Ruthenium Complexes Bearing Axially Chiral Bipyridyls: The Mismatched Diastereomer Showed Red Circularly Polarized Phosphorescence |
| |
Authors: | Dr Kazuto Takaishi Yusuke Nakatsuka Hitomi Asano Yuya Yamada Prof?Dr Tadashi Ema |
| |
Institution: | Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Tsushima, Okayama, 700-8530 Japan |
| |
Abstract: | RutheniumII complexes bearing three axially chiral bipyridyl ligands were synthesized as a new family of chiral complex dyes, and Δ-(S)- and Λ-(S)-diastereomers were obtained. The X-ray crystal structure analyses, spectroscopy, and DFT calculations suggested that all the bipyridyls maintained chirality in both the ground and excited states, and the Δ-(S)- and Λ-(S)-isomers are the matched (more relaxed) and mismatched (more constrained) pairs, respectively. The mismatched Λ-(S)-isomer exhibited red circularly polarized phosphorescence (CPP) both in solution and in the solid state. The solution state CPP is the most intense of ruthenium complexes, while the solid state CPP is the first example of them. It is supposed that, for the Λ-(S)-isomer, the six cumulative CH/π interactions suppress further distortion in the T1 state. |
| |
Keywords: | axial chirality biaryls circularly polarized luminescence conformation analysis ruthenium |
|
|