Antimony-Supported Cu4I4 Cuboid with Short Cu–Cu Bonds: Structural Premise for Near-Infrared Thermoluminescence

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• 作者：William V. Taylor ; Ulysses H. Soto ; Vincent M. Lynch ; Michael J. Rose
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：April 4, 2016
• 年：2016
• 卷：55
• 期：7
• 页码：3206-3208
• 全文大小：235K
• ISSN：1520-510X

文摘

Herein we report the synthesis, temperature-dependent X-ray structures (100, 150, 200, 250, 273, and 300 K), and solid-state emissive properties of the antimony–copper(I)–iodo cluster [Cu₄(I)₄(SbⁱPr₃)₄] (1), supported by the trialkylantimony donor SbⁱPr₃. Overall, 1 exhibits a distorted cuboidal structure, wherein a twisting of the “cube” generates an interconnected Cu₄ tetrahedron, as well as long Cu–I and Cu–Sb bonds [e.g., 2.707(2) and 2.571(2) Å]; in the 100 K X-ray structure, the Cu–Cu bonds are quite short [2.761(3) Å]. Solid-state emission spectra of 1 were obtained over a range of temperatures (163–298 K), wherein 1 exhibits only a low-energy emission feature centered near 700 nm (λ_Em = 711 nm, fwhm = 150 nm, and λ_Ex = 390 nm). Because 1 contains no aryl units, the emission spectrum (and absorption) can be unambiguously attributed to the Cu₄I₄ core [no L (pnictogen ligand) component]. The luminescence is sharply attenuated upon warming from 150 to 200 K. An overlaid plot of the emissive properties of 1 and its Cu–Cu bond distances [2.761(3)–2.836(4) Å] reveal that ∼2.80 Å represents a critical crossing point for low-energy thermoluminescence in Cu₄-based clusters.