Photo- and Vapor-Controlled Luminescence of Rhombic Dicopper(I) Complexes Containing Dimethyl Sulfoxide
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- 作者：Atsushi Kobayashi ; Kahori Komatsu ; Hiroki Ohara ; Waka Kamada ; Yuko Chishina ; Kiyoshi Tsuge ; Ho-Chol Chang ; Masako Kato
- 刊名：Inorganic Chemistry
- 出版年：2013
- 出版时间：November 18, 2013
- 年：2013
- 卷：52
- 期：22
- 页码：13188-13198
- 全文大小：587K
- 年卷期：v.52,no.22(November 18, 2013)
- ISSN：1520-510X
文摘
Halide-bridged rhombic dicopper(I) complexes, [Cu2(渭-X)2(DMSO)2(PPh3)2] (X = I鈥?/sup>, Br鈥?/sup>; DMSO = dimethyl sulfoxide; PPh3 = triphenylphosphine), were synthesized, the iodide complex of which exhibited interesting photochromic luminescence driven by photoirradiation and by exposure to DMSO vapor in the solid state. Single-crystal X-ray diffraction measurements revealed that the iodo and bromo complexes (abbreviated Cu2I2-[O,O] and Cu2Br2-[O,O]) were isomorphous, and that the two DMSO ligands were coordinated to the Cu(I) ion via the O atom in both complexes. Both complexes exhibited bright blue phosphorescence at room temperature (位em = 435 nm, 桅em = 0.19 and 0.14 for Cu2I2-[O,O] and Cu2Br2-[O,O], respectively) with a relatively long emission lifetime (蟿em 200 渭s at 77 K) derived from the mixed halide-to-ligand and metal-to-ligand charge transfer (3XLCT and 3MLCT) excited state. Under UV irradiation, the blue phosphorescence of Cu2Br2-[O,O] disappeared uneventfully and no new emission band appeared, whereas the blue phosphorescence of Cu2I2-[O,O] rapidly disappeared with simultaneous appearance of a new green emission band (位em = 500 nm). On further irradiation, the green emission of the iodide complex gradually changed to bright yellowish-green (位em = 540 nm); however, this change could be completely suppressed by lowering the temperature to 263 K or in the presence of saturated DMSO vapor. The initial blue phosphorescence of Cu2I2-[O,O] was recovered by exposure to DMSO vapor at 90 掳C for a few hours. IR spectroscopy and theoretical calculations suggest that the DMSO ligand underwent linkage isomerization from O-coordination to S-coordination, and both the occurrence of linkage isomerization and the removal of DMSO result in contraction of the rhombic Cu2(渭-I)2 core to make the Cu路路路Cu interaction more effective. In the contracted core, the triplet cluster-centered (3CC) emissive state is easily generated by thermal excitation of the 3XLCT and 3MLCT mixed transition state, resulting in the green to yellowish-green emission. In contrast, the Cu路路路Cu distance in Cu2Br2-[O,O] is considerably longer than that of Cu2I2-[O,O], which destabilizes the 3CC emissive state, resulting in the nonemissive character.