Structural and EPR/ENDOR/ESEEM spectroscopic investigations of a vanadomolybdate Keggin-type polyoxometalate in organic solvent

Alexander M. Khenkin, Patrick Carl, Debbie Baute, Arnold M. Raitsimring, Andrei V. Astashkin, Linda J.W. Shimon, Daniella Goldfarb, Ronny Neumann

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An EPR spectrum of as synthesized [G.A. Tsigdinos, C.J. Hallada, Inorg. Chem. 7 (1968) 437-441], orange colored, H5PV2Mo10O40 polyoxometalate showed the presence of a reduced vanadium(IV) addenda atom. Surprisingly, further 31P ENDOR (electron-nuclear double resonance) measurements indicated the absence of a phosphorous heteroatom leading to the suggestion that H5VVVIVMo11O40 exists as a previously unrecognized impurity in the typically synthesized H5PV2Mo10O40 compound. H5/4PVVO4VIV/VMo11O36 was then synthesized in low yield (0.8 mol%) by omitting the addition of phosphate in a typical H5PV2Mo10O40 preparation. The molecular formulation and structure was supported by X-ray crystallography, infrared and mass spectrometry. Further use of EPR/ENDOR/ESEEM (electron-spin echo envelope modulation) allowed the formulation of [VVVIVMo11O40]5- as [VVO4VIVMo11O36]5-. Accordingly, the polyoxometalate has a multiscripts(VO, 4, mml:none(), mml:none(), 3 -) heteroatom core with 11 molybdenum addenda and one VO2+ moiety at the polyoxometalate surface. The redox potential and the catalytic activity of the new vanadomolybdate polyoxometalate compound were essentially identical to the often-studied H5PV2Mo10O40 polyoxometalate isomeric mixture.

Original languageEnglish
Pages (from-to)3072-3078
Number of pages7
JournalInorganica Chimica Acta
Issue number9
Publication statusPublished - Jun 1 2006



  • EPR
  • Keggin
  • Polyoxometalate
  • Vanadomolybdate

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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