Hexacoppergermsesquioxanes as complexes with N-ligands: Synthesis, structure and catalytic properties

A simple and versatile strategy of synthesis of cage metallagermaniumsesquioxanes is demonstrated for isolation of Cu 6 -based phenylgermsesquioxanes 1–6. Structure of newly synthesized coppergermsesquioxanes was established by single-crystal X-ray diffraction analysis. General principle of these cages’ topology implies the presence of two linear Cu 3 fragments, coordinated by three pairs of ligands. These are: (i) cyclic germsesquioxanes [PhGeO 1,5 ] 5 , products 1–6, (ii) 1,10-phenanthrolines, (1, 3–5) or 2,2’-bipyridines, (2, 6), (or and (iii) OX species (X = H, 1–2, CH 3 , 3, H and C 2 H 5 O, 4, HCO, 5, CH 3 CO, 6). Appearance of non-expected species (formiate for 5, acetate for 6), resulted from corresponding alcohols used as reaction media, points at easyness of oxidation processes in the conditions of such self-assembling reactions. Catalytic tests showed high activity of complexes 1 and 2 as precatalysts in homogeneous oxidations of alkanes (cyclohexane, methylcyclohexane, n-heptane, cis-1,2-dimethylcyclohexane with hydrogen peroxide in acetonitrile solution. Hydroxyl radicals take part in the reaction. The same complexes catalyze oxidation of alcohols (cyclohexanol, 2-heptanol, 1-phenylethanol) to corresponding ketones with tert-butyl hydroperoxide in almost 100% yield. With the addition of various alkyl ammonium salts, complex 2 could also furnish corresponding amides in high yield. © 2019

  • 1 Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova, dom 28, Moscow, 119991, Russian Federation
  • 2 Peoples’ Friendship University of Russia (RUDN University), ul. Miklukho-Maklaya, dom 6, Moscow, 117198, Russian Federation
  • 3 Pirogov Russian National Research Medical University, ul. Ostrovitianova, dom 1, Moscow, 117997, Russian Federation
  • 4 National Research Center “Kurchatov Institute”, pl. Akad. Kurchatova, dom 1, Moscow, 123182, Russian Federation
  • 5 Boreskov Institute of Catalysis SB RAS, prosp. Akad. Lavrentieva, dom 5, Novosibirsk, 630090, Russian Federation
  • 6 Institut des Biomolécules Max Mousseron, UMR 5247, CNRS, Université de Montpellier, ENSCM, Site Triolet, Place Eugène Bataillon, Cedex 5, Montpellier, 34095, France
  • 7 Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina, dom 4, Moscow, 119991, Russian Federation
  • 8 Plekhanov Russian University of Economics, Stremyannyi pereulok, dom 36, Moscow, 117997, Russian Federation
Ключевые слова
Alkanes; Catalysis; Complexes of copper; Functionalization of CH bonds; Hydroxyl radicals; Metallasilsesquioxanes; Oxidation with hydrogen peroxide
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