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Understanding Bonding Nature of α-Keggin Polyoxometalates [XW12O40]n- (X = Al, Si, P, S): A Generalized Superatomic Perspective

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 176-183页

作者： Li, Rui Shi, Yulei Yu, Famin Wang, Rui Yan, Haitao Teo, Boon K. Wang, Zhigang Capital Normal Univ Dept Phys Beijing 100048 Peoples R China Jilin Univ Coll Phys Key Lab Mat Simulat Methods & Software Minist Educ Changchun 130012 Peoples R China Jilin Univ Inst Atom & Mol Phys Changchun 130012 Peoples R China Jilin Univ Inst Theoret Chem Coll Chem Changchun 130012 Peoples R China Xiamen Univ Coll Chem & Chem Engn State Key Lab Phys Chem Solid Surfaces Xiamen 361005 Peoples R China

alpha-Keggin polyoxometalates (POMs) [XW12O40](n-) (X = Al, Si, P, S) are widely used in batteries owing to their remarkable redox activity. However, the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature. Here, first-principles calculations show that XW12 are core-shell structures composed of a shell and an XO4n- core, both are stabilized by covalent interactions. Interestingly, owing to the presence of a substantial number of electrons in W12O36 shell, the frontier molecular orbitals of XW12 are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model. Detailed analysis indicates that energetically high lying filled molecular orbitals (MOs) have reached unusually high-angular momentum characterized by quantum number K or higher, allowing for the accommodation of numerous electrons. This attribute confers strong electron acceptor ability and redox activity to XW12. Moreover, electrons added to XW12 still occupy the K orbitals and will not cause rearrangement of the MOs, thereby maintaining the stability of these structures. Our findings highlight the structure-activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.

关键词： first principles molecular orbital polyoxometalate redox activity superatom ELECTRONIC SHELL STRUCTURE CORRELATION-ENERGY BASIS-SET DENSITY STABILITY CHEMISTRY heteropolyanions ORBITALS MODEL DFT

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Effects of vanadium(V)-substitution on the oxidative properties of α-Keggin-type heteropolyanion clusters——progress in DFT theoretical studies

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Science China Chemistry 2009年第12期52卷 2096-2105页

作者： WANG JinYue FU XiaoHong WANG Jian HU ChangWei Institute of Applied Chemistry Department of Chemistry and Chemical EngineeringKey Laboratory of Computational Physics in Universities of SichuanYibin UniversityYibin 644007China Key Laboratory of Green Chemistry and Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu 610064China

The redox properties of α-Keggin-type heteropolyanion clusters [XM12O40]n-(X = Si,P; M = Mo,W) mainly depend on their constituent outer metal-oxygen cages {M12O36}. They act as "reservoirs",through which the transfer and transition of electrons and protons may occur. At the atomic and molecular level,the redox properties of these clusters can be controlled and also tuned by modifying the metal M in the cages and the central heteroatom X of the clusters. Combined with relevant experimental results,this review summarizes our recent theoretical investigations of the effect of vanadium substitution on the redox properties of Keggin anion clusters. Theoretical modeling and calculation results showed that the oxidative ability of the modified species was increased by partial substitution of the cage M atoms of the Keggin clusters by vanadium atoms which have lower electronegativity. A linear correlation between the catalytic efficiency per vanadium atom and the microstructures of the vanadium(V)-substituted heteropolyanions [PVnMo12-nO40](3+n)-(n = 1-3) was established for the first time. This relationship may be suitable to interpret the catalytic behavior of the title compounds in the hydroxylation of benzene to phenol,and may also be used in understanding other reactions such as the oxidative dehydrogenation of isobutyric acid and the nitration of adamantine. The establishment of this nearly linear structure-property relationship may lay the foundations of understanding the behavior of the title compounds in homogeneous catalytic oxidation reactions,and may direct the design of future catalysts and the choice of other catalytic reactions.

关键词： polyoxometalates α-Keggin-type heteropolyanions vanadium substitution oxidative property density functional theory (DFT)

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Studies on Redox Properties of Heteropoly Compounds Containing Rare Earth Elements

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Chemical Research in Chinese Universities 1989年第3期5卷 199-205页

作者： Wang Enbo, Lu Xinghong, Zhao Shiliang, Liu Jingfu and Zhang Baojian (Defartment of Chemistry, Northeast Normal University, Changchun)

The redox properties of four series of more than one handred acids and salts of rare earth heteropoly compounds, such as LnHSiMoi2O40, In (PMo11 O39)211-, Ln (PW11 O39)211-, Ln (AsW11 O39)211-, Ln(GeW11O39)213-, Ln(BW11O39)215-, Ln(GaW11O39)216-, Ln(P2Mo17O61)217-, Ln (As2W17O61)217-, Ln2P2Mo18O62and Ln2HP2Mo17VO62(Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, etc. ) which have Keggin, Daw-son and their derivative structures, were studied by means of potentiometric titration, polarography and cy-clovoltammetry. The mechanisms of the redox reactions were supposed-and the orders of redox ability of the heteropoly compounds were concluded. The periodic changes in reduction potentials of Ln(PMo11O39)211-and Ln(P2Mo17O61)2217- with Ln atomic numbers, and the correlation between E1/2 of Ln(XMo11O39)2(?)-(X =P, Ge, Si) and nq2(n is the main quantum number of the central atoms and q is their charges) were found.

关键词： Redox Rare earth heteropolyanions

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Preparation and Characterization of Heteropoly-complex K11[La（GaW11O39H2）2]· xH2O

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Chemical Research in Chinese Universities 1988年第3期 1-8页

作者： Zhu Zhiping, Liu Jingfu, Zhao Benliang Sun Yuhao (Department of Chemistry, Northeast Normal University)

Heteropoly complexes K11[Ln(CaW 11O39H2)21 · x H2O(Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy ) have been prepared and analysed. Some properties such as thermal behavior, IK and UV spectra, X-ray powder diffraction, magne... 详细信息

关键词： Heteropoly complexes Heteropolyacids heteropolyanions

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