Mn-II and Cu-II complexes with arylhydrazones of active methylene compounds as effective heterogeneous catalysts for solvent- and additive-free microwave-assisted peroxidative oxidation of alcohols

Kamran T. Mahmudov, Manas Sutradhar, Luisa M. D. R. S. Martins, M. Fatima C. Guedes da Silva, Alice Ribera, Ana V. M. Nunes, Shahnaz I. Gahramanova, Fabio Marchetti, Armando J. L. Pombeiro

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22 Citations (Scopus)

Abstract

A one-pot template reaction of sodium 2-(2-(dicyanomethylene) hydrazinyl) benzenesulfonate (NaHL1) with water and manganese(II) acetate tetrahydrate led to the mononuclear complex [Mn(H2O)(6)](HL1a)(2)center dot 4H(2)O (1), where (HL1a) -= 2-(SO3-)C6H4(NH)=N=C(C N) (CONH2) is the carboxamide species derived from nucleophilic attack of water on a cyano group of (HL1) . The copper tetramer [Cu-4(H2O)(10)(-) (1 kappa N: kappa O-2: kappa O, 2 kappa N: k(O)-L-2)(2)]center dot 2H(2)O (2) was obtained from reaction of Cu(NO3)(2)center dot 2.5H(2)O with sodium 5-(2( 4,4-dimethyl-2,6-dioxocyclohexylidene) hydrazinyl)-4-hydroxybenzene-1,3-disulfonate (Na2H2L2). Both complexes were characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction. They exhibit a high catalytic activity for the solvent-and additive-free microwave (MW) assisted oxidation of primary and secondary alcohols with tert-butylhydroperoxide, leading to yields of the oxidized products up to 85.5% and TOFs up to 1.90 x 103 h(-1) after 1 h under low power (5-10 W) MW irradiation. Moreover, the heterogeneous catalysts are easily recovered and reused, at least for three consecutive cycles, maintaining 89% of the initial activity and a high selectivity.

Original languageEnglish
Pages (from-to)25979-25987
Number of pages9
JournalRCS Advances
Volume5
Issue number33
DOIs
Publication statusPublished - 2015

Keywords

  • AEROBIC OXIDATION
  • COPPER(II) COMPLEXES
  • BENZYLIC ALCOHOLS
  • NITROXYL RADICALS
  • MILD CONDITIONS
  • IRON COMPLEXES
  • BETA-DIKETONES
  • LIGANDS
  • ALDEHYDES
  • TEMPO

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