فتحي الهادي عمر الصالح
رئيس قسم الدراسة والامتحانات بمدرسة العلوم الاساسية
عضو هيئة تدريس قار
المؤهل العلمي: دكتوراه
الدرجة العلمية: أستاذ مشارك
التخصص: كيمياء عضوية - كيمياء
قسم علوم الكيمياء - مدرسة العلوم الأساسية
Kinetics of the reaction of 5-substituted orotic acids with diazodiphenylmethanJournal Article
Rate konstants for the reaction of eight 5-substituted orotic acids with diazodiphenylmethane (DDM) in dimethylformamide (DMF) were determined at 30 ºC by the known spectrophotometricmethod. The determined rate constants were correlated with the equations: logk2 = ασ1+βσR+h logk2 = ασ1+βσR+ψν+h to detect the presence and investigate the influence of both electrical and steric substituent effects. The obtained results show that the electrical effect (the localized – field and delocalized – resonance) is predominant and that the steric effect, althought present, is releatively small in this reaction.
Batislav Ž. Jovanović, Fathi H. Assaleh, Aleksandar D. Marinković, (08-2004), Journal of Serbian Chemical Society: Serbian Chemical Society, 69 (11), 949-953
Effect of substituents on the 13C chemical shifts of the azomethine carbon atom of N-(substituted phenylmethylene)-3- and -4-aminobenzoic acidsJournal Article
13C chemical shifts of the azomethine carbon atom for N-(substituted phenylmethylene)-3- and -4-aminobenzoic acids having a wide range of substituent effects, were determined in deuterated DMSO solution. Good Hammett correlations of the 13C NMR chemical shifts of azomethine carbons with electrophilic substituent constants for electron-donor substituents for both series of acids indicate an important resonance interaction of the substituents on the benzylidene ring with the azomethine carbon atom. On the other hand, good correlations of the 13C NMR chemical shifts of azomethine carbon atom of both series of acids with inductive substituent constants for electron-acceptor substituents in benzylidene ring indicates that the chemical shifts are influenced only by inductive effect of the substituents. The demand for electrons by the azomethine carbon atom in both investigated series have been compared, discussing the mode of transmission of substituent effects, both inductive and resonance, in relation to the geometry of investigated imines.
B. Ž. Jovanović, A. D. Marinković, F. H. Assaleh, (06-2006), Journal of Molecular Structure: Elsevier, 744 (747), 411-316
Investigation of the reactivity of 4-pyrimidinecarboxylic, 6-hydroxy-4-pyrimidinecarboxylic and 5-hydroxyorotic acids with diazodiphenylmethane in various alcoholsJournal Article
Rate constants for the reaction of diazodiphenylmethane (DDM) with 4-pyrimidinecarboxylic, 6-hydroxy-4-pyrimidinecarboxylic and 5-hydroxyorotic acids were determined in twelve protic solvents at 30 °C using the well known UV-spectrophotometric method. The second order rate contants for the examined acids were correlated using the appropriate solvent parameters by the equation log k = log k0 + af(e) + bs * + cngH were f(e) is the Kirkwood function of relative permittivity [(e-l)/(2e + 1 )], s * is the Taft polar constant for the alkyl group R in the alcohol ROH, and nyH is themumber of hydrogen atoms in the (-position in the alcohol. The results obtained for the investigated acids were compared with the corresponding results for benzoic, 2- and 3-hydroxybenzoic acids and the influence of the structure of the investigated acids on the reactivity in hydroxylic solvents is discussed. It was also possible to evaluate and distinguish the specific and non-specific solvent effects and their influence on the reaction rate.
Fathi H. Assaleh, Aleksandar D. Marinković, Saša Ž. Drmanić, Bratislav Ž. Jovanović, (08-2007), Journal of Serbian Chemical Society: Serbian Chemical Society, 73 (3), 205-214
Carbon-13 substituent chemical shifts in N-1-p-substituted phenyl-5-methyl-4-carboxy uracilsJournal Article
The 13C NMR chemical shifts of seven N-1-p-substituted phenyl-5-methyl-4-carboxy uracils have been measured in deuterated dimethyl sulfoxide (DMSO-d6). The correlation analysis for the substituent-induced chemical shifts (SCS) with inductive (σI), and various resonance (σR) parameters were carried out through SSP (single substituent parameter), DSP (dual substituent parameter), and DSP-NLR (dual substituent parameter non-linear resonance) methods, as well as through multiple regression analysis. The presented calculation relative to the polar and resonance effects accounts satisfactorily for substituent effects at uracil carbon atoms. Negative ρ values were found for several correlations (reverse substituent effect).
Fathi H. Assaleh, Aleksandar D. Marinković, Bratislav Ž. Jovanović, Janos Csanádi, (05-2007), Journal of Molecular Structure: Elsevier, 833 (1), 53-57
Detailed solvent, structural, quantum chemical study and antimicrobial activity of isatin Schiff baseJournal Article
The ratios of E/Z isomers of sixteen synthesized 1,3-dihydro-3-(substituted phenylimino)-2H-indol-2-one were studied using experimental and theoretical methodology. Linear solvation energy relationships (LSER) rationalized solvent influence of the solvent–solute interactions on the UV–Vis absorption maximashifts (νmax) of both geometrical isomers using the Kamlet-Taft equation. Linear free energy relationships (LFER) in the form of single substituent parameter equation (SSP) was used to analyze substituent effect on pKa, NMR chemical shifts and νmax values. Electron charge density was obtained by the use of Quantum Theory of Atoms in Molecules, i.e. Bader's analysis. The substituent and solvent effect on intramolecular charge transfer (ICT) were interpreted with the aid of time-dependent density functional (TD-DFT) method. Additionally, the results of TD-DFT calculations quantified the efficiency of ICT from the calculated charge-transfer distance (DCT) and amount of transferred charge (QCT). The antimicrobial activity was evaluated using broth microdilution method. 3D QSAR modeling was used to demonstrate the influence of substituents effect as well as molecule geometry on antimicrobial activity
Dominik R. Brkić, Aleksandra R. Božić, Aleksandar D. Marinković, Miloš K. Milčić, Nevena Ž. Prlainović, Fathi .H .O Assaleh, Ilija N. Cvijetić, Jasmina B. Nikolić, Saša Ž.Drmanić, (05-2018), Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy: Elsevier, 196 (5), 16-30
Multivariate assessment of azo dyes' biological activity parametersJournal Article
Lipophilicity as key molecular descriptor of potential biological activity for selected derivatives of azo dyes was determined mathematically, by using relevant software packages and by reversed-phase thin-layer chromatography (RPTLC) on C18 and cyano modified carriers in mixtures of water/n-propanol and water/acetone. The obtained chromatographic parameters, RM0 and m, of the examined azo dyes were correlated with the standard measure of lipophilicity, log P, important pharmacokinetic predictors and selected toxicity parameters applying linear regression analysis. Thereby, good correlations for each applied system were obtained (average correlation coefficient, r, 0.944, 0.885 and 0.919). Also, the correlations between the studied parameters of azo dyes were examined applying two multivariate methods (Cluster Analysis and Principal Component Analysis). It was shown that the polarity of the substituent, and to a lesser extent its electronic effects has the greatest influence on the studied parameters of the azo dyes derivatives. Multivariate methods pointed out the similarity of the chromatographic retention constant, RM0, with the parameters of lipophilicity, unlike the chromatographic parameter m, which exhibits better agreement with the toxicity parameters.
Gyöngyi Vastag, Suzana Apostolov, Borko Matijević, Fathi Assaleh, (05-2018), Journal of Chromatography B: Elsevier, 1084 (1084), 141-149
Solvatochromism and azo–hydrazo tautomerism of novel arylazo pyridone dyes: Experimental and quantum chemical studyJournal Article
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/ωB97X-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 Hydrazoform and KT 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) surface map was plotted over the optimized geometry of the molecules in order to visualize electron density distribution and explain origin of solvent/solute interactions.
Ismail Ajaj, Fathi Assaleh, Jasmina Markovski, Milica Rančić, Danijela Brkoviće, Miloš Milčić, Aleksandar D. Marinković, (12-2019), Arabian Journal of Chemistry: Elsevier, 12 (8), 3463-3478
QSRR approach in examining selected azo dyesJournal Article
Azo dyes as the most numerous and widely applied class of synthetic dyes in various industries at the same Azo dyes as the most numerous and widely applied class of synthetic dyes in various industries at the same time represent the great polluter of the aquatic systems and environment. Most of them are hydrophobic and resistant to degradation, but also they express diverse biological activity. The preliminary examinations of the bioactivity of the compounds include the estimation of their lipophilicity. The lipophilicity, as the key molecular descriptor for assuming an activity in a biological system for group of thiouracil azo dyes, was determined by the reversed-phase thin-layer chromatography (RPTLC18F254s) in different mixtures of water and (ethanol, i-propanol, dioxane, tetrahydrofurane) and mathematically using relevant software packages. The insight into the relationship between the chromatographic retention parameters, R0m and m of azo dyes with the partition coefficient log P, was attained by applying the linear regression analysis, Cluster analysis, and principal component analysis. All the applied methods have resulted in good agreements of the studied lipophilicity parameters of azo dyes. Also, these methods provided significant informations about the influence of the organic modifier on one side as well as the impact of the polarity and the electronic effect of substituent of examined dyes on their lipophilicity.
Gyöngyi Vastag, Suzana Apostolov, Borko Matijević, Fathi Assaleh, (10-2016), Journal of Liquid Chromatography & Related Technologies: Taylor & Francis Group, 39 (14), 674-681
Conformational stability of 5-substituted orotic acid derivatives analysed by measuring 13C NMR chemical shifts and applying linear free energy relationshipsJournal Article
Conformational stability of various 5-substituted orotic acid derivatives was studied by applying linear free energy relationships (LFER) to the 13C NMR chemical shifts. The correlation analysis for the substituent-induced chemical shifts (SCS) with inductive (σI), and various resonance (σR) parameters were carried out through Single Substituent Parameter (SSP) and Dual Substituent Parameter (DSP) methods, and multiple regression analysis. Good Hammett correlations for all carbons were obtained, while electrophilic substituent constants better fitted for C2 carbon with electron-donor substituents. Conformational analysis of various derivatives using RB3LYP/6-311++G (3df,3dp) DFT method, together with 13C NMR data suggests that most of the substituted orotic acid derivatives exist in planar conformation, except nitro and alkyl substituted derivatives. Internal rotation of carboxylic group showed significant impact on the extent of conjugative interaction making syn conformation more stable in all the derivatives studied. Further, of all 5-substituted orotic acid derivatives, diketo form proved to be the most stable form compared to zwitterionic and enol tautomeric forms. Optimized geometries and transmission effects of particular substituent through well-defined π-resonance units suggest that these units behave as isolated as well as conjugated fragments, depending on the type of substituent
Fathi Assaleh, Aleksandar D. Marinković, Jasmina Nikolić, Nevena Ž.Prlainović, Saša Drmanić, Mohammad M.Khan, Bratislav Ž. Jovanović, (12-2019), Arabian Journal of Chemistry: Elsevier, 12 (8), 3357-3366