Polyfunctional activity of metal complexes containing 2,6-Di-tert-butylphenol in catalytic oxidation

The results of the investigations of metal complexes containing 2,6-di-tert-butilphenol in the ligand environment in catalytic homogeneous oxidation of organic compounds are reviewed. The liquid-phase oxidation of hydrocarbons, olefins, aminophenol and unsaturated fatty acids by molecular oxygen in the presence of phthalocyanines, porphyrins, σ-aryl and π-allyl transition metal complexes is described. The change of the reactivity of organometallic and coordination compounds by oxidation of the redox active phenolic group opens up the possibility to use them as polyfunctional catalytic systems showing positive and/or negative catalytic effects.     

Heteropoly acid as a novel efficient catalyst for Fries rearrangement

Heteropoly acid H3PW12O40 is a very efficient and environmentally benign catalyst for the Fries rearrangement of phenyl acetate in homogeneous or heterogeneous liquid-phase systems at 100-150 degrees C.     

Electronic structure of uracil-like nucleobases adsorbed on Si(001): uracil,thymine and 5-fluorouracil

We study the electronic properties of the Si(001):Uracil, Si(001):Thymine, andSi(001):5-Fluorouracil systems, focusing on the Si dimer-bridging configuration withadsorption governed by carbonyl groups. While the overall structural and electronicproperties are similar, with small differences due to chemical substitutions, much largereffects on the surface band dispersion and bandgap show up as a function of the molecularorientation with respect to the surface. An off-normal orientation of the molecular planesis favored, showing larger bandgap and lower total energy than the upright position. Wealso analyze the localization of gap-edge occupied and unoccupied surface states.     

(4+2) Dimerization of imides of arylmaleic acids in the presence of the 3,5-dimethyl-1H-pyrazole and 2,6-lutidine

Imides of arylmaleic acids in the presence of 3,5-dimethyl-1H-pyrazole underwent (4+2) dimerization under heating in chlorobenzene within 24 h to afford 1,2,3,3a,3b,4,5,6,6a,10b-decahydrobenzo[e]pyrrolo[3,4-g]isoindole-1,3,4,6-tetraones in good yields. It was established that during the heating of imides of arylmaleic acid in 2,6-lutidine at 100 °C the (4+2) dimerization products containing a lutidine fragment are obtained.     

EPR Study of Ligand Effects in Spin Triads of Bis(o-Semiquinonato)Copper(II) Complexes

We report the X-band (9 GHz) electron paramagnetic resonance (EPR) study of series of bis(o-semiquinonato)copper(II) complexes with different ligands. It was found previously, that exchange interactions in spin triads of these compounds are very sensitive to the structure of the ligand coordinated to the central copper(II) ion. Ligand moderates the copper–radical and radical–radical exchange interactions and strongly changes the magnetic properties of the compound. Depending on a ligand, ferromagnetic or antiferromagnetic character of exchange dominates in the system. The EPR study of these complexes allowed us to obtain information on zero-field splitting parameters and their distributions in the studied compounds. The EPR results compliment previously obtained spectroscopic data on these compounds and suggest the pronounced plasticity of the clusters manifested in the broad distributions of their rhombicity parameters.