MODELLING OF TRANSITION METAL COMPLEX CATALYSTS IN THE SELECTIVE ALKYLARENS OXIDATIONS WITH DIOXYGEN. THE ROLE OF HYDROGEN-BONDING INTERACTIONS

The different methods of improvement of catalytic activity of transition metal complexes in the oxidation reactions of alkylarens with molecular oxygen are stated briefly. The offered at first by the authors and developed in their works method for control of catalyst activity of transition metal complexes with additives of electron-donor mono- or multidentate exo ligands L-2 in the oxidations of alkylarens (ethylbenzene, cumene) with molecular oxygen into the corresponding hydroperoxides is presented. The modelling of catalytic nickel and iron complexes with the use of ammonium quaternary salts and macro-cycle polyethers as exo ligands-modifiers is described in details. The role of the hydrogen-bonding interactions in the mechanisms of homogeneous catalysis is discussed. The modelling of catalyst activity of complexes Fe(II,III)(acac)(n) with R4NBr (or 18-crown-6) (18C6) in ethylbenzene oxidation in the presence of small amounts of water additives (similar to 10(-3) mol/l) is analysed. The role of microsteps of the chain initiation (O-2 activation), and propagation in the presence of catalyst (Cat + RO2 center dot ->) in the mechanism of nickel- and iron-catalysed oxidation of ethylbenzene is evaluated.