Photochemistry of tetraaza-tetrapyridopentacene related compounds and their role in small molecule activation

ORGN 109

Wen Guo, wen.guo@wmich.edu and Sherine O. Obare, sherine.obare@wmich.edu. Department of Chemistry, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI 49008
The design of molecular entities capable of storing multiple electrons remains a challenge in photochemistry. Multiple electrons permit processes that are thermodynamically favored, and that cannot be achieved by single electron transfer pathways. We have synthesized a series of 9,11,20,22-tetraaza-tetrapyridopentacene (TATPP) and its related compounds, and have studied their photochemistry. The photo-generated species of the compounds were characterized by UV-visible absorbance and nuclear magnetic resonance spectroscopies, and further confirmed spectroelectrochemically and by theoretical calculations. Density functional theory calculations (B3LYP) were performed based on 6-31G(d,p) basis set via Gaussian03 program. Frequency calculations were performed to identify the local minimum energy of the optimized structure. We demonstrate that the family of TATPP ligands store multiple electrons following photolysis, and that these electrons are efficient toward the reduction of various small molecules such as oxygen and water.