Photo-reversible Valence Tautomerism in a Co Compound |
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| Authors: | Osamu Sato Shinya Hayami Zhong-ze Gu Kazuyuki Takahashi Rie Nakajima Akira Fujishima |
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| Affiliation: | 1. Special Research Laboratory for Optical Science , Kanagawa Academy of Science and Technology , KSP Bldg. East 412, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa , 213-0012 , Japan;2. Department of Chemistry, Faculty of Sciences , Kyushu University , 6-10-1 Hakozaki, Higashi-ku, Fukuoka , 812-8581 , Japan;3. Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo , 113-8656 , Japan |
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| Abstract: | Photo-illumination effects have been measured for the compound [Co III-LS (tmpda)(3,6-DBSQ)(3,6-DBCat)]. When the aforementioned compound was illuminated at 5 K, the magnetization value increased from w eff = 1.87 to 2.03 w B . The absorption spectra after illumination show that the absorption band at around 730 nm, which is characteristic of the [Co II-HS (tmpda)(3,6-DBSQ) 2 ] state, increased in intensity and that the charge transfer band from 3,6-DBCat to 3,6-DBSQ at 2500 nm was reduced in intensity. IR spectra show that the C-O stretching peak at 1279 cm m 1 is decreased in intensity. These results confirm that a photo-induced intra-molecular electron transfer, [Co III-LS (tmpda)(3,6-DBSQ)(3,6-DBCat)] to; [Co II-HS (tmpda)(3,6-DBSQ) 2 ], was induced. The lifetime of the metastable state at 5 K was 15 min. Furthermore, it was found that reverse valence tautomerism can be induced by exciting the Co II-HS to 3,6-DBSQ charge transfer band in metastable [Co II-HS (tmpda)(3,6-DBSQ) 2 ]. |
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| Keywords: | Valence Tautomerism Photo-induced Electron Transfer Long Lifetime |
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