A new octahedral cobalt(III) complex of (1,8)-bis(2-hydroxybenzamido)-3,6-diazaoctane incorporating phenolate-amide-amine coordination: synthesis, X-ray crystal structure, ligand substitution and redox activity with sulfur(IV) and l-ascorbic acid

Nayak, Suprava; Dash, Anadi C.; Lahiri, Gautam K.

doi:10.1007/s11243-007-9012-4

Cited by 5 publications

(3 citation statements)

References 45 publications

(31 reference statements)

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“…5,6 We have been working on the solution state kinetics and equilibria involving polydentate phenol-amide ligands and transition metal ions * For correspondence with a view to understand the mechanism of binary and ternary complex formation and electron transfer processes. 7 As a part of this program we felt it worthwhile to investigate the kinetics of acid and base hydrolysis of such polydentate amide ligands.…”

Section: Introductionmentioning

confidence: 99%

Proximity effect on the general base catalysed hydrolysis of amide linkage: The role of cationic surfactant, CTABr

Dash

2011

J Chem Sci

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The bis phenoxide forms of (1,2)bis(2-hydroxybenzamido)ethane(I), (1,5)bis(2-hydroxybenzamido)3-azapentane(II), (1,3)bis(2-hydroxybenzamido)propane(III), and (1,8)bis(2-hydroxybenzamido)3,6-diazaoctane(IV) undergo facile hydrolysis of one of the amide groups (0.02The reactivity trend follows I ∼ II >> III ∼ IV with low activation enthalpy {25.7 ± 2.8 ≤ H = (kJ mol −1 ) ≤ 64.8 ± 7.0}. The high negative and comparable values of activation entropy{−234 ±8 ≤ S = (J K −1 mol −1 ) ≤ −127 ± 20} are consistent with closely similar, and ordered transition states which can be assembled by favourably oriented phenoxide groups. The solvent kinetic isotope effect for I, k H2O /k D2O+H2O ∼ 1 (20 and 50 volume% D 2 O), indicates that proton transfer is not involved as a part of the rate controlling process. The observed slowing down of the rate of this reaction for I in the micellar pseudo phase of CTABr also supports the proposed mechanism. Under premicellar conditions, however, rate acceleration is observed, a consequence believed to be associated with the capping effect of the hydrophobic tail of the surfactant cation forming the reactive ion-pair, CTA + , (I-2H) 2− exclusively in the aqueous pseudo phase.

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Section: Introductionmentioning

confidence: 99%

Proximity effect on the general base catalysed hydrolysis of amide linkage: The role of cationic surfactant, CTABr

Dash

2011

J Chem Sci

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“…Attention has been focused on the copper(II), [11][12][13][14][15][16] nickel(II), [13,16,17] cobalt(II), [18] cobalt(III), [19][20][21] cobalt(IV), [22] iron(II), [23][24][25] iron(III), [23,[25][26][27][28] manganese(III), [29][30][31][32] manganese(IV), [33] chromium(III), [26,34] oxovanadium(IV), [35,36] oxovanadium(V), [36] ruthenium(IV), [37] nitridoruthenium(VI), [38] osmium(III), [39] osmium(IV), [40,41] and nitridoosmium(VI) [38] complexes with ligands containing two 2-hydroxybenzamido moieties. Some of these metal complexes exhibit interesting redox, catalytic, spectral, and magnetic properties.…”

Section: Introductionmentioning

confidence: 99%

Structure and Properties of Copper(II), Manganese(III), and Iron(III) Complexes with Potentially Pentaanionic Heptadentate Ligands Including Alkoxido, Amido, and Phenoxido Donors

et al. 2009

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The synthesis and characterization of copper(II), manganese(III), and iron(III) complexes [Cu2(L1)(OAc)Cs2(MeOH)2]n (1), [Mn2(H3L1)2(OMe)2]·2MeOH (2), [Fe2(H3L1)2(Hpz)4](ClO4)2·2CH3CN (3), and [Fe2(H3L3)2(OMe)2]·8MeOH (4) of potentially pentaanionic heptadentate ligands,2‐hydroxy‐N‐{2‐hydroxy‐3‐[(2‐hydroxybenzoyl)amino]propyl}benzamide (H5L1) and 2‐hydroxy‐N‐{3‐hydroxy‐5‐[(2‐hydroxybenzoyl)amino]pentyl}benzamide (H5L3), are reported. The crystal structure and magnetic properties of these complexes have been determined. In complex 1, the ligand H5L1 acts as a heptadentate, fully deprotonated ligand, [L1]5–. In complexes 2, 3, and 4, H5L1 (2, 3) and H5L3 (4) act as tetradentate, partially deprotonated ligands, [H3L1]2– and [H3L3]2–.In complex 1, anionic [Cu2(L1)(OAc)]2– and cationic [Cs(MeOH)]+ units are linked through a quadruply bridging acetate ion and through the phenoxido‐oxygen and amido‐oxygen donor atoms of [L1]5– to yield a 2D polymeric network. Complexes 2–4 form extended supramolecular networks. Magnetic susceptibility data evidence antiferromagnetic interactions for 1, 2, and 4. The Fe···Fe distance is too long to allow measurable magnetic interactions in complex 3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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INTRODUCTIONSynthesis and isolation of multidentate carboxamido ligand containing N4O2 donor atoms in the form of amide, amine and phenolate groups have remained a long standing challenge [1][2][3][4][5][6] owing to their varied functionality during complexation. These ligands have proved to be excellent complexing agents for several metal ions such as Mn III/II [6], Fe III/II [7-10], Cr III [11], Co III/II [12][13][14] and Cu II [15], etc.

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confidence: 99%

Synthesis and Characterization of Cobalt(III) Complex of 1,5-bis(2-Hydroxybenzamido)-3- aza pentane and its Interaction with Glutathione: A Kinetic and Spectrophotometric Study

Aravind

Brahma

Nayak³

2019

Asian J. Chem.

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A new octahedral cobalt(III) complex of 1,5-bis(2-hydroxybenzamido)-3-aza pentane was synthesized and characterized by elemental analysis, UV-visible, IR, mass spectrometry and thermal analysis methods. Oxidative behaviour of the complex towards the physiologically abundant tripeptide, glutathione(GSH) was studied by UV-visible and FT-NMR techniques. Kinetics of electron transfer between the complex and GSH was studied at 25.0 ≤ t/°C ≤ 45.0, 0.025 ≤ [H+]/mol dm-3 ≤ 0.20 and I = 1.0 mol dm-3 (NaClO4). NMR spectra of the reaction mixture were taken as a function of time. Changes observed in the NMR-spectrum during the period of scanning are the initial disappearance of the fine structure and subsequent broadening of the signals of GSH protons. Peaks at (δ, ppm): 2.93 and 2.98, characteristics of Cys-CH2 δ protons in GSH get disappear slowly and new peaks develop at (δ, ppm): 3.33 and 3.38, corresponding to resonating frequencies of Cys-CH2 δ protons in GSSG. Likewise, the peak at (δ, ppm):2.93, characteristic of Cys-CH2 δ proton in GSH is replaced by the resurgence of two peaks at (δ, ppm): 4.3 and 4.1 ppm, commensurate with the resonating frequencies of same set of protons as that of GSH but in a dimeric environment. The time dependent NMR simulation of the reaction reveals that GSH reduces the CoIII moiety successfully, while it gets converted into the dimer, GSSG. The relatively fast transformation of GSH to GSSG as evident from both electronic spectra and NMR studies together with the activation parameters obtained from the temperature dependence of reaction rate suggest that there is no involvement of any bridging group for electron transfer and the redox process may be taking place via outer sphere mechanism.

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A new octahedral cobalt(III) complex of (1,8)-bis(2-hydroxybenzamido)-3,6-diazaoctane incorporating phenolate-amide-amine coordination: synthesis, X-ray crystal structure, ligand substitution and redox activity with sulfur(IV) and l-ascorbic acid

Cited by 5 publications

References 45 publications

Proximity effect on the general base catalysed hydrolysis of amide linkage: The role of cationic surfactant, CTABr

Proximity effect on the general base catalysed hydrolysis of amide linkage: The role of cationic surfactant, CTABr

Structure and Properties of Copper(II), Manganese(III), and Iron(III) Complexes with Potentially Pentaanionic Heptadentate Ligands Including Alkoxido, Amido, and Phenoxido Donors

Synthesis and Characterization of Cobalt(III) Complex of 1,5-bis(2-Hydroxybenzamido)-3- aza pentane and its Interaction with Glutathione: A Kinetic and Spectrophotometric Study

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