Sueli M. Drechsel

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Natural and grafted chrysotile were used as matrices for the immobilization of second generation iron porphyrins. The catalysts obtained were evaluated in the oxidation reaction of cyclohexane, using iodosylbenzene as oxidant agent. The catalyst activity for different conditions was compared with results for the same porphyrins immobilized with 3-APTS grafted disordered silica, obtained from acid-leached chrysotile. Preliminary results have shown that high activity can be obtained with short reaction times, and that the reaction is specific for alcohol.

Synthesis, characterization and catalytic behavior of iron porphyrins immobilized in layered double hydroxides

We report the synthesis, characterization and catalytic behavior of iron(III) porphyrins immobilized in layered double hydroxides (LDH). A combination of EPR, UV-visible spectroscopy and powder X-ray diffraction (PXRD) was used to characterize the products. Three different procedures were used to perform the immobilization of iron porphyrin: a) adsorption into the LDH powder, b) co-precipitation and c) rehydration of calcined LDH. Several different porphyrins (Fe(TSPP), Fe(TCPP), Fe(TPP) and Fe(TDFSPP)) were employed in the study. After characterization, the isolated powders were investigated in the oxidation reaction of cyclohexane by iodosylbenzene and hydrogen peroxide in heterogeneous catalysis in comparison to homogeneous media. Some of these immobilized compounds were very good catalysts for this oxidation reaction, stimulating the future investigation of other substrates.

Magneto-structural correlation for binuclear octahedral vanadium(IV)–oxo complexes. Synthesis, structure and magnetic properties of a VIVO2+ complex with a new ligand derived from glycine

The synthesis of a new ligand, H3BBAC (N,N-bis(2-hydroxybenzyl)aminoacetic acid) and its first VIVO2+ complex, [Et3NH]2[OV(BBAC)]2 (1), are presented in order to model the active site of vanadium transferrins. Spectroscopic (EPR, UV-VIS), magnetic properties and crystal data of 1 are discussed and a new magneto-structural correlation turns out to be relevant for binuclear RO-bridging octahedral vanadium(IV)–oxo complexes.

(μ-2,6-Bis{[(2-hydroxy­phenyl)­(2-pyri­dyl­methyl)­amino]­methyl}-4-methyl­phenolato)­bis­[di­aqua­nickel(II)] ace­tate dimethyl­formamide 0.75-hy­drate

The binuclear cation of the title compound, [Ni(2)(C(33)H(29)N(4)O(3))(H(2)O)(4)]C(2)H(3)O(2).C(3)H(7)NO.0. 75H(2)O, was synthesized as a model for the active site of urease. Two tridentate halves of the symmetrical 2, 6-bis[(2-hydroxyphenyl)(2-pyridylmethyl)amino]methyl-4-methylphenol ate (BPPMP(3-)) ligand are arranged in a meridional fashion around the two Ni(II) ions, with the phenoxo O atom bridging the Ni(II) ions. The cation has an approximate twofold rotation axis running through the C-O bond of the bridging phenolate group. Four water molecules complete the octahedral environment of each Ni(II) ion.