Polymer anchored Schiff base complexes of transition metal ions and their catalytic activities in oxidation of phenol

Gupta, K. C.; Sutar, Alekha Kumar

doi:10.1016/j.molcata.2007.03.025

Cited by 82 publications

(24 citation statements)

References 36 publications

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“…A variety of applications, including biological [4,5], analytical [6,7] and industrial use as catalysts [8,9], make the Schiff-base ligands and their complexes to be of great importance. It has been shown that the chain length of Schiff bases influences catalytic activity of their complexes [10].…”

Section: Introductionmentioning

confidence: 99%

N,N′-Dipyridoxyl(1,8-diamino-3,6-dioxaoctane) Schiff-base: Synthesis, experimental and theoretical identification

Beyramabadi¹,

Morsali²,

Bozorgmehr³

et al. 2013

Bull. Chem. Soc. Eth.

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ABSTRACT. The N,N′-dipyridoxyl(1,8-diamino-3,6-dioxaoctane) (=H2L) Schiff-base has been synthesized and characterized by IR, 1 H NMR, mass spectrometry and elemental analysis. Its optimized geometry and theoretical vibrational frequencies have been computed using density functional theory (DFT) method via the B3LYP functional. Also, its 1 H and 13 C NMR chemical shifts have been calculated at the same computational level. In optimized geometry of the H2L, the two pyridine rings are perpendicular to each other. The phenolic hydrogens are engaged in intramolecular-hydrogen bonds with the azomethine nitrogens.

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Section: Introductionmentioning

confidence: 99%

N,N′-Dipyridoxyl(1,8-diamino-3,6-dioxaoctane) Schiff-base: Synthesis, experimental and theoretical identification

Beyramabadi¹,

Morsali²,

Bozorgmehr³

et al. 2013

Bull. Chem. Soc. Eth.

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“…The 3-MHBdMBn Schiff base was synthesized modifying the procedure reported in the literature. [21] The reaction mixture containing 2-hydroxy-3 -methylbenzaldehyde (20.00 mmol, 2.72 g) and 4-Methylbenzene-1,2-diamine (10.00 mmol, 1.22 g) in methanol was refluxed at 60 0 C for about 1hr. The reaction mixture on cooling at low temperature produced light orange colored crystals, which were iltered and recrystallized with methanol.…”

Section: Characterization Of 3-mhbdmbn Schiff Base and Itsmentioning

confidence: 99%

“…On doubling the concentration of polymer bound catalyst, the conversion of phenol was doubled, whereas in case of homogeneous conditions, the phenol conversion was increased to 1.7-fold. The activity of metal complexes on polymer supports has normally found to be more in comparison to metal complexes on inorganic supports [20][21][22]. The polymer-supported Schiff base complexes of metal ions also showed variations in the decomposition of hydrogen peroxide with their redox potentials, [20] which provided a useful criterion to explain the activity of metal ions in the oxidation of phenol in the presence of hydrogen peroxide as the oxidant.…”

Section: Introductionmentioning

confidence: 99%

“…The polymer-supported Schiff base complexes of metal ions also showed variations in the decomposition of hydrogen peroxide with their redox potentials, [20] which provided a useful criterion to explain the activity of metal ions in the oxidation of phenol in the presence of hydrogen peroxide as the oxidant. The activity of polymer-supported Schiff base complexes of iron(III), cobalt(II) and nickel(II) ions in the oxidation of phenol [21][22] also showed variation with temperature, time, etc, which might be due to the change in concentration of substrate or catalyst. The oxidation of phenol in the presence of metal complexes of salen and hydrogen peroxide as the oxidant is reported, but catalytic activity of metal complexes of N, N'-bis (2-hydroxy-3 -methylbenzaldehyde) 4-Methylbenzene-1,2-diamine Schiff base (3-MHBdMBn) Schiff base is not reported in the literature; hence, in these investigations an attempt has been made to prepare polymer-supported nickel complex of 3-MHBdMBn Schiff base and to characterize them for their structures and catalytic activity in the oxidation of phenol in the presence of hydrogen peroxide as an oxidant.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Structural Studies of Nickel Complex Supported by-ONNO-Tetra Dentate Schiff-Base Ligand: Efficient Catalysts for Oxidation of Phenol

Sutar¹

2013

IJMSA

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Abstract:The free and polymer anchored complex of nickel [3-MHBdMBn-Ni and P-3-MHBdMBn-Ni], supported by -ONNO-tetradentate Schiff-base ligand are prepared by the reactions of nickel solution with one molar equivalent of unsupported 3-MHBdMBn (N, N'-bis (2-hydroxy-3-methylbenzaldehyde) 4-Methylbenzene-1,2-diamine) or polymer supported (P-3-MHBdMBn) Schiff-base ligands in methanol. The structural study reveal that nickel (II) complex of 3-MHBdMBn Schiff base is square planar in geometry. Complexation of nickel ion increased the thermal stability of 3-MHBdMBn Schiff base. The catalytic activity of nickel complex towards the oxidation of phenol is investigated in the presence of hydrogen peroxide. Experimental results indicate that the reactivity of P-3-MHBdMBn-Ni is dramatically affected by the polymer support over 3-MHBdMBn-Ni and the rate of oxidation (R p ) for unsupported one is 1.28 x 10 -6 mole dm -3 s -1 and for supported analogue is 1.99 x 10 -6 mole dm -3 s -1 .

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“…Literature data show that different metallocomplexes such as metallosalens, metalloporphyrins, metallophthalocyanines and some enzymes are active catalysts in these reactions [4][5][6]. The main limitation in use of macrocyclic complexes is their deactivation as a result of self-oxidation of macrocyclic ligand.…”

Section: Introductionmentioning

confidence: 99%

Selective Oxidation of Phenol in the Presence of Transition-Metal Substituted Polyoxometalates

et al. 2009

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Tetrabutylammonium salts of lacunary Keggin anions with supported Co and Mn cations soluble in organic solvents were prepared and characterized by thermogravimetric analysis, FTIR spectroscopy and X-ray diffraction. These salts were applied as catalysts for phenol oxidation in acetonitrile solution with iodosobenzene diacetate as single oxygen donor. Deposition of cobalt ions in the lacunary Keggin anions strongly increases the catalytic activity. The conversion of phenol is proportional to concentrations of catalyst and single oxygen donor. The dependence of the conversion of phenol on time indicates that the reaction is 1st order with respect to phenol. The catalyst retains its activity after recycling. On the basis of catalytic results reaction mechanism was elucidated.

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Polymer anchored Schiff base complexes of transition metal ions and their catalytic activities in oxidation of phenol

Cited by 82 publications

References 36 publications

N,N′-Dipyridoxyl(1,8-diamino-3,6-dioxaoctane) Schiff-base: Synthesis, experimental and theoretical identification

N,N′-Dipyridoxyl(1,8-diamino-3,6-dioxaoctane) Schiff-base: Synthesis, experimental and theoretical identification

Synthesis and Structural Studies of Nickel Complex Supported by-ONNO-Tetra Dentate Schiff-Base Ligand: Efficient Catalysts for Oxidation of Phenol

Selective Oxidation of Phenol in the Presence of Transition-Metal Substituted Polyoxometalates

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