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• 作者：Takashi Yoshimura ; Ayumi Matsuda ; Yuki Ito ; Shoji Ishizaka ; Satoshi Shinoda ; Hiroshi Tsukube ; Noboru Kitamura ; Atsushi Shinohara
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：April 5, 2010
• 年：2010
• 卷：49
• 期：7
• 页码：3473-3481
• 全文大小：875K
• 年卷期：v.49,no.7(April 5, 2010)
• ISSN：1520-510X

文摘

Photoluminescent properties of chalcobromide-capped octahedral hexarhenium(III) complexes with terminal bromide ligands [{Re₆Q_8−nBr_n}Br₆]ⁿ⁻⁴ (Q = Se, n = 1 ([1-Se]³⁻), n = 2 ([2a-Se]²⁻ and [2b-Se]²⁻), and n = 3 ([3-Se]⁻); Q = S, n = 1 ([1-S]³⁻), n = 2 ([2a-S]²⁻, [2b-S]²⁻, and [2c-S]²⁻) were studied. The Q₇Br capped complex [{Re₆Q₇Br}Br₆]³⁻ and Q₆Br₂ [{Re₆Q₆Br₂}Br₆]²⁻ (both D_3d and C_2v symmetric geometrical isomers) were successfully separated by column chromatography. All of the chalcobromide-capped complexes studied showed photoluminescence in both crystalline and solution phases. The emission maximum wavelength of the complexes at 296 K spans 853−915 or 868−968 nm in the crystalline phase or in acetonitrile, respectively. The selenobromide-capped complexes showed more intense emission as compared with the thiobromide analogues. The emission quantum yield (Φ_em) and emission lifetime (τ_em) became smaller and shorter, respectively, with an increase in the number of a capping bromide ligand in [{Re₆Q_8−nBr_n}Br₆]ⁿ⁻⁴. In the crystalline phase at 80 K, the emission maximum of the chalcobromide-capped complex shifted to the longer wavelength relative to that at 296 K. The emissive excited-state of the chalcobromide-capped hexarhenium(III) complexes was concluded to originate from the {Re₆Q_8−nBr_n}ⁿ⁺² core with a spin-triplet type. The Φ_em and τ_em values of the {Re₆Q_8−nBr_n}ⁿ⁺² complex were dependent significantly on the symmetry of the hexarhenium core, showing more intense emission for the complex with the higher symmetric core. A linear correlation between natural logarithm of the nonradiative decay rate constant and the emission maximum energy was observed for [{Re₆Q₆Br₂}Br₆]²⁻.