Luminescent Osmium Diimine Complexes
Elise G. Megehee, Department of Chemistry, St. John’s College of Liberal Arts and Sciences
Pantea Menhaji, Irma Tertulien, and Joseph Capritto, St. John’s College of Liberal Arts and Sciences Students
Abstract
Osmium metal complexes are of interest as they exhibit visible luminescence upon excitation with visible or ultraviolet light and as such are possible models of photosynthetic reaction centers, possible energy and electron transfer agents, and possible photochemical or electrochemical reaction catalysts. We have undertaken a series of studies to determine the versatility of (2,2-bipyridine)-carbonyl-(triflato)osmium(II) as a precursor to new luminescent osmium complexes. Our syntheses have been divided into four areas:
- Synthesis of alkyl complexes whose syntheses give two structural isomers with very different chemical and physical properties.
- Attachment of various phosphine ligands to determine how different electron donating and electron withdrawing groups attached to the phosphine affect the physical properties of the osmium complex.
- Synthesis of ten different Osmium triflato intermediates made with other dinitrogen ligands to show the versatility of this synthetic method.
- Synthesis of osmium pyridine and osmium-porphyrin dyads of the various osmium triflato precursors to determine the effect of various electron donating and electron withdrawing groups on the dinitrogen ligand.