Elise G. Megehee

Synthesis and Characterization of Osmium and Ruthenium Imidazole Complexes

Elise G. Megehee, St. John’s College of Liberal Arts and Sciences, Department of Chemistry

Abstract

Osmium(II) and ruthenium(II) bipyridine compounds are if interest because they have long excited state lifetimes and intense absorptions in the visible region of the electromagnetic spectrum.  As such they are of potential use as light harvesting complexes, DNA probes and excited state electron transfer agents.  We have investigated both ruthenium and osmium imidazole containing complexes.  One advantage of the imidazole ligand is that it has two binding sites, the unsubstituted nitrogen or the carbon atom between the two nitrogens if both nitrogens have alkyl groups.  We have prepared a variety of complexes where we vary, the metal, the imidazole and the mode of binding to explore the effect of each of these on the electronic properties of the complexes.  We will discuss the synthesis and electronic characterization of these compounds.

Synthesis and Characterization of Osmium and Ruthenium Pyridine and Alkyl Complexes

Elise G. Megehee, St. John’s College of Liberal Arts and Sciences, Department of Chemistry

Abstract

We have investigated both ruthenium(II) and osmium(II) bipyridine carbonyl alkyl and pyridine containing complexes.  By one synthetic pathway for making the alkyl group complexes, two isomers form in one synthesis, the ratio of which appears to be temperature dependent.  These isomers are very different in color and other physical properties.  We have recently attempted a second method that gives only the minor isomer.  We have also made a series of pyridine complexes that have the potential to bridge two metal centers or to bind to an osmium and a metal inside a porphyrin ring.  We will discuss the synthesis and electronic characterization of these compounds.