The chemistry of the metal ion contained in porphyrin complexes is of very wide and general interest. Because these complexes play a key role in biology, in catalysis, in sensing, and in organic electronics, their chemical and physical processes have been widely studied in the solid state and in solution. It has only been in very recent times, however, that their single molecule chemistry has been probed at the solution-solid interface. Scanning tunneling microscopy (STM) has allowed us to monitor, at the single molecule level, reactions between surface supported metal porphyrins and molecular species like oxygen, imidazole, and other reactive species that can bind as ligands to the metal. These STM studies have clearly demonstrated that the chemistry of the supported metal porphyrin can be very different than in solution. The application of DFT methods has further allowed us to probe the nature of the substrate-porphyrin-ligand interaction relative to the case where no substrate is present. Whenever the porphyrin is supported on a conducting substrate there is a complex charge exchange process that helps stabilize the molecular binding. In some cases, the interaction is such that even the spin state of the metal ion differs on the surface relative to the same complex in solution or gas phase. We will present some particular examples of STM and DFT studies of this new chemistry.

Axial binding to supported metal porphyrins at the solution-solid interface

253rd National Meeting (2017)

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