Pt2Cl82– Dimer Formation of [Bmim]2PtCl4 Ionic Liquid When Confined in Silica Nanopores

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• 作者：Cheng Li ; Yaxing Wang ; Xiaojing Guo ; Zheng Jiang ; Fangling Jiang ; Wenli Zhang ; Wenfa Zhang ; Haiying Fu ; Hongjie Xu ; Guozhong Wu
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：February 13, 2014
• 年：2014
• 卷：118
• 期：6
• 页码：3140-3144
• 全文大小：284K
• ISSN：1932-7455

文摘

[Bmim]₂PtCl₄ (Bmim: 1-butyl-3-methylimidazolium) ionic liquid was confined in porous SiO₂ nanoparticles ([Bmim]₂PtCl₄@SiO₂) with an average pore size of 7.1 nm. The structure of [Bmim]₂PtCl₄@SiO₂ was investigated through X-ray diffraction and X-ray absorption fine structure (XAFS). The average coordination numbers of Pt species in [Bmim]₂PtCl₄ and [Bmim]₂PtCl₄@SiO₂ were 4.0 and 5.0, respectively. Parts of Pt²⁺ in [Bmim]₂PtCl₄@SiO₂ were oxidized to form high-valence Pt⁴⁺. The possible forms and structures of Pt in the ionic liquid were analyzed according to the coordination number. XAFS analysis and density functional theory calculations imply the favorable formation of dimer (i.e., Pt₂Cl₈^{2鈥?/sup>) in [Bmim]₂PtCl₄@SiO₂, in which two bridge Cl atoms were connected to two Pt atoms. In addition, Pt₂Cl₈2鈥?/sup> contained mixed-valence platinum (Pt2+ and Pt4+). The results of differential scanning calorimetry also showed that the melting point of this nanoconfined ionic liquid increased.}