Multiple emissions from ruthenium diimines

INOR 669

Elena Ferloni, eferloni@gc.cuny.edu1, Jose L. Zambrana, jzambrana@qc.edu2, Julie C. Colis, jcolis@qc.cuny.edu1, and Harry Gafney, hgafney@qc1.qc.edu3. (1) Department of Chemistry, City University of New York, Queens College, 65-30, Kissena Blvd, Flushing, NY 11367, (2) Department of Chemistry and Biochemistry, Queens College -CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, (3) Chemistry Department, The Graduate School and University Center of the City University of New York, Queens College, 65-30, Kissena Blvd, Flushing, NY 11367
Optical excitation of ruthenium diimines in the 400-nm region leads to relatively strong emission in the 600-700-nm range[1]. Characteristic of emitting ruthenium complexes is the assumption that intersystem crossing occurs from the 1MLCT absorption state, to the lowest energy 3MLCT emissive state with unitary efficiency. Studies of the temperature dependence of these molecules have led to a model wherein the 3MLCT equilibrates amongst other states, changing its decay kinetics. Our results on emission quantum yield and lifetime measurements of [(bpy)2Rudpp]2+ and [(bpy)2RudppH]3+ reveal that the latter is a weak emitter of extremely short lifetime (<16ps). In contrast to the currently accepted model, where only a single emissive state is populated and then equilibrates amongst other states based on a particular set of conditions, the excitation-wavelength dependence of the [(bpy)2RudppH]3+ emission suggests an alternative model in which two different relaxation pathways are available to 1MLCT.
 

Coordination Chemistry: Characterization and Applications
7:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006