Polynucleating Schiff base ligands, poly(2,5- dihydroxyterephthalaldehyde ethylenediamine diprotonated) (PdhterenH2) and poly(2,5-dihydroxyterephthalaldehyde propyldiamine diprotonated) (PdhterpnH2) were synthesized by condensation reactions of 2,5- dihydroxyterephthalaldehyde (dhterH2) with ethylenediamine and propylenediamine, respectively. Insoluble polynuclear manganese(III)-Schiff base complexes, [Mn(n)(Pdhteren)(OAc)(n)] 1 and [Mn(n)(Pdhterpn)(OAc)(n)] 2 were prepared by refluxing manganese(III)-acetate and the respective polymeric Schiff bases in ethanol. The catalase activity of these complexes were studied in aqueous, dimethylformamide and methanol medium. These complexes catalyze the epoxidation of cyclohexene with H2O2 in the presence of imidazole.

S. Vancheesan

1,2 DIAMINOPROPANE

2,5 DIHYDROXYTEREPHTHALALDEHYDE

alcohol

aldehyde derivative

catalase

cyclohexene derivative

Diamine

ethylenediamine

Hydrogen peroxide

ligand

manganese derivative

Methanol

n,n dimethylformamide

POLY(2,5 DIHYDROXYTEREPHTHALALDEHYDE ETHYLENEDIAMINE DIPROTONATED)

POLY(2,5 DIHYDROXYTEREPHTHALALDEHYDE PROPYLDIAMINE DIPROTONATED)

Schiff base

unclassified drug

aqueous solution

article

catalysis

chemical reaction

complex formation

Epoxidation

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

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IIT Madras

Catalase and epoxidation activity of polynuclear manganese(III)–Schiff base complexes

Journal of Molecular Catalysis A: Chemical

Catalytic epoxidation of olefins with molecular oxygen was studied in the presence of a sacrificial aldehyde using polynuclear manganese complexes of ligands, 2,5-dihydroxyterephthalaldehyde ([MnII(dhter)]n) and its Schiff bases ([MnnII(Pdhteren)], [MnnIII(Pdhteren)(OAc)n] and [MnnIII(Pdhterpn)(OAc)n]) under different reaction conditions. Cyclohexene, cyclooctene, styrene, 1-hexene and 1-pentene were used as substrates for epoxidation. The influence of reaction medium, structure of aldehyde and nature of the ligand environment around catalytic metal center on epoxidation reaction was studied. The manganese(II)-Schiff base complex with nitrogen coordinating environment is more stable and effective epoxidation catalyst than the oxygen bound complex, [MnII(dhter)]n. The catalytic system was used under heterogenized homogeneous condition using environmental friendly molecular oxygen as an oxidant. © 2002 Elsevier Science B.V. All rights reserved.

Polynuclear manganese complexes catalyzed epoxidation of olefins with molecular oxygen

Polynuclear manganese complexes of 2,5-dihydroxyterephthalaldehyde (dhterH2) and its Schiff base polymer ligand (PdhterenH2) [Mn(II)(dhter)](n), [Mn(n)(II)(Pdhteren)] and [Mn(n)(III)(Pdhteren)(OAc)(n)] were synthesized. The manganese complexes were characterized by elemental analysis, thermal analysis, IR and EPR spectroscopic techniques. Catalytic epoxidation of olefins with hydrogen peroxide was studied using the above manganese complexes under heterogenized homogeneous reaction conditions in the presence of a base. The effect of imidazole and olefin concentrations on effective oxygen transfer were studied. [Mn(n)(II)(Pdhteren)] and [Mn(n)(III)(Pdhteren)(OAc)(n)] are more efficient than the oxygen-bonded manganese complex [Mn(II)(dhter)](n) for the activation of hydrogen peroxide. (C) 2000 Elsevier Science B.V.

Synthesis, characterization and catalytic activity of polynuclear manganese complexes of 2,5-dihydroxyterephthalaldehyde for epoxidation of olefins with H2O2

Physical Chemistry Chemical Physics

Inside back cover

ChemInform

ChemInform Abstract: Aliphatic Hydroxylation Catalyzed by Iron(III) Porphyrins.

Journal of the Chemical Society, Chemical Communications

Effect of the ligating anion on the catalase activity of dinuclear manganese(II) complexes of Schiff-base macrocycles

Cell Biochemistry and Function

Manganese redox enzymes. V. L. Pecoraro (Ed.). VCH Publishers: Weinheim, New York and Cambridge. x + 290 pages, 186 DM (£70) (1992)

J. Chem. Soc., Dalton Trans.

Geometrical significance of a µ-phenoxo-bis(µ-carboxylato)dimanganese core as an active-site model of manganese catalase

Catalase and epoxidation activity of polynuclear manganese(III)-Schiff base complexes

Journal	Journal of Molecular Catalysis A: Chemical
ISSN	13811169
Open Access	No