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The catalytic peroxidative oxidation (with H 2 O 2 ) of cyclohexane in an ionic liquid (IL) using the tetracopper(II) complex [(CuL) 2 (μ 4 - O,O′,O′′,O′′′ -CDC)] 2 ·2H 2 O [HL = 2-(2-pyridylmethyleneamino)benzenesulfonic acid, CDC = cyclohexane-1,4-dicarboxylate] as a catalyst is reported. Significant improvements on the catalytic performance, in terms of product yield (up to 36%), TON (up to 529), reaction time, selectivity towards cyclohexanone and easy recycling (negligible loss in activity after three consecutive runs), are observed using 1-butyl-3-methylimidazolium hexafluorophosphate as the chosen IL instead of a molecular organic solvent including the commonly used acetonitrile. The catalytic behaviors in the IL and in different molecular solvents are discussed. [ABSTRACT FROM AUTHOR]

Significant differences in the catalytic activity and selectivity towards cyclohexanol and cyclohexanone are achieved by changing the reactional medium. [Display omitted] • Use of Mo complexes in alternative solvents. • Cleaner process for the important industrial oxidation of cyclohexane reaction. • SC-CO 2 and SC-CO 2 /IL media improved selectivity and recycling. • The use of milder conditions with better TONs and TOFs. The cis -dioxidomolybdenum(VI) complexes [MoO 2 (L1)] (1), [MoO 2 (L2)]·MeOH (2) and [MoO 2 (L3)] (3) were prepared by reaction of [MoO 2 (acac) 2 ] with the corresponding aroylhydrazone Schiff base H 2 L1 = 2,3-dihydroxybenzylidene-2-hydroxybenzohydrazide, H 3 L2 = 2,3-dihydroxybenzylidene-benzohydrazide and H 2 L3 = (3,5-di- tert -butyl-2-hydroxybenzylidene)-2-hydroxybenzohydrazide, respectively. The catalytic activities of these complexes towards cyclohexane (CyH) oxidation were examined and compared in CH 3 CN, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF 6 ]), supercritical carbon dioxide (SC-CO 2), and SC-CO 2 /[bmim][PF 6 ] mixed solvent. The yields in the ionic liquid (IL) are always higher than in CH 3 CN. A very high selectivity towards cyclohexanol is obtained in the SC-CO 2 medium with all three complexes. The catalyst can be recycled with full preservation (3 cycles) of its activity in the SC-CO 2 and SC-CO 2 /IL media. [ABSTRACT FROM AUTHOR]

A phenylcarbohydrazone-based Schiff base type ligand (E)-N′-(2-hydroxy-5-methylbenzylidene)benzohydrazide ( HL ) and its monocopper(II) complex [CuL(NO 3 )(H 2 O)]·(H 2 O) ( CuL ) are synthesized and structurally characterized including single-crystal X-ray crystallography. The DNA interacting efficacy of the synthesized CuL with CT (calf thymus) DNA has been investigated using different spectral and viscosity measurements. The DNA binding constant (K b = 2.1 (±1.11) × 10 5 M −1 ) and binding site size (s = 0.31), viscosity data together with circular dichroism studies, revealed that the CuL could interact with DNA via intercalation. The protein binding ability of CuL with BSA (Bovine Serum Albumin) was investigated by absorption, fluorescence and synchronous fluorescence methods and a static quenching mechanism was observed for their interaction with BSA. CuL acts as an efficient catalyst for the aerobic oxidation of catechols (4-methylcatechol, 3,5-ditertiarybutylcatechol, 3-methoxycatechol and 3-nitrocatechol) to the corresponding quinones, in methanol/0.02 M HEPES medium at pH = 8.0 and at 25 °C. The highest activity is observed for the substituted catechol with the electron donor tert -butyl group, resulting in a turnover frequency (TOF) value of 1.45 × 10 4 h −1 . CuL also mimics the action of other copper enzymes, being capable of catalyzing the peroxidative oxidation of cyclohexane, under in mild conditions and in several media. The best results were obtained in an ionic liquid, with a TOF of 1220 h −1 . [ABSTRACT FROM AUTHOR]