Kinetics of the degradative oxidation of sugar-type ligands catalyzed by copper(II) ions

Ródio, Renata Trinquinato; Pereira, Eleonice Maria; Tavares, Marina Franco Maggi; Ferreira, Ana Maria da Costa

doi:10.1016/s0008-6215(99)00026-9

Cited by 11 publications

(1 citation statement)

References 49 publications

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“…The smaller fragments generated from initial carbohydrates are coordinated to the metallic centre and therefore are eliminated at different temperatures. 44 Similar behaviour was observed in all complexes (see ESI, Fig. 1S, 3S, 5S, 7S, 9S, 11S, 13S and 15S †).…”

Section: Thermogravimetric Analysissupporting

confidence: 79%

Structure characterization of the non-crystalline complexes of copper salts with native cyclodextrins

et al. 2016

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The characterization of non-crystalline complexes is particularly difficult when techniques like X-ray diffraction or NMR cannot be used. We propose a simple procedure to characterize the physicochemical properties of amorphous new coordination compounds between cyclodextrins (CD) and Cu(2+) salts, by means of the integration of the information provided by several techniques including elemental analysis, flame atomic absorption, TGA, UV-Vis diffuse reflectance, colorimetry, FT-IR and EPR. On the basis of these procedures, we suggest geometrical and structural approximations resulting in an octahedral or distorted octahedral geometry with diverse positions for the metallic centre. According to the EPR spectrum, only one of the complexes may have rhombic symmetry. We also analyzed enthalpy-entropy compensation and the isokinetic effect. In addition, general trends in thermal stability, spectroscopic properties and inclusion in the cavity were analysed. This complete characterization methodology becomes essential for their future application as catalysts.

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Section: Thermogravimetric Analysissupporting

confidence: 79%

Structure characterization of the non-crystalline complexes of copper salts with native cyclodextrins

et al. 2016

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Structural Evidences for the Oxidation of α‐Hydroxycarboxilic Acids to Oxalate Assisted by Copper(II) Ions

Castiñeiras¹,

Balboa²,

Carballo³

et al. 2007

Zeitschrift anorg allge chemie

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The mono-, di-or poly-nuclear copper(II)-oxalate complexes [Cu(phen)(ox)(H 2 O)]·H 2 O (1), {[Cu(µ-ox)(bpy)]·H 2 O· 1/2EtOH} n (2), {[Cu(µ-ox)(bpy)]·2H 2 O} n (3), [{Cu(NO 3 )(bpy)-(H 2 O)} 2 (µ-ox)] (4) and [{Cu(NO 3 )(phen)(H 2 O)} 2 (µ-ox)] (5) (ox ϭ oxalato, phen ϭ 1,10-phenanthroline y bpy ϭ 2,2Ј-bipyridine) were prepared by reacting Cu 2 CO 3 (OH) 2 ·2H 2 O or Cu(NO 3 ) 2 ·3H 2 O salts with glycolic (H 2 GLYO) or lactic (H 2 LACO) acids or D-gluconic acid δ-lactone (δ-gluconolactone, H 2 δ-Glc) in presence of diimine ancillary ligands. Their crystal structures are reported. The copper(II) atom exhibits a 4ϩ1 five-coordinate CuN 2 O 2 OЈ environment in 1, a 4ϩ2 elongated rhombic octahedral CuN 2 O 2 OЈ 2 stereochemistry in 2 or 3, and a 4ϩ1ϩ1 tetragonally elongated octahedral Cu 2 N 2 O 2 OЈOЉ surrounding in 4 or 5. The ligand arrangement and * Prof. Dr. A. Castiñ eiras 717 the packing of 5 seem to be strongly influenced by intra-and intermolecular hydrogen bonding as well as π,π-stacking interactions between C 6 -rings from adjacent phen ligands. The most striking feature now reported is the Cu II -mediated oxidation of GLYO 2Ϫ , LACO 2Ϫ or δ-Glc 2Ϫ leading to the formation of corresponding Cu II -oxalate derivatives. For the glycolate case a mechanism involving a cleavage of the α-C-H bonds is proposed, whereas for lactate or D-gluconate related systems an oxidative degradation through C-C bond cleavage are assumed.

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Nickel(II)-Catalyzed Rearrangements of Free Sugars

Osanai

2001

Topics in Current Chemistry

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C-2 Epimerization of aldoses and ketoses catalyzed by the Ni(II) complex is described. Both epimerization and the preparation of side-chained sugars proceed in the ternary nickel complex through stereospecific rearrangement of the carbon skeleton, that is, from (1-13 C)-D-glucose into (2-13 C)-D-mannose and from (2-13 C)-D-fructose into (2-13 C)-D-hamamelose, and vice versa. The structure of the ligand in the complex plays an important role during the epimerization. The epimerization proceeds more smoothly in both methanolic and aqueous solutions with a more hydrophobic ligand such as N,N¢-higher alkylated ethylenediamine. Due to their ability to self-aggregate in water, the organized metallomicelles can provide an appropriate reaction system for the epimerization of aldoses. The chirality of the ligand contributes to the shift of the equilibrium between the two C-2 epimers.

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Kinetics of the degradative oxidation of sugar-type ligands catalyzed by copper(II) ions

Cited by 11 publications

References 49 publications

Structure characterization of the non-crystalline complexes of copper salts with native cyclodextrins

Structure characterization of the non-crystalline complexes of copper salts with native cyclodextrins

Structural Evidences for the Oxidation of α‐Hydroxycarboxilic Acids to Oxalate Assisted by Copper(II) Ions

Nickel(II)-Catalyzed Rearrangements of Free Sugars

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