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Current Inorganic Chemistry

Volume 1 Issue 2
ISSN: 1877-9441
eISSN: 1877-945X

 

   All Titles

  Pyridine Carboxylate Complexes of Mo(II) as Active Catalysts in Homogeneous and Heterogeneous Olefin Epoxidation
  pp.146-155 (10) Authors: Maria Vasconcellos-Dias, Sara Raquel M. M. de Aguiar, Carla D. Nunes, Pedro D. Vaz, Teresa G. Nunes, Maria Jose Calhorda
doi: 10.2174/10146
 
 
      Abstract

[MoBr2(CO)3(L)2] complexes were synthesized with L = nicH (pyridine-3-carboxylate), picH (pyridine-2- carboxylate) and pydcH2 (pyridine 2,6 dicarboxylic acid). New lamellar materials intercalated with molybdenum(II) complexes were prepared by first calcinating the starting lamellar material at 823 K for four hours, to eliminate all the carbonate ions; the layered structure was reconstructed after treatment with a basic solution of either nicH, picH, or pydcH2 in a dmf solution of NaOH at 343 K. Impregnation with a solution of the organometallic precursor [MoX2(CO)3(NCCH3)2] (X= Br, X= I) led to substitution of the nitriles by two L ligands. All the Mo(II) complexes were characterized by FTIR, elemental analysis, and 1H and 13C solution NMR, and the materials by powder X-ray diffraction, FTIR and 13C CP MAS-DD solid state NMR. Both the complexes, their iodide analogues, these new materials (3.80 wt% and 1.25 wt% Mo for pic or pydc) and their iodide analogues (4.54 wt% and 6.33 wt% Mo for pic or pydc) catalyze the epoxidation of ciclooctene and styrene and the chiral olefins R(+)- and S(-)-limonene at 328 K. Higher activity is associated with presence of iodide and nicH.

 
  Keywords: Molybdenum, layered materials, epoxidation, heptacoordination, catalysis, hydrotalcite, Clays, NCCH3, Organometallic Fragments, Epoxidation of Olefins
  Affiliation: Departamento de Quimica e Bioquimica, CQB, Faculdade de Ciencias da Universidade de Lisboa, 1749-016 Lisboa, Portugal.
 
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