The complexing properties of oxalodihydrazide, acethydrazide and formic hydrazide with Cu(II) in aqueous solution

Woźniczka, Magdalena; Szajdzińska‐Piętek, Ewa; Jezierska, Julia; Pasternak, Beata; Gądek-Sobczyńska, Joanna; Kufelnicki, Aleksander

doi:10.1016/j.ica.2016.04.041

Cited by 9 publications

(6 citation statements)

References 47 publications

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“…However, the previous study did not consider the formation of the protonated species. The value of log β 111 = 14.57, reported for formic hydrazide, 26 is in good agreement with our value of 13.77.…”

Section: Potentiometrysupporting

confidence: 91%

“…They are close to the pK a values of pyridine (3.8) and hydrazide (10.8), 25 and lower than that of acetyl hydrazide (11.86). 26 Figure 1 shows the complex formation (Z M -bar), and Figure 2 shows the deprotonation (Q M -bar) curves for the Cu(II), Ni(II) and Zn(II)-ISO systems. In the Cu(II)-ISO system, neither the Z M -bar function nor the Q M -bar function starts at zero in the acidic solution, indicating that some complexation had already taken place at the start of the titration.…”

Section: Potentiometrymentioning

confidence: 99%

“…The coloured solid lines are theoretical, calculated using the models given in Table 1 RESEARCH ARTICLE DK Tolulope, GE Jackson, MR Caira and N Hammouda 68 S Afr J Chem, 2022, 76, 65-71 https://journals.co.za/content/journal/chem/ pH 3.53 and 2.14-2.48, respectively. 26 For Ni(II), classic formation functions were obtained. The hump at -log[L] =10 indicates the presence of a protonated species, while the fanning back at -log[L] = 4.9 indicates hydroxy species formation.…”

Section: Potentiometrymentioning

confidence: 99%

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Potentiometrie and spectroscopic study of isoniazid - an anti-tubercular drug

Tolulope¹,

Jackson²,

Caira³

et al. 2022

S.Afr.j.chem.

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The copper, nickel and zinc complexes of isoniazid (ISO, isonicotinic acid hydrazide), an anti-tubercular drug, have been investigated to determine whether these metal-ions improve the permeability and bioavailability of the drug. Since such properties of isonazid depend on its solution speciation, the latter was investigated by determining the equilibrium constants for the reaction of H+, Cu(II), Ni(II) and Zn(II) with isonazid in aqueous solution at 25.00 ± 0.01 °C and 0.15 M (NaCl), using glass electrode potentiometry. The structure of the copper complex of isoniazid was investigated using ultraviolet-visible spectroscopy. The results support the structures postulated from the potentiometric data. This study also considered membrane permeability using a Franz cell and octanol/water distribution coefficients. Distribution coefficient studies showed that ISO and its metal complexes are hydrophilic. The incorporation of a metal-ion improves the hydrophilicity of the ligand. The presence of a metal ion greatly enhanced the permeation of ISO through an artificial membrane in the order Cu(II) > Ni(II) > Zn(II) > ISO at pH 2 and Zn(II) > Ni(II) > ISO > Cu(II) at pH 4.

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Section: Potentiometrysupporting

confidence: 91%

Section: Potentiometrymentioning

confidence: 99%

Section: Potentiometrymentioning

confidence: 99%

See 1 more Smart Citation

Potentiometrie and spectroscopic study of isoniazid - an anti-tubercular drug

Tolulope¹,

Jackson²,

Caira³

et al. 2022

S.Afr.j.chem.

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“…The concentration formation constants were calculated by the Hyperquad 2013 fitting procedure according to the formula: β mlh = [M m L l H h ]/[M] m [L] l [H] h [ 61 , 62 ]. The ionic product of water p K w = 13.77 [ 63 ] was included in the equilibrium model.…”

Section: Methodsmentioning

confidence: 99%

Equilibria in Aqueous Cobalt(II)—Reduced Schiff Base N-(2-hydroxybenzyl)alanine System: Chemical Characterization, Kinetic Analysis, Antimicrobial and Cytotoxic Properties

et al. 2020

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The present study describes the coordination properties of a reduced Schiff base, N-(2-hydroxybenzyl)alanine, towards cobalt(II) using potentiometric as well as spectroscopic (UV-Vis and ESI-MS) methods. The results indicate the formation of six mononuclear complexes showing high stability in aqueous solution. Coordination occurs in the {O−phenolic,N,O−carboxyl} and {N,O−carboxyl} chelation modes, depending on the degree of ligand deprotonation. Examination of the complexation equilibria at pH ca 7, which is important from a biological point of view, allowed to identify two species: [CoL] and [CoL2H]−. The kinetic analysis showed a structural change of those cobalt(II) complexes from octahedral to tetrahedral in accordance with a first-order time relationship. The antimicrobial properties of N-(2-hydroxybenzyl)alanine, cobalt(II) nitrate and of the Co(II) – ligand complexes were determined against Gram-positive bacteria (Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis), Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Helicobacter pylori) and a fungal strain (Candida). The results indicate that the complexes are more active for more strains than the ligand alone. Nevertheless, the complexes induce a higher decrease in the metabolic activity of cells but without damage to nuclei. Tetrahedral structures show stronger anti-cellular toxicity than octahedral complexes, which is most likely due to the higher accessibility of the cobalt(II) center.

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“…The overall concentration formation constants were calculated using the Hyperquad 2013 fitting procedure according to the formula: β mlh = [M m L l H h ]/[M] m [L] l [H] h [40] , [41] . The species distribution curves were simulated as a function of pH in HySS 2009 [42] .…”

Section: Methodsmentioning

confidence: 99%