Terpyridine-Functionalized NanoSiO2 Multi-Dentate Linkers: Preparation, Characterization and Luminescent Properties of Their Metal–Organic Hybrid Materials

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• 作者：Wen-Jie Wu ; Jing Wang ; Meng Chen ; Dong-Jin QianMinghua Liu
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 2, 2017
• 年：2017
• 卷：121
• 期：4
• 页码：2234-2242
• 全文大小：530K
• ISSN：1932-7455

文摘

Terpyridine- (TPy-) functionalized silica nanolinkers (nanoSiO₂–TPy) have been prepared and used as nanoscale multidentate ligands to coordinate with the transition metal ions (Mⁿ⁺ = Zn²⁺, Fe²⁺, Tb³⁺ and Eu³⁺) for producing luminescent metalated organic–inorganic nanoSiO₂–TPyM hybrid materials. Thermogravimetric analysis has revealed that the covalently attached organic species in the nanoSiO₂–TPy linkers were about 10% in weight. After they were functionalized with the layers of TPy or TPyM, the as-prepared nanoSiO₂–TPy linkers and nanoSiO₂–TPyM hybrids formed aggregates more easily due to an increase of internanoparticle interactions. The ζ-potential of the nanoSiO₂–TPy linkers was about 34.6 mV, which increased to 55 to 60 mV for the nanoSiO₂–TPyM hybrids in the poly(ethylene glycol) 200 (PEG 200) solutions. Under UV radiation, the nanoSiO₂–TPy linkers gave off an emission at about 366 nm (monomer of the linkers) in the PEG 200 solutions with the concentrations below 0.5 mg/mL, which shifted to 374 nm after formation of the nanoSiO₂–TPyM hybrids. The excimers of the nanoSiO₂–TPy linkers and nanoSiO₂–TPyM hybrids can be formed in the PEG 200 solutions with concentrations over 1.0 mg/mL and in solid powders. After the excimer was formed, the energy transfer efficiency from the excited states of the nanoSiO₂–TPy linkers to the central lanthanide ions was largely enhanced. This resulted in strong luminescent emissions from the ions between 480 and 650 nm, designated to the electron transitions ⁵D₄ → ⁷F_n (n = 3, 4, 5, 6) and ⁵D₀ → ⁷F_n (n = 0, 1, 2) of the Tb³⁺ and Eu³⁺ ions, respectively.