Abstract
The geometries and electronic structures of the five isomers of [PV 2Mo10O40]5- and its mono- and direduced species were theoretically investigated by means of B3LYP calculations, with an attempt to understand their role as oxidative catalysts in electron-transfer-initiated processes. The calculations reveal the following features: (a) Either in the gas phase or in a solvent, the reduction of the [PV2Mo10O40]5- produces [PV 2Mo10O40]6,7- ions in which the excess electrons are localized on the vanadium atoms in the corresponding δ orbitals. By contrast, the direduced [PV2Mo 10O40]7- isomers where the one electron is localized on molybdenum are high in energy. Consequently, whereas the five isomers of [PV2Mo10O40]5- have roughly a statistical distribution, in the direduced species, the 1,4-[PV 2Mo10O40]7- isomer becomes more stable than others. (b) The gas-phase reduction of the parent [PMo 12O40]3- anion is exceedingly more favorable (by ca. 250 kcal/mol) than the reduction of [PV2Mo10O 40]5-. By contrast, contribution of the solvent exerts a strong leveling effect and makes the reduction potentials of the two species very similar, (c) Since the reduction of [PV2Mo10O 40O40]5- concentrates high negative charge near the O=VO4 moiety, this negative charge accumulation will act as an attractor that binds the organic radical cation (cation), which causes a subsequent proton transfer to an oxo ligand of the vanadium. As such, in terms of an electron-transfer catalytic effect, the presence of vanadium in [PV 2Mo10O40]5- creates function for the catalyst, (d) The computations reveal that [PV2Mo10O 40]7- is a diradicaloid that possesses two virtually degenerate states, with singlet and triplet spins. Thus, we may expect two-state reactivity (TSR) in the catalytic reactions of [PV2Mo 10O40]5-. Some predictions are made based on these features.
| Original language | English |
|---|---|
| Pages (from-to) | 7711-7719 |
| Number of pages | 9 |
| Journal | Journal of Physical Chemistry C |
| Volume | 111 |
| Issue number | 21 |
| DOIs | |
| Publication status | Published - May 31 2007 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Energy(all)
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The electronic structure of reduced phosphovanadomolybdates and the implications on their use in catalytic oxidation initiated by electron transfer. / Hirao, Hajime; Kumar, Devesh; Chen, Hui; Neumann, Ronny; Shaik, Sason.
In: Journal of Physical Chemistry C, Vol. 111, No. 21, 31.05.2007, p. 7711-7719.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The electronic structure of reduced phosphovanadomolybdates and the implications on their use in catalytic oxidation initiated by electron transfer
AU - Hirao, Hajime
AU - Kumar, Devesh
AU - Chen, Hui
AU - Neumann, Ronny
AU - Shaik, Sason
PY - 2007/5/31
Y1 - 2007/5/31
N2 - The geometries and electronic structures of the five isomers of [PV 2Mo10O40]5- and its mono- and direduced species were theoretically investigated by means of B3LYP calculations, with an attempt to understand their role as oxidative catalysts in electron-transfer-initiated processes. The calculations reveal the following features: (a) Either in the gas phase or in a solvent, the reduction of the [PV2Mo10O40]5- produces [PV 2Mo10O40]6,7- ions in which the excess electrons are localized on the vanadium atoms in the corresponding δ orbitals. By contrast, the direduced [PV2Mo 10O40]7- isomers where the one electron is localized on molybdenum are high in energy. Consequently, whereas the five isomers of [PV2Mo10O40]5- have roughly a statistical distribution, in the direduced species, the 1,4-[PV 2Mo10O40]7- isomer becomes more stable than others. (b) The gas-phase reduction of the parent [PMo 12O40]3- anion is exceedingly more favorable (by ca. 250 kcal/mol) than the reduction of [PV2Mo10O 40]5-. By contrast, contribution of the solvent exerts a strong leveling effect and makes the reduction potentials of the two species very similar, (c) Since the reduction of [PV2Mo10O 40O40]5- concentrates high negative charge near the O=VO4 moiety, this negative charge accumulation will act as an attractor that binds the organic radical cation (cation), which causes a subsequent proton transfer to an oxo ligand of the vanadium. As such, in terms of an electron-transfer catalytic effect, the presence of vanadium in [PV 2Mo10O40]5- creates function for the catalyst, (d) The computations reveal that [PV2Mo10O 40]7- is a diradicaloid that possesses two virtually degenerate states, with singlet and triplet spins. Thus, we may expect two-state reactivity (TSR) in the catalytic reactions of [PV2Mo 10O40]5-. Some predictions are made based on these features.
AB - The geometries and electronic structures of the five isomers of [PV 2Mo10O40]5- and its mono- and direduced species were theoretically investigated by means of B3LYP calculations, with an attempt to understand their role as oxidative catalysts in electron-transfer-initiated processes. The calculations reveal the following features: (a) Either in the gas phase or in a solvent, the reduction of the [PV2Mo10O40]5- produces [PV 2Mo10O40]6,7- ions in which the excess electrons are localized on the vanadium atoms in the corresponding δ orbitals. By contrast, the direduced [PV2Mo 10O40]7- isomers where the one electron is localized on molybdenum are high in energy. Consequently, whereas the five isomers of [PV2Mo10O40]5- have roughly a statistical distribution, in the direduced species, the 1,4-[PV 2Mo10O40]7- isomer becomes more stable than others. (b) The gas-phase reduction of the parent [PMo 12O40]3- anion is exceedingly more favorable (by ca. 250 kcal/mol) than the reduction of [PV2Mo10O 40]5-. By contrast, contribution of the solvent exerts a strong leveling effect and makes the reduction potentials of the two species very similar, (c) Since the reduction of [PV2Mo10O 40O40]5- concentrates high negative charge near the O=VO4 moiety, this negative charge accumulation will act as an attractor that binds the organic radical cation (cation), which causes a subsequent proton transfer to an oxo ligand of the vanadium. As such, in terms of an electron-transfer catalytic effect, the presence of vanadium in [PV 2Mo10O40]5- creates function for the catalyst, (d) The computations reveal that [PV2Mo10O 40]7- is a diradicaloid that possesses two virtually degenerate states, with singlet and triplet spins. Thus, we may expect two-state reactivity (TSR) in the catalytic reactions of [PV2Mo 10O40]5-. Some predictions are made based on these features.
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U2 - 10.1021/jp068673c
DO - 10.1021/jp068673c
M3 - Article
VL - 111
SP - 7711
EP - 7719
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 21
ER -