Binding of Bis-(2,2'-Bipyridine)-Carbonyl-Osmium(II) Compounds to Porphyrins Via Imidazole or Pyrimidine
Elise G. Megehee and Alison Hyslop, Department of Chemistry, St. John’s College of Liberal Arts and Sciences
Upon excitation of ultraviolet light into a bipyridine π-π* band, bis-(2,2'-bipyridine)-carbonyl-(5-pyridyl-10,15,20-triphenylporphyrin)-osmium(II) exhibits energy transfer as evidenced by emission from only the porphyrin half of the molecule. When the protons inside the porphyrin are replaced by zinc, the emission is shifted and mainly quenched suggesting that electron transfer may occur. More recently in order to probe this interaction, we have replaced the pyridine with phenylimidazole to increase the bond strength and the distance between the osmium and the porphyrin. We have also changed the orientation of the osmium to porphyrin, by replacing the pyridine with pyrimidine and binding it to the metal inside the porphyrin. We will discuss the synthesis and electronic characterization of these compounds.