Circularly Polarized Luminescence of Chiral Pt(pppb)Cl (pppbH=1‐pyridyl‐3‐(4,5‐pinenopyridyl)benzene) Aggregate in the Excited State |
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| Authors: | Saori Tanaka Dr. Kyohei Sato Kyoko Ichida Dr. Taichi Abe Prof. Taro Tsubomura Prof. Takayoshi Suzuki Prof. Kazuteru Shinozaki |
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| Affiliation: | 1. Department of Materials System Science, Graduate School of Nanobiosystem Sciences, Yokohama City University, Yokohama, Japan;2. Sumitomo Chemical Co. Ltd., Tsukuba, Ibaraki, Japan;3. Department of Materials and Life Science, Seikei University, Tokyo, Japan;4. Department of Chemistry, Faculty of Science, Okayama University, Okayama, Japan;5. (+81)?45‐787‐2413 |
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| Abstract: | We prepared enantiomers of chiral PtII complexes, Pt(pppb)Cl and Pt(pppb)CN (pppbH=1‐pyridyl‐3‐(4,5‐pinenopyridyl)benzene), and measured their CPL (circularly polarized luminescence) spectra for excimer and trimer emission. The contribution of the pinene moiety to CPL was considerably low for the π–π* emission of the monomer but large for MMLCT (metal‐metal‐to‐ligand charge‐transfer) of the excimer and trimer which had a helical structure induced in a face‐to‐face stacking fashion. The trimer CPL for (+)‐Pt(pppb)Cl was larger in intensity than that of excimer CPL; on the other hand, that for (+)‐Pt(pppb)CN was opposite in sign compared with that of excimer CPL. We conclude that differences in the excited‐state structure of the aggregate between Pt(pppb)Cl and Pt(pppb)CN account for the variation in the CPL spectra. By the aid of TD‐DFT calculations it was predicted that the dihedral angle θ(Cl‐Pt‐Pt‐Cl) was 50–60° or 110–140° for Pt(pppb)Cl aggregates and 160° for Pt(pppb)CN aggregates. |
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| Keywords: | circularly polarized luminescence excimer excited-state structure metal-metal interaction platinum complex |
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