Recently, much work and attention have focused on using specific porphyrin and molecular relatives for molecular electronics due to their robust nature, functionality, and synthesis. The focus of this review is to summarize the mechanisms that affect the internal structure and properties of the molecules and how changes in the local chemical environment alter the electronic properties of the porphyrin. We review the current state of the literature concerning the intermolecular and surface-adsorbate interactions that dictate self-assembly. We will assess the effects that molecule-molecule and molecule-substrate interactions play on the molecule’s properties and the effects that external forces have on the molecular properties. The goal of this review is to dissect the mechanisms responsible for the unique properties that arise from porphyrinic systems adsorbed on surfaces.

Synthesis of extended covalently bound porphyrins on the Au(111) surface

“…The role of the underlying substrate, such as Au(111), can have an influence on the self-assembly and electronic properties of the adsorbate. 20,27–33 Observations of the formation of Au–porphyrin intermediates via solution-based deposition methods of a porphyrin self-assembled monolayer on the Au(111) surface reveal similar features upon surface modification, such as electrochemical reactions. Kim et al discovered that the interaction between metalloporphyrins and the underlying Au(111) substrate results in synergistic effects on the catalytic activity of the oxygen evolution reaction.…”