Synthetic control of excited-state properties. Tris-chelate complexes containing the ligands 2,2'-bipyrazine, 2,2'-bipyrdine, and 2,2'-bipyrimidine

Journal Article · Wed May 02 00:00:00 EDT 1984 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00321a020· OSTI ID:6549526

Allen, G H; White, R P; Rillema, D P; Meyer, T J

The photophysical and photochemical properties of the series of tris-chelate complexes Ru(bpy)/sub n/(bpyz)/sub 3-n//sup 2 +/, Ru(bpy)/sub n/(bpym)/sub 3-n//sup 2 +/, Ru(bpym)/sub n/(bpyz)/sub 3-n//sup 2 +/, and Ru(bpy)(bpym)(bpyz)/sup 2 +/ (n = 0, 1, 2, 3; bpy = 2,2'-bipyridine, bpyz = 2,2'-bipyrazine, bpym = 2,2'-bipyrimidine) are described. From the results of temperature-dependent lifetime (210-345 K) and room-temperature emission quantum yield measurements have been obtained: (1) k/sub r/ and k/sub nr/, the radiative and nonradiative decay rate constants for the emitting MLCT manifold and (2) kinetic parameters which suggest the intervention of additional excited states. The significant points of the study are the following: (1) trends in k/sub nr/ properties are understandable based on the energy gap law, (2) low-lying dd states strongly influence lifetimes and photochemical instabilities for the complexes Ru(bpyz)/sub 3//sup 2 +/, Ru(bpym)/sub 3//sup 2 +/, Ru(bpy)(bpyz)/sub 2//sup 2 +/, Ru(bpy)(bpym)/sub 2//sup 2 +/, Ru(bpym)(bpyz)/sub 2//sup 2 +/, Ru(bpym)/sub 2/(bpyz)/sup 2 +/, and Ru(bpy)(bpym)(bpyz)/sup 2 +/ at room temperature, and (3) for the complexes Ru(bpy)/sub 2/(bpyz)/sup 2 +/ and Ru (bpy)/sub 2/(bpym)/sup 2 +/ there is no evidence for low-lying dd states and these and/or related mixed-ligand complexes may provide a basis for a new series of photochemically stable Ru-polypyridyl chromophores.

• Research Organization: Univ. of North Carolina, Chapel Hill
• OSTI ID: 6549526
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 106:9
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BIPYRIDINES
EXCITED STATES
PHOTOCHEMICAL REACTIONS
RUTHENIUM COMPLEXES
DECAY
EXPERIMENTAL DATA
AZINES
CHEMICAL REACTIONS
COMPLEXES
DATA
ENERGY LEVELS
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
TRANSITION ELEMENT COMPLEXES
400500* - Photochemistry