lobna.nassr

Lobna Abdel-Mohsen Ebaid Nassr

Professor - Director of Quality Management Unit - Faculty of Science - Sohag University

Faculty of science

Address: Chemistry Department - Faculty of Science - Sohag University

31

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DNA binding ability mode, spectroscopic studies, hydrophobicity, and in vitro antibacterial evaluation of some new Fe(II) complexes bearing ONO donors amino acid Schiff bases
New series of Fe(II) complexes and Schiff base amino acids have been designed and synthesized from the bioactive ligands by condensation of 5-bromo-2-hydroxybenzaldehyde and aamino acids (L-alanine (ala), L-phenylalanine (phala), L-aspartic acid (aspa), L-histidine (his) and L-arginine (arg)). Elemental analyses, infrared, ultraviolet–visible spectra, as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure of the newly ... Read more

Kinetics, reactivity, initial-transition state analysis and thermodynamic parameters of base catalyzed hydrolysis of coumalic acid in solvents with different polarities
Base-catalyzed hydrolysis of coumalic acid (COU) in binary aqueous-methanol and aqueous-acetone mixtures has been studied kinetically at a temperature range from 283 to 313 K Moreover, the change in the activation energy barrier of COU from water to water–methanol and water–acetone mixtures is estimated from the kinetic data. Solvent effects on reactivity trends have been analyzed into initial and transition ... Read more

Reactivity trends of hydroxide ion attack on high spin Fe(II) complexes including bromosalcylidene amino acid ligands in some mixed aqueous solvents: Gibb’s free energy of transfer and initial-transition state analysis
The kinetics of hydroxide ion attack on bis(bromosalicylidene alanate)iron (II) (bsali), bis(bromosalicylidene phenylalanate)iron(II) (bsphali), bis(bromosalicylidene aspartate)iron(II) (bsasi), (bromosalicylidene histidinate)iron(II) (bshi), bis(bromosalicylidene arginate)iron(II) (bsari) have been reported in different binary aqueous solvent mixtures at 298 K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic forms of the complexes investigated, as well as the transfer chemical potentials ... Read more

Hydrophobicity, reactivity trends of base catalyzed hydrolysis of some novel high spin Fe(II) Schiff base amino acid chelates in some binary aqueous solvent mixtures: Initial-transition state analysis
Rate constants for the base hydrolysis of bis(naphthylidene alanate)iron (II) (nali), bis (naphthylidene phenylalanate)iron(II) (nphali), bis(naphthylidene aspartate)iron(II) (nasi) (naphthylidene histidinate)iron(II) (nhi), bis(naphthylidene arginate)iron(II) (nari) have been reported in different binary aqueous solvent mixtures at 298 K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic forms of the complexes investigated, as well as the transfer chemical ... Read more

Synthesis of novel coumarin derivatives based on 6-aminocoumarin, kinetics inspection of base hydrolysis, and spectrophotometric tracer of intermediate progress
The kinetics of the base hydrolysis of 6-aminocoumarin and some of its derivatives was studied spectrophotometrically in aqueous medium at 298 K under pseudo-firstorder conditions ([OH-][[[Compound]). The suggested general rate equation can be given as: rate = {k1 ? k2 [OH-]} [complex]. The reasonable mechanism suggested that the investigated reaction proceeded via the formation of an intermediate and the ring ... Read more

Reactivity tracers of the hydrolysis of Fe(II)-bis(salicylidene) complexes: Initial -transition states analysis and enhanced impact of tensides on the kinetic trends
The kinetics of the acid hydrolysis reaction of Fe(II)-bis(salicylidene) complexes were followed under pseudo–first-order conditions ([H+] >> [complex]) at 298 K. The ligands of the studied azomethine complexes were derived from the condensation of salicylaldehyde with different five α-amino acids. The hydrolysis reactions were studied in acidic medium at different ratios (v/v) of aqua–organic mixtures. The decrease in the dielectric ... Read more

Tailoring, physicochemical characterization, antibacterial and DNA binding mode studies of  Cu(II) Schiff bases amino acid bioactive agents incorporating 5- bromo-2-hydroxybenzaldhyde
Five novel Cu(II) complexes derived from the condensation between 5-bromosalicylaldehyde (bs) and α-amino acids (L-alanine, L-phenylalanine, L-aspartic acid, L-histidine and L-arginine) were synthesized and characterized by their elemental analyses, thermogravimetric analysis, IR, mass and electronic spectra, conductance and magnetic measurements. Moreover, the stoichiometry and the stability constants of the prepared complexes have been determined spectrophotometrically using continuous variation and molar ... Read more

2015 | Keywords Hydrophobic, Surfactant, alkali halide,
Kinetic screening for the acid-catalyzed hydrolysis of some hydrophobic Fe(II) Schiff base amino acid chelates and reactivity trends in the presence of alkali halide and surfactant
Kinetics of acid-catalyzed hydrolysis of some high-spin Fe(II) Schiff base amino acid complexes were followed spectrophotometrically at 298 K under pseudo–first-order conditions. The studied ligands were derived from the condensation of 5-bromosalicylaldehyde with different four amino acids (phenylalanine, aspartic acid, histidine, and arginine). The acid hydrolysis reaction was studied in aqueous media and in the presence of different concentrations of ... Read more

Kinetics of acid hydrolysis and reactivity of some antibacterial hydrophilic Iron(II) imino-complexes
Kinetic study of acid hydrolysis of some hydrophilic Fe(II) Schiff base amino acid complexes with antibacterial properties was performed using spectrophotometry. The Schiff base ligands were derived from sodium 2-hydroxybenzaldehyde-5-sulfonate and glycine, L-alanine, L-leucine, L-isoleucine, DL-methionine DL-serine, or L-phenylalanine. The reaction was studied in aqueous media under conditions of pseudo-first order kinetics. Moreover, the acid hydrolysis was studied at different ... Read more

Hydrophobicity and kinetic inspection of hydroxide ion attack on some chromen-2-one laser dyes in binary aqueous–methanol and aqueous–acetone mixtures: Initial state-transition state analysis
In the present study, reactivity base-catalyzed hydrolysis of 7-dimethylamino-4-methyl- 2H-chromen-2-one (DMAC) and 7-diethylamino-4-methyl-2H-chromen-2-one (DEAC) in binary aqueous–methanol and aqueous–acetone mixtures was examined at 298 K. Kinetic results, rate laws and reaction mechanisms were established. Moreover, the change in the activation energy barrier of the investigated compounds from water to water–methanol and water–acetone mixtures was estimated from the kinetic data. Base-catalyzed ... Read more