Formation of Dipyrromethene- and Corrole-Terminated Self-Assembled Monolayers on Gold

The self-assembled monolayer (SAM) approach, credited to Allara and Nuzzo, has opened new possibilities for creating chemically modified surfaces of metals such as: Au, Pt, Ag, Cu, Hg, which could be applied for designing a new class of sensors. In this work, dipyrromethene and corrole derivatives (thiol, sulfide, disulfide and thioacetate) have been applied for gold modification. The characterization of SAMs has been done by: contact angles, cyclic voltammetry and infrared spectroscopy (FTIR). Based on the results obtained, the following conclusions can be made: 1. Thiol derivatives of dipyrromethene form very tightly packed and quite well ordered layers, which show response towards protons. 2. Sulfide derivatives of dipyrromethene layers were very poorly ordered and quite permeable. 3. Thiol- and disulfide-derivatives of corrole form better organized layers on gold than corrole thioacetate. 4. Corrole SAMs show response towards protons. The method of forming better ordered layers of dipyrromethene- and corrole-terminated SAMs and their sensing capabilities will be discussed.