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The “Peroxo Perrhenic Acid” H 4 Re 2 O 13 : An Oxygen‐Rich Metal Peroxide and Oxidation Catalyst
Author(s) -
Herrmann Wolfgang A.,
Correia João D. G.,
Kühn Fritz E.,
Artus Georg R. J.,
Romã Carlos C.
Publication year - 1996
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.19960020208
Subject(s) - rhenium , chemistry , adduct , catalysis , molybdate , hydrogen peroxide , peroxide , medicinal chemistry , molybdenum , metal , oxygen , diglyme , transition metal , inorganic chemistry , polymer chemistry , organic chemistry , solvent
The rhenium oxides Re 2 O 7 and ReO 3 react with hydrogen peroxide solutions yielding peroxo complexes that efficiently catalyze the oxidation of olefins, aromatics, and certain organometallic compounds. In contrast, related oxides of molybdenum (MoO 3 ) and vanadium (V 2 O 5 ) do not activate H 2 O 2 under comparable conditions. The active rhenium peroxo complex was isolated from the system Re 2 O 7 /H 2 O 2 : the crystalline red‐orange, explosive compound of formula H 4 Re 2 O 13 is the most oxygen rich rhenium compound isolated to date. Its structure resembles a “peroxo perrhenic acid”. The binuclear compound could be isolated in the form of a diglyme adduct, structurally defined as two corner‐sharing pentagonal bipyramids with apical oxo and aquo ligands; the equatorial positions are occupied by the bridging oxygen and by n 2 ‐peroxo groups (two [O 2 ] 2− ligands per rhenium). In contrast to the known complex [CH 3 ReO(O 2 ) 2 ].H 2 O, the new peroxo species [O{ReO(O 2 ) 2 .H 2 O} 2 ] decomposes hydrolytically during the catalytic cycle and can thus not compete in terms of catalytic activity in oxidation reactions involving H 2 O 2 . Hydrolysis yields “perrhenic acid” Re 2 O 7 .2H 2 O, the diglyme adduct of which compound was also characterized by means of an X‐ray diffraction analysis.