Structural NMR and ab Initio Study of Salicylhydroxamic and<i>p</i>-Hydroxybenzohydroxamic Acids:  Evidence for an Extended Aggregation

Garcı́a, Begoña; Secco, Fernando; Ibeas, Saturnino; Muñoz, Asunción; Álvaro, Francisco Javier Hoyuelos; Leal, José M.; Senent, María Luisa; Venturini, Marcella

doi:10.1021/jo0709798

Cited by 23 publications

(16 citation statements)

References 43 publications

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“…The value of pK HL found in water ( pK w HL = 7.6 ± 0.1) is in agreement with the literature data ( pK w HL = 7.56). 24 From the data of Table 1 one obtains pK SDS HL − pK w HL = ΔpK HL = 1.7 as an average value, which is in good accordance with that calculated by using the SDS interfacial potential value at I = 0.2 M. 25 According to the relationship ΔpH = −ΔpK 21,26 one can conclude that the hydrogen ion concentration on the SDS micelles is higher by a factor of about 50 compared to water.…”

Section: Acid Dissociation Equilibriasupporting

confidence: 75%

Mechanism of Ni2+ and NiOH+ interaction with hydroxamic acids in SDS: evaluation of the contributions to the equilibrium and rate parameters in the aqueous and micellar phase

et al. 2012

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The equilibria and kinetics (stopped-flow) of the binding of Ni(II) to salicylhydroxamic acid (SHA) and phenylbenzohydroxamic acid (PBHA) have been investigated in aqueous solutions containing SDS micelles. The two ligands are fairly distributed between the two pseudophases present, so the binding reaction occurs in both phases. The contributions to the total reaction from each phase has been evaluated, following a procedure where use is made of the experimentally determined partition coefficients of the reactants involved. The mechanism of the reaction occurring on the micelle surface has been derived and comparison with the mechanism in water shows that the step Ni(2+) + HL ⇄ NiHL(2+) is operative in both pseudophases, whereas the step Ni(2+) + L(-)⇄ NiL(+), which is operative in water, is replaced in SDS by the step NiOH(+) + HL ⇄ NiL(+). The analysis of the equilibrium and of the kinetic data enabled the evaluation of the equilibrium and the rate constants of the individual steps taking part in the binding process over the micelle surface. Interestingly, the first hydrolysis constant of the Ni(H(2)O)(6)(2+) ion in SDS is more than two orders of magnitude higher than in water. The agreement between the equilibrium constants derived from kinetics and those obtained by static measurements confirms the validity of the proposed mechanism.

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Section: Acid Dissociation Equilibriasupporting

confidence: 75%

Mechanism of Ni2+ and NiOH+ interaction with hydroxamic acids in SDS: evaluation of the contributions to the equilibrium and rate parameters in the aqueous and micellar phase

et al. 2012

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“…The peak assignments for protons A , and B were made based on the previous reports (Garcia et al, (2007).…”

Section: Figurementioning

confidence: 99%

Assembling Ligands In Situ Using Bioorthogonal Boronate Ester Synthesis

Shin

Almeida

Gerona‐Navarro

et al. 2010

Chemistry & Biology

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SUMMARY Many molecules that could manipulate cellular function are not practical due to their large size and concomitant undesirable pharmocokinetic properties. Here we describe a bioorthogonal, highly stable boronate ester (HiSBE) synthesis and use this reaction to synthesize a bioogically active molecule from smaller precursors in a physiological context. The rapid rate of HiSBE synthesis suggests that it may be useful for assembling a wide variety of biologically active molecules in physiological solutions.

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“…Scheme presents the possible neutral and anionic structures of salicylhydroxamic acid. The SHA' most stable gas‐phase conformer is an A‐Z amide, a structure with all three phenolate, carboxylate, and hydroxamate oxygen in the cis position . The NOH functional group is reactive α‐nucleophile.…”

Section: Resultsmentioning

confidence: 99%

O‐Nucleophilicity of Hydroxamate Ions for Cleavage of Carboxylate and Phosphate Esters in Cationic Micelles

Satnami

Karbhal

Dewangan

2014

Int J of Chemical Kinetics

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The nucleophilic reactivities of hydroxamate (HA−) ions of the structure RCONHO− [R = CH3 (acetohydroxamate, AHA−), C6H5 (benzohydroxamate, BHA−), 2‐OHC6H4 (salicylhydroxamate, SHA−), and 4‐CH3OC6H4 (4‐methoxbenzohydroxamate, MBHA−)] for the hydrolysis of p‐nitrophenyl benzoate (PNPB), tris(3‐nitrophenyl) phosphate (TRIS), and bis(2,4‐dinitrophenyl) phosphate (BDNPP) have been examined kinetically. Over the pH range of 6.7–11.4, the α‐nucleophile (HA−) accelerates deacylation of PNPB and dephosphorylation of TRIS (in cetyltrimethylammonium bromide (CTAB) micelle, 2.0 × 10−3 M). The salicylhydroxamate ion encountered effective catalysis than AHA−, BHA−, and MBHA− ions. The monoanionic SHA− and dianionic SA2− forms of salicylhydroxamic acid are the reactive species. The hydroxamic acid concentration–dependent critical micelle concentration (cmc) and fractional ionization constant (α) and of CTAB provide qualitative information for the micellar incorporation of the hydroxamate ion. The ab initio calculations performed on the hydroxamate ions at restricted Hartree–Fock using the 6‐311G (d,p) basis set revealed the O‐nucleophilicity of hydroxamate ions toward C=O and P=O centers. On the basis of ab initio calculation, it has been concluded that hydroxamic acids can exist into E‐amide and Z‐amide forms. The large stable amide or imide anions of hydroxamate are strong nucleophilic for the esterolytic cleavage of carboxylate and phosphate esters.

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Structural NMR and ab Initio Study of Salicylhydroxamic andp-Hydroxybenzohydroxamic Acids: Evidence for an Extended Aggregation

Cited by 23 publications

References 43 publications

Mechanism of Ni2+ and NiOH+ interaction with hydroxamic acids in SDS: evaluation of the contributions to the equilibrium and rate parameters in the aqueous and micellar phase

Mechanism of Ni2+ and NiOH+ interaction with hydroxamic acids in SDS: evaluation of the contributions to the equilibrium and rate parameters in the aqueous and micellar phase

Assembling Ligands In Situ Using Bioorthogonal Boronate Ester Synthesis

O‐Nucleophilicity of Hydroxamate Ions for Cleavage of Carboxylate and Phosphate Esters in Cationic Micelles

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