title: Low-Energy and Long-Lived Emission from Polypyridyl Ruthenium(II) Complexes Having A Stable-Radical Substituent.
abstract: Novel polypyridyl ruthenium(II) complexes having a 2,2'-bipyridine (bpy) derivative which possesses a 1,5-dimethyl-6-oxoverdazyl radical (OV) group as a stable-radical substituent were designed and synthesized. The radical-ruthenium(II) complexes showed low-energy/intense MLCT absorption and low-energy/long-lived MLCT emission, and these characteristics of the complexes were explained by the electron-withdrawing nature of the OV group. Furthermore, the radical-substituent effects were enhanced by the presence of the electron-donating methyl groups at the 4- and 4'-positions of bpy in the ancillary ligands. The detailed electrochemical, spectroscopic, and photophysical properties of the complexes were discussed in terms of the systematic modification of the second coordination sphere in the main and ancillary ligands.
authors.affiliation: Department of Chemistry/Division of Molecular Materials Science, Graduate School of Science, Osaka City University , 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Akitaka
authors.identifier: http://orcid.org/0000-0002-0893-5535
authors.initials: A
authors.lastname: Ito
authors.affiliation: Department of Chemistry/Division of Molecular Materials Science, Graduate School of Science, Osaka City University , 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Department of Chemistry/Division of Molecular Materials Science, Graduate School of Science, Osaka City University , 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Teki