New hydrazone o-HO-phenylhydrazo-β-diketones (OHADB), R(1)NHN═CR(2)R(3) [R(1) = HO-2-C(6)H(4), R(2) = R(3) = COMe (H(2)L(1), 1), R(2)R(3) = COCH(2)C(Me)(2)CH(2)CO (H(2)L(2), 2), R(2) = COMe, R(3) = COOEt (H(2)L(4), 4); R(1) = HO-2-O(2)N-4-C(6)H(3), R(2)R(3) = COCH(2)C(Me)(2)CH(2)CO (H(2)L(3), 3), R(2) = COMe, R(3) = COOEt (H(2)L(5), 5), R(2)R(3) = COMe (H(2)L(6), 6A)], and their Cu(II) complexes [Cu(2)(CH(3)OH)(2)(μ-L(1))(2)] 7, [Cu(2)(H(2)O)(2)(μ-L(2))(2)] 8, [Cu(H(2)O)(L(3))] 9, [Cu(2)(μ-L(4))(2)](n) 10, [Cu(H(2)O)(L(5))] 11, [Cu(2)(H(2)O)(2)(μ-L(6))(2)] 12A and [Cu(H(2)O)(2)(L(6))] 12B were synthesized and fully characterized, namely, by X-ray analysis (4, 5, 7-12B). Reaction of 6A, Cu(NO(3))(2) and ethylenediamine (en) leads, via Schiff-base condensation, to [Cu{H(2)NCH(2)CH(2)N═C(Me)C(COMe)═NNC(6)H(3)-2-O-4-NO(2)}] (13), and reactions of 12A and 12B with en give the Schiff-base polymer [Cu{H(2)NCH(2)CH(2)N═C(Me)C(COMe)═NNC(6)H(3)-2-O-4-NO(2)}](n) 14. The dependence of the OHADB tautomeric equilibria on temperature, electronic properties of functional groups, and solvent polarity was studied. The OHADB from unsymmetrical β-diketones exist in solution as a mixture of enol-azo and hydrazo tautomeric forms, while in the solid state all the free and coordinated OHADB crystallize in the hydrazo form. The relative stabilities of various tautomers were studied by density functional theory (DFT). 7-14 show catalytic activities for peroxidative oxidation (in MeCN/H(2)O) of cyclohexane to cyclohexanol and cyclohexanone, for selective aerobic oxidation of benzyl alcohols to benzaldehydes in aq. solution, mediated by TEMPO radical, under mild conditions and for the MW-assisted solvent-free synthesis of ketones from secondary alcohols with tert-butylhydroperoxide as oxidant.

Novel copper(II) 2-N-arylpyrrolecarbald-

In situ generated copper(II)-diimine complexes combined with TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl radical) were studied in the oxidation of benzylic alcohols, the focus being on enviromentally benign reaction conditions. In this respect, reactions were studied in aqueous alkaline solutions and dioxygen was used as an end oxidant. This simple catalytic system turned out to be highly efficient and selective in the oxidation of primary and secondary benzylic alcohols to their corresponding carbonyl compounds. Under optimised reaction conditions [5 mol % of TEMPO, 3 mol % of copper (II) diimine, pH 12.6-13.5, 80 8C, 10 bar O 2 ] benzyl alcohol was quantitatively and selectively oxidised to benzaldehyde. According to ESI-MS studies, coordination of TEMPO, as well as deprotonated benzyl alcohol to the parent copper-diimine complex in aqueous solutions is feasible. Supported by these observations a plausible reaction mechanism is proposed for the oxidation reaction.

A new water-soluble β-diketone azo derivative Ϫ 3-(5-chloro-2-hydroxy-3-sulfophenylhydrazo)pentane-2,4-dione (H 3 L, 1) Ϫ was synthesized and found to be stable in DMSO solution and in the solid state in the hydrazo tautomeric form.

The in situ prepared complex based on copper(II) sulfate and 1,10-phenanthroline (phen) and its performance in the catalytic oxidation of veratryl alcohol (3,4-dimethoxybenzyl alcohol) to veratraldehyde with O 2 in alkaline aqueous solutions have been studied. In aqueous solution, the structure of Cu-phen complexes varies with reaction conditions; by changing either the copper-to-ligand molar ratio or the pH, the amount of coordinated 1,10-phenanthroline and hydroxido ligands in the coordination sphere of copper can be altered in a controlled manner. The highest activities are achieved in the pH range 12.6-13.3, which correlates with the presence of the [Cu(phen)(OH) 2 ] species according to