Electron Localization of Polyoxomolybdates with 蔚-Keggin Structure Studied by Solid-State 95Mo NMR and DFT Calculation

详细信息    查看全文

• 作者：Takahiro Iijima ; Toshihiro Yamase ; Masataka Tansho ; Tadashi Shimizu ; Katsuyuki Nishimura
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：April 3, 2014
• 年：2014
• 卷：118
• 期：13
• 页码：2431-2441
• 全文大小：480K
• 年卷期：v.118,no.13(April 3, 2014)
• ISSN：1520-5215

文摘

We report electron localization of polyoxomolybdates with 蔚-Keggin structure investigated by solid-state ⁹⁵Mo NMR and DFT calculation. The polyoxomolybdates studied are the basic 蔚-Keggin crystals of [Me₃NH]₆[H₂Mo₁₂O₂₈(OH)₁₂{MoO₃}₄]路2H₂O (1), the crystals suggested to have a disordered {蔚-Mo₁₂} core of [PMo₁₂O₃₆(OH)₄{La(H₂O)_2.75Cl_1.25}₄]路27H₂O (2), and the paramagnetic Keggin crystals of [H₂Mo₁₂O₃₀(OH)₁₀{Ni(H₂O)₃}₄]路14H₂O (3). The spectra of ⁹⁵Mo static NMR of these samples were measured under moderate (9.4 and 11.7 T) and ultrahigh magnetic fields (21.8 T). From spectral simulation and quantum chemical calculation, the NMR parameters of the chemical shift and quadrupole interactions for ⁹⁵Mo were estimated. By the analysis based on the result for 1, it was found for 2 that although the {蔚-Mo₁₂} core is disordered, the eight d¹ electrons in it are not completely localized on four Mo鈥揗o bonds. Furthermore, it was shown for 3 that the d¹ electrons are localized to make the Mo鈥揗o bonds, while the unpaired electrons are also almost localized on the paramagnetic Ni^II ions.