Ismail A Ajaj - Academia.edu (original) (raw)
Papers by Ismail A Ajaj
Al-Mukhtar Journal of Sciences
Henna is widely used by Libyan women as a cosmetic, which may contain lead (pb), cadmium (Cd) and... more Henna is widely used by Libyan women as a cosmetic, which may contain lead (pb), cadmium (Cd) and other toxic heavy metals. The purpose of this study was to determine heavy metal content of seven henna products, imported and locally produced in Zliten, Libya. An analytical method was performed using Atomic Absorption Spectrophotometer (AAS). In terms of heavy metal content determination, the results revealed a significant difference between henna leaves and cosmetic henna samples. The premixed henna sample H2 had the highest heavy metal concentrations with a high level of lead (6.952ppm), exceeding the WHO's maximum limit and the (ASEAN) Guidelines on Limits of Contaminants for Cosmetics Heavy metal maximum limits, Lead (Pb) is 1 ppm. Nickel (Ni) levels in (H4=5.201ppm) and (H6=2.023ppm ) henna samples were found to be above the WHO's limit of 1.68ppm. The results indicated that such cosmetics expose consumers to high levels of Pb and Cu, and hence to potential health ris...
In this work, a simple and convenient synthesis of tautomeric (6 or 2)-hydroxy-4-methyl-(2 or 6)-... more In this work, a simple and convenient synthesis of tautomeric (6 or 2)-hydroxy-4-methyl-(2 or 6)-oxo-1-(substituted phenyl)-(1,2 or 1,6)-dihydro- pyridine-3-carbonitriles from ethyl acetoacetate and 2-cyano-N-(substituted phenyl)-ethanamides using microwave assisted chemistry is presented. The structure of the obtained product was confirmed by the use of FTIR, NMR, UV and MS techniques. Presence of tautomeric forms, 6-hydroxy-4-methyl-2-oxo-1-(substituted phenyl)-1,2-dihydropyridine-3-carbonitriles and 2-hydroxy-4-methyl -6-oxo-1-(substituted phenyl)-1,6-dihydropyridine-3-carbonitriles, and state of equilibrium in DMSO-d6 of the obtained product was studied by 1H and 13C NMR spectroscopy, as well as B3LYP/6-311++G(d,p) and GIAO/WP04/aug-cc-pVDZ theoretical calculations. Tautomeric equilibria of title compounds were quantitatively analyzed by UV/Vis spectroscopy and theoretical approaches. Kamlet-Taft and Catalán correlation analysis were done. The LFER correlation results showed sig...
The study identifies the nitrate (NO3) and nitrite (NO2) content in leafy vegetables (parsley, ch... more The study identifies the nitrate (NO3) and nitrite (NO2) content in leafy vegetables (parsley, chard, coriander) in three agricultural areas in Zliten (Azdo, Dafniya, Madjer) using the colorimeter dr / 980 device, and assesses whether the content is within the comparatively with allowable concentrations. The results obtained from this study show that the nitrate concentrations in all samples examined are within the global standards, with the highest level of 5.5 ppm found in chard samples collected from the area of Azdo. As for nitrite, the concentrations found in the studied samples are higher than nitrate concentrations. Overall, the nitrate and nitrite content are found to be within the permitted concentrations based on international standards, where the highest concentration of nitrite of 60 ppm is recorded in parsley samples from the Dafniya area.
This work was to study batch biosorption of Cd (II) ions from aqueous solution by Powdered Seagra... more This work was to study batch biosorption of Cd (II) ions from aqueous solution by Powdered Seagrasses (PSG). The optimum conditions for the adsorption of Cd (II) ions from aqueous solution by seagrasses were investigated by considering the extent of adsorption with respect to contact time, initial metal ion concentration and temperature. The results obtained indicates that the extent of metal ions removed decreases with increasing contact adsorption equilibrium data best fitted Freundlich adsorption isotherm. Thermodynamic study indicated that the adsorption of Cd (II) ions onto seagrasses was spontaneous and endothermic in nature.
![Research paper thumbnail of Experimental and theoretical study on solvent and substituent effects on the intramolecular charge transfer in 3-[(4-substituted)phenylamino]isobenzofuran-1(3H)-ones](https://attachments.academia-assets.com/87602179/thumbnails/1.jpg)
](Journal of the Serbian Chemical Society, 2018
The substituent and solvent effects on solvatochromism in 3-[(4-substituted) phenylamino]isobenzo... more The substituent and solvent effects on solvatochromism in 3-[(4-substituted) phenylamino]isobenzofuran-1(3H)-ones were studied using experimental and theoretical methodologies. The effect of specific and non-specific solvent?solute interactions on the shifts of UV?Vis absorption maxima were evaluated using the Kamlet?Taft and Catal?n solvent parameter sets. The experimental results were studied by density functional theory (DT) and time-dependent density functional theory (TD-DFT). The HOMO/LUMO energies (EHOMO/ELUMO) and energy gap (Egap) values, as well as the mechanism of electronic excitations and the changes in the electron density distribution in both ground and excited states of the investigated molecules were studied by calculation in the gas phase. The electronic excitations were calculated by the TD-DFT method in the solvent methanol. It was found that both substituents and solvents influence the degree of ?-electron conjugation of the synthesized molecules and affect the ...
Arabian Journal of Chemistry, 2015
The state of the tautomeric equilibria of eleven arylazo pyridone dyes was evaluated from UV-Vis ... more The state of the tautomeric equilibria of eleven arylazo pyridone dyes was evaluated from UV-Vis absorption spectra with the aid of the quantum mechanical modeling. NMR analysis and theoretical calculations, by using PCM/xB97X-D/6-311G(d,p) method, confirmed that prepared compounds exist mainly in Hydrazo form. Internal hydrogen bonding in Hydrazo tautomer, analyzed by AIM topological analysis and total electron density at the bond critical point (BCP), confirmed a presence of strong hydrogen bond which contributes to higher stability of Hydrazo form. Linear solvation energy relationships (LSERs) rationalized solvent influence on solvatochromism of all compounds in Hydrazo form and K T by using Kamlet-Taft model. Linear free energy relationships (LFERs) were applied to the substituent-induced NMR chemical shifts (SCS) using SSP (single substituent parameter) and DSP (dual substituent parameter) model. Density plots over the highest occupied (HOMO) and lowest unoccupied molecular orbitals (LUMO) energy surface provide information on the charge transfer during excitation. The molecular electrostatic potential (MEP)
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
h i g h l i g h t s The tautomeric equilibria of title molecules are investigated experimentally ... more h i g h l i g h t s The tautomeric equilibria of title molecules are investigated experimentally and theoretically. Influence of solvent and substituent on UV-vis absorption spectra was examined. K T values of the investigated compounds were determined. ICT process was deduced from Bader's analysis.
Structural Chemistry, 2014
ABSTRACT The tautomeric equilibria between 2-pyridone and 2-hydroxypyridine forms of methoxy, chl... more ABSTRACT The tautomeric equilibria between 2-pyridone and 2-hydroxypyridine forms of methoxy, chloro, and nitro derivatives of 3-cyano-4-(2-, 3-, and 4-substituted phenyl)-6-phenyl-2(1H)-pyridones were evaluated from UV/Vis spectral data. Linear solvation energy relationships of Kamlet–Taft and Catalán-rationalized solvent have influence on tautomeric equilibria. Transmission of substituent effect was analyzed by the Hammett equation. Quantum chemical calculations were performed by density functional theory (B3LYP). The experimental data were interpreted with the aid of time-dependent density functional method. Electron density distribution was analyzed by Bader’s analysis. It was found that substituents of different electronic properties change the extent of conjugation, and affect intramolecular charge transfer character. Theoretical calculations and experimental results gave insight into the influence of the molecular conformation on the transmission of substituent effects, as well as on contribution of different solvent–solute interactions.
HETEROCYCLES, 2008
ABSTRACT
![Research paper thumbnail of Experimental and theoretical study on solvent and substituent effects on the intramolecular charge transfer in 3-[(4-substituted)phenylamino]isobenzofuran-1(3H)-ones](https://attachments.academia-assets.com/82333564/thumbnails/1.jpg)
](Journal of the Serbian Chemical Society
The substituent and solvent effects on solvatochromism in 3-[(4-substituted)phenylamino]isobenzof... more The substituent and solvent effects on solvatochromism in 3-[(4-substituted)phenylamino]isobenzofuran-1(3H)-ones were studied using experimental and theoretical methodologies. The effect of specific and non-specific solvent-solute interactions on the shifts of UV-Vis absorption maxima were evaluated using the Kamlet-Taft and Catalán solvent parameter sets. The experimental results were studied by density functional theory (DT) and time-dependent density functional theory (TD-DFT). The HOMO/LUMO energies (E HOMO /E LUMO) and energy gap (E gap) values, as well as the mechanism of electronic excitations and the changes in the electron density distribution in both ground and excited states of the investigated molecules were studied by calculation in the gas phase. The electronic excitations were calculated by the TD-DFT method in the solvent methanol. It was found that both substituents and solvents influence the degree of π-electron conjugation of the synthesized molecules and affect the intramolecular charge transfer character.
Al-Mukhtar Journal of Sciences
Henna is widely used by Libyan women as a cosmetic, which may contain lead (pb), cadmium (Cd) and... more Henna is widely used by Libyan women as a cosmetic, which may contain lead (pb), cadmium (Cd) and other toxic heavy metals. The purpose of this study was to determine heavy metal content of seven henna products, imported and locally produced in Zliten, Libya. An analytical method was performed using Atomic Absorption Spectrophotometer (AAS). In terms of heavy metal content determination, the results revealed a significant difference between henna leaves and cosmetic henna samples. The premixed henna sample H2 had the highest heavy metal concentrations with a high level of lead (6.952ppm), exceeding the WHO's maximum limit and the (ASEAN) Guidelines on Limits of Contaminants for Cosmetics Heavy metal maximum limits, Lead (Pb) is 1 ppm. Nickel (Ni) levels in (H4=5.201ppm) and (H6=2.023ppm ) henna samples were found to be above the WHO's limit of 1.68ppm. The results indicated that such cosmetics expose consumers to high levels of Pb and Cu, and hence to potential health ris...
In this work, a simple and convenient synthesis of tautomeric (6 or 2)-hydroxy-4-methyl-(2 or 6)-... more In this work, a simple and convenient synthesis of tautomeric (6 or 2)-hydroxy-4-methyl-(2 or 6)-oxo-1-(substituted phenyl)-(1,2 or 1,6)-dihydro- pyridine-3-carbonitriles from ethyl acetoacetate and 2-cyano-N-(substituted phenyl)-ethanamides using microwave assisted chemistry is presented. The structure of the obtained product was confirmed by the use of FTIR, NMR, UV and MS techniques. Presence of tautomeric forms, 6-hydroxy-4-methyl-2-oxo-1-(substituted phenyl)-1,2-dihydropyridine-3-carbonitriles and 2-hydroxy-4-methyl -6-oxo-1-(substituted phenyl)-1,6-dihydropyridine-3-carbonitriles, and state of equilibrium in DMSO-d6 of the obtained product was studied by 1H and 13C NMR spectroscopy, as well as B3LYP/6-311++G(d,p) and GIAO/WP04/aug-cc-pVDZ theoretical calculations. Tautomeric equilibria of title compounds were quantitatively analyzed by UV/Vis spectroscopy and theoretical approaches. Kamlet-Taft and Catalán correlation analysis were done. The LFER correlation results showed sig...
The study identifies the nitrate (NO3) and nitrite (NO2) content in leafy vegetables (parsley, ch... more The study identifies the nitrate (NO3) and nitrite (NO2) content in leafy vegetables (parsley, chard, coriander) in three agricultural areas in Zliten (Azdo, Dafniya, Madjer) using the colorimeter dr / 980 device, and assesses whether the content is within the comparatively with allowable concentrations. The results obtained from this study show that the nitrate concentrations in all samples examined are within the global standards, with the highest level of 5.5 ppm found in chard samples collected from the area of Azdo. As for nitrite, the concentrations found in the studied samples are higher than nitrate concentrations. Overall, the nitrate and nitrite content are found to be within the permitted concentrations based on international standards, where the highest concentration of nitrite of 60 ppm is recorded in parsley samples from the Dafniya area.
This work was to study batch biosorption of Cd (II) ions from aqueous solution by Powdered Seagra... more This work was to study batch biosorption of Cd (II) ions from aqueous solution by Powdered Seagrasses (PSG). The optimum conditions for the adsorption of Cd (II) ions from aqueous solution by seagrasses were investigated by considering the extent of adsorption with respect to contact time, initial metal ion concentration and temperature. The results obtained indicates that the extent of metal ions removed decreases with increasing contact adsorption equilibrium data best fitted Freundlich adsorption isotherm. Thermodynamic study indicated that the adsorption of Cd (II) ions onto seagrasses was spontaneous and endothermic in nature.
Journal of the Serbian Chemical Society, 2018
The substituent and solvent effects on solvatochromism in 3-[(4-substituted) phenylamino]isobenzo... more The substituent and solvent effects on solvatochromism in 3-[(4-substituted) phenylamino]isobenzofuran-1(3H)-ones were studied using experimental and theoretical methodologies. The effect of specific and non-specific solvent?solute interactions on the shifts of UV?Vis absorption maxima were evaluated using the Kamlet?Taft and Catal?n solvent parameter sets. The experimental results were studied by density functional theory (DT) and time-dependent density functional theory (TD-DFT). The HOMO/LUMO energies (EHOMO/ELUMO) and energy gap (Egap) values, as well as the mechanism of electronic excitations and the changes in the electron density distribution in both ground and excited states of the investigated molecules were studied by calculation in the gas phase. The electronic excitations were calculated by the TD-DFT method in the solvent methanol. It was found that both substituents and solvents influence the degree of ?-electron conjugation of the synthesized molecules and affect the ...
Arabian Journal of Chemistry, 2015
The state of the tautomeric equilibria of eleven arylazo pyridone dyes was evaluated from UV-Vis ... more The state of the tautomeric equilibria of eleven arylazo pyridone dyes was evaluated from UV-Vis absorption spectra with the aid of the quantum mechanical modeling. NMR analysis and theoretical calculations, by using PCM/xB97X-D/6-311G(d,p) method, confirmed that prepared compounds exist mainly in Hydrazo form. Internal hydrogen bonding in Hydrazo tautomer, analyzed by AIM topological analysis and total electron density at the bond critical point (BCP), confirmed a presence of strong hydrogen bond which contributes to higher stability of Hydrazo form. Linear solvation energy relationships (LSERs) rationalized solvent influence on solvatochromism of all compounds in Hydrazo form and K T by using Kamlet-Taft model. Linear free energy relationships (LFERs) were applied to the substituent-induced NMR chemical shifts (SCS) using SSP (single substituent parameter) and DSP (dual substituent parameter) model. Density plots over the highest occupied (HOMO) and lowest unoccupied molecular orbitals (LUMO) energy surface provide information on the charge transfer during excitation. The molecular electrostatic potential (MEP)
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
h i g h l i g h t s The tautomeric equilibria of title molecules are investigated experimentally ... more h i g h l i g h t s The tautomeric equilibria of title molecules are investigated experimentally and theoretically. Influence of solvent and substituent on UV-vis absorption spectra was examined. K T values of the investigated compounds were determined. ICT process was deduced from Bader's analysis.
Structural Chemistry, 2014
ABSTRACT The tautomeric equilibria between 2-pyridone and 2-hydroxypyridine forms of methoxy, chl... more ABSTRACT The tautomeric equilibria between 2-pyridone and 2-hydroxypyridine forms of methoxy, chloro, and nitro derivatives of 3-cyano-4-(2-, 3-, and 4-substituted phenyl)-6-phenyl-2(1H)-pyridones were evaluated from UV/Vis spectral data. Linear solvation energy relationships of Kamlet–Taft and Catalán-rationalized solvent have influence on tautomeric equilibria. Transmission of substituent effect was analyzed by the Hammett equation. Quantum chemical calculations were performed by density functional theory (B3LYP). The experimental data were interpreted with the aid of time-dependent density functional method. Electron density distribution was analyzed by Bader’s analysis. It was found that substituents of different electronic properties change the extent of conjugation, and affect intramolecular charge transfer character. Theoretical calculations and experimental results gave insight into the influence of the molecular conformation on the transmission of substituent effects, as well as on contribution of different solvent–solute interactions.
HETEROCYCLES, 2008
ABSTRACT
Journal of the Serbian Chemical Society
The substituent and solvent effects on solvatochromism in 3-[(4-substituted)phenylamino]isobenzof... more The substituent and solvent effects on solvatochromism in 3-[(4-substituted)phenylamino]isobenzofuran-1(3H)-ones were studied using experimental and theoretical methodologies. The effect of specific and non-specific solvent-solute interactions on the shifts of UV-Vis absorption maxima were evaluated using the Kamlet-Taft and Catalán solvent parameter sets. The experimental results were studied by density functional theory (DT) and time-dependent density functional theory (TD-DFT). The HOMO/LUMO energies (E HOMO /E LUMO) and energy gap (E gap) values, as well as the mechanism of electronic excitations and the changes in the electron density distribution in both ground and excited states of the investigated molecules were studied by calculation in the gas phase. The electronic excitations were calculated by the TD-DFT method in the solvent methanol. It was found that both substituents and solvents influence the degree of π-electron conjugation of the synthesized molecules and affect the intramolecular charge transfer character.