CHED 1200 |
| The electronic coupling element (HDA) can be determined from the full-width half maximum and molar absorptivity of the intervalence charge transfer band in the near infrared (NIR). To distinguish this band in metalloporphyrin oligomers from other electronic transitions, the electronic transitions of metalloporphyrin monomers were measured experimentally. Ruthenium and osmium porphyrin cofacial dimers were synthesized and characterized by UV/VIS and NMR spectroscopy. The dimers were then oxidized to the mixed-valence species to identify the intervalence charge transfer band and calculate the coupling element. Based on our empirical studies and theoretical work, we determined that the coupling in cofacial dimers depends mostly on the proximity of the porphyrins whereby electron transfer occurs across overlapping orbitals of mainly porphyrin character. No significant changes in coupling were observed by changing the capping ligand. |
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Undergraduate Research Poster Session: Inorganic Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |