Khater, M. M., H. B. Hassib, Y. M. Issa, and S. H. Mohammed, "Surface morphology changes of polymer membrane and carbon paste sertraline sensors", Talanta, vol. 134, pp. 546 - 553, 2015. AbstractWebsite

Abstract Polymer membrane and chemically modified carbon paste (CMCP) sensors for determination of sertraline \{HCl\} (Ser-Cl) incorporating sertraline tetraphenylborate (Ser-TPB) as an electro-active material were constructed. They showed a rapid and linear response for Ser-ion over the concentration range 0.01–10.00 mmol L−1. The limits of detection were 2.80 and 9.55 μmol L−1, and Nernastian slopes were 56.60, 59.60 mV decade−1 for membrane and \{CMCP\} sensors for batch method. In flow injection analysis (FIA), the electrodes revealed comparatively good selectivity for Ser-ion with regard to a wide variety of different cations, sugars, and amino acids. The addition of different anionic additives, namely sodium tetraphenylborate (NaTPB), potassium tetraphenylborate (KTPB), potassium tetrakis[3,5-bis-(triflouromethyl)phenyl]borate (KTFMPB), and sodium tetrakis[3,5-bis(trifluoro-methyl)phenyl]borate (NaTFMPB), to the prepared mixture improved their response characteristics. The surface morphologies of membrane films containing \{PVC\} only (blank), plasticizer+PVC, Ser-TPB+plasticizer+PVC, and Ser-TPB +plasticizer+PVC+additive were studied using scanning and atomic force electron microscopes. These sensors had been used in the potentiometric titration of Ser-ion against NaTPB. Standard addition method for the pure raw material and some of its pharmaceutical tablets was used for Ser-Cl determination. The obtained results were tested for their repeatability and reproducibility and were statistically treated by F- and t- tests.

Khater, M. M., Y. M. Issa, H. B. Hassib, and S. H. Mohammed, "Dynamic potential and surface morphology study of sertraline membrane sensors", Journal of Advanced Research, vol. 6, no. 3, pp. 459 - 469, 2015. AbstractWebsite

Abstract New rapid, sensitive and simple electrometric method was developed to determine sertraline hydrochloride (Ser-Cl) in its pure raw material and pharmaceutical formulations. Membrane sensors based on heteropolyacids as ion associating material were prepared. Silicomolybdic acid (SMA), silicotungstic acid (STA) and phosphomolybdic acid (PMA) were used. The slope and limit of detection are 50.00, 60.00 and 53.24 mV/decade and 2.51, 5.62 and 4.85 μmol L−1 for Ser-ST, Ser-PM and Ser-SM membrane sensors, respectively. Linear range is 0.01–10.00 for the three sensors. These new sensors were used for the potentiometric titration of Ser-Cl using sodium tetraphenylborate as titrant. The surface morphologies of the prepared membranes with and without the modifier (ion-associate) were studied using scanning and atomic force microscopes.

Issa, Y. M., E. A. L. Ansary, O. E. Sherif, and H. B. Hassib, "Charge–transfer complexes of pyrimidine Schiff bases with aromatic nitro compounds", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 79, no. 3, pp. 513 - 521, 2011. AbstractWebsite

Charge–transfer (CT) complexes of pyrimidine Schiff bases, derived from condensation of 2-aminopyrimidine and substituted benzaldehydes, with some aromatic polynitro compounds were prepared and investigated using IR, UV, visible and 1H \{NMR\} spectroscopy. For all solid complexes, the main interaction between the donor and acceptor molecules takes place through the π–π* interaction. Strong and some weak acidic acceptors, in addition interact through proton transfer from the acceptor molecule to the basic centre of the electron donor. Also, an n–π* transition was detected in some complexes.

Ibrahim, M. E., T. A. Lasheen, H. B. Hassib, and A. S. Helal, "Oxidative leaching kinetics of U(IV) deposit under acidic oxidizing conditions", Journal of Environmental Chemical Engineering, vol. 1, no. 4, pp. 1194 - 1198, 2013. AbstractWebsite

Abstract Oxidative leaching kinetics of U(IV) deposit in dilute \{H2SO4\} solution with \{H2O2\} as oxidizing agent has been investigated. The kinetics results showed that, the rate is controlled by diffusion through the “product” layer composed of the associated concomitants. The leaching process follows the kinetic model 1 − 2/3X − (1 − X)2/3 = kt with an apparent activation energy of 22.803 kJ/mol. It was found that both sulfuric acid and hydrogen peroxide have significant effects on the leaching rate of uranium species. The reaction orders of \{H2SO4\} and \{H2O2\} were determined as 1.073 and 2.084, respectively. It is also found that particle size presents a clear effect on uranium leaching rate, and the rate constant (k) is proportional to d−2. The kinetic model for leaching uranium from U(IV) deposit is expressed as 1 − 2 / 3 X − ( 1 − X ) 2 / 3 = 3.34 d 0 − 2 [ H 2 \{SO\} 4 ] 1.073 [ H 2 O 2 ] 2.084 exp ( − 22,803 / R T ) t which coincided with the experimental results.

Issa, Y. M., H. B. Hassib, and H. E. Abdelaal, "1H NMR, 13C \{NMR\} and mass spectral studies of some Schiff bases derived from 3-amino-1,2,4-triazole", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 74, no. 4, pp. 902 - 910, 2009. AbstractWebsite

Heterocyclic Schiff bases derived from 3-amino-1,2,4-triazole and different substituted aromatic aldehydes are prepared and subjected to 1H NMR, 13C \{NMR\} and mass spectral analyses. 1H \{NMR\} spectra in \{DMSO\} exhibit a sharp singlet within the 9.35–8.90 ppm region which corresponds to the azomethine proton. The position of this signal is largely dependent on the nature of the substituents on the benzal moiety. It is observed that the shape, position and the integration value of the signal of the aromatic proton of the triazole ring (5C) are clearly affected by the rate of exchange, relaxation time, concentration of solution as well as the solvent used. 13C \{NMR\} is taken as substantial support for the results reached from 1H \{NMR\} studies. The mass spectral results are taken as a tool to confirm the structure of the investigated compounds. The base peak (100%), mostly the M-1 peak, indicates the facile loss of hydrogen radical. The fragmentation pattern of the unsubstituted Schiff base is taken as the general scheme. Differences in the other schemes result from the effect of the electronegativity of the substituents attached to the aromatic ring.

Darwish, K. A., M. Mounir, A. L. El-Ansary, and H. B. Hassib, "Electrical properties of charge transfer complexes of 2-aminopyrimidine and 2-aminopyrazine schiff bases with nitrobenzene derivatives", Thermochimica Acta, vol. 114, no. 2, pp. 265 - 271, 1987. AbstractWebsite

A study of the electrical properties of charge-transfer (CT) complexes of 2-aminopyrimidine and 2-aminopyrazine Schiff bases with mtrobenzene derivatives has been done. The investigation comprises the 1:1 as well as the 1:2 donor: acceptor (D:A) complexes. The behaviour of the electrical conductivity for all \{CT\} complexes m the studied range of temperatures indicates a semiconducting character. The 1:1 \{CT\} complexes show higher electrical conductivity values with respect to those of the corresponding Schiff bases due to the increased π-electron delocalization in the \{CT\} complexes. The decrease of activation energy in dinitrobenzene \{CT\} complexes with respect to the corresponding Schiff base is lower than that observed in trinitrobenzene derivatives. This confirms that the molecular complexes of the former are much weaker than the latter. The 1:2 complexes are characterized by higher activation energy values (lower electrical conductivity) with respect to the corresponding 1:1 complexes: a behaviour which is due to participation of both rings in \{CT\} leading to an increased localization of the π-electrons. There is a correlation between the dielectric constant for most of the studied \{CT\} complexes and their electrical conductivities.

Mounir, M., K. A. Darwish, A. L. El-Ansary, and H. B. Hassib, "The electrical properties of some 2-aminopyrimidine and 2-aminopyrazine schiff bases", Thermochimica Acta, vol. 114, no. 2, pp. 257 - 263, 1987. AbstractWebsite

The electrical properties of some Schiff bases of 2-aminopyrimidine and 2-aminopyrazine with benzaldehyde derivatives have been investigated. Such measurements have rarely been done on these compounds. The positive temperature coefficient of electrical conductivity (dσ/dT) found for all the samples investigated is evidence for the semiconducting character within the range of temperature studied. For the compounds studied, a correlation between the electrical properties and their chemical structure is established. The mechanism of the conduction process in these samples is also studied.

Abdel-Latif, S. A., H. B. Hassib, and Y. M. Issa, "Studies on some salicylaldehyde Schiff base derivatives and their complexes with Cr(III), Mn(II), Fe(III), Ni(II) and Cu(II)", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 67, no. 3–4, pp. 950 - 957, 2007. AbstractWebsite

The formation constants of some transition metal ions Cr(III), Mn(II), Fe(III), Ni(II) and Cu(II) binary complexes containing Schiff bases resulting from condensation of salicylaldehyde with aniline (I), 2-aminopyridine (II), 4-aminopyridine (III) and 2-aminopyrimidine (IV) were determined pH-metrically in ethanolic medium (80%, v/v). The formation constants were determined for all binary complexes. The important infrared (IR) spectral bands corresponding to the active groups in the four ligands and the solid complexes under investigation were studied. The solid complexes have been synthesized and studied by thermogravimetric analysis. The thermal dehydration and decomposition of these complexes were studied kinetically using the integral method applying the Coats–Redfern equation. It was found that the thermal decomposition of the complexes follow second order kinetics. The thermodynamic parameters of the decomposition are also reported. The electronic absorption spectra of the investigated ligands were carried out to determine the pKa values spectrophotometrically.

Lasheen, T. A., M. E. Ibrahim, H. B. Hassib, and A. S. Helal, "Recovery of molybdenum from uranium bearing solution by solvent extraction with 5-Nonylsalicylaldoxime", Hydrometallurgy, vol. 146, pp. 175 - 182, 2014. AbstractWebsite

Abstract 5-Nonylsalicylaldoxime, \{LIX\} 622N was used to extract and recover Mo(VI) from sulfate leach liquor containing Mo(VI) and U(VI). The extraction parameters were optimized as 10%(v/v) \{LIX\} 622N diluted in kerosene at equilibrium pH 1.0 and O/A phase ratio = 1:1. Under these conditions, complete extraction of Mo(VI) was realized by a two-stage counter current extraction. The formed complex MoO2R2 is assessed by \{FTIR\} analysis. The molybdenum content in the organic phase was stripped using a mixture of 2 M \{NH4OH\} + 2 M (NH4)2CO3. It was precipitated at pH value 2.0 as ammonium molybdate. After drying, thermal decomposition high purity (> 99.9%) of MoO3 was produced. The effect of temperature on the Mo(VI) extraction process showed that, the extraction process is exothermic with enthalpy change − 24.514 kJ mol− 1.

Hassib, H. B., and S. A. Abdel-Latif, "Potentiometric, spectrometric, thermal and conductimetric studies on some 3-phenyl-4-(arylazo)-5-pyrazolones and their complexes with divalent cobalt metal ion", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 59, no. 11, pp. 2425 - 2434, 2003. AbstractWebsite

3-phenyl-4-arylazo-5-pyrazolones (I–IV) have been synthesized and characterized by elemental, infrared (IR), ultraviolet and visible spectra (UV–Vis), proton nuclear magnetic resonance (1H NMR) and Mass spectra. It has been proved that these compounds exhibit a keto-enol tautomerism in solution. The donor character of the substituent increases the enol form. The ionization constants of the investigated ligands have been determined potentiometrically and found to decrease in the order OCH3(IV)>CH3(III)>H(I)>Cl(II). The Co(II) complexes of the investigated 3-phenyl-4-arylazo-5-pyrazolones (I–IV) have been prepared and characterized by elemental and thermal analyses as well as by IR, UV–Vis, electronic transition, potentiometric, conductimetric and magnetic measurements. The data suggest octahedral geometry for Co(II) (1:1) complexes and tetrahedral for Co(II) (2:3) complexes.