Photophysical behavior and intramolecular energy transfer in Os(II) diimine complexes covalently linked to anthracene.
The photophysical behavior of two Os(II) complexes having a bipyridine ligand with anthracene attached directly to the bipyridine (4-(9-anthryl)-2,2'-bipyridine, bpy-AN) is reported. The two complexes [(bpy)2Os(bpy-AN)]2+ and [(bpy-AN)2Os(CO)Br]+ have (3)MLCT excited states that differ in energy by less than 800 cm(-1). Despite this fact, the observed photophysical behavior of the two complexes is entirely different. The complex with the higher energy 3MCLT state, [(bpy-AN)2Os(CO)Br]+, is nonemissive at room temperature, but has a long lived excited state that is localized on the 3(pi-pi*) state of the anthracene substituent. The other complex, [(bpy)2Os(bpy-AN)]2+, exhibits emission at room temperature and has a transient absorption spectrum that is consistent with a localized 3MLCT state. The excited state decay behavior of the two complexes can be fit well assuming a model in which noninteracting 3MLCT and 3(pi-pi*) states are in equilibrium.
Balazs
G Christian
GC
Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
del Guerzo
André
A
Schmehl
Russell H
RH
D000873:Anthracenes / Q000138:chemical synthesis / Q000737:chemistry*; D004735:Energy Transfer; D007097:Imines / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D009992:Osmium / Q000737:chemistry*; D010777:Photochemistry
D000873:Anthracenes; D007097:Imines; D009942:Organometallic Compounds; D009992:Osmium