A. O. Youssef

Molybdenum and tungsten complexes of biquinoline. Crystal structure of W(CO)4(2,2′-biquinoline)

M(CO)6 (M = Mo and W) reacts with 2,2′-biquinoline (biq) to yield tetracarbonyl derivatives M(CO)4(biq). Crystals suitable for X-ray structure determination of W(CO)4(biq) were isolated from benzene solution. The u.v.–vis. spectra of the complexes exhibited visible transitions due to metal-to-ligand charge-transfers. Electrochemical investigation of the complexes showed some irreversible, reversible and quasi-reversible redox reactions due to tautomeric interconversions through electron transfer. The thermal properties of the complexes were also investigated using the thermogravimetric technique.

Potentiality of uranium adsorption from wet phosphoric acid using amine-impregnated cellulose

Abstract The prepared amine-impregnated cellulose (AIC) was found to be an efficient adsorbent for uranium originated from El-Sebaiya phosphate ore. The impregenation process was carried out by copolymerization between pretreated cellulose and a mixture of (tri-ethyl amine and epi-chorohydrine). In the present work, two working solutions were used. The first solution was a synthesized phosphoric acid (35% P2O5 and 100 ppm U) used for optimizing the loading process of uranium. The second one was used as a case study for adsorption of uranium from a real phosphoric acid (WPPA) prepared from El-Sebaiya phosphate ore (P2O5 35%, 100 ppm U). The obtained equilibrium data were found to be satisfactory fitted with Langmuir isotherm. A maximum-metal uptake of 56.5 mgU/g AIC was observed at the obtained optimum conditions. Also, elution process of uranium has been achieved at 1 M of 30 ml Na2CO3 solution/g AIC after 15 min contact time. From the latter, a marketable product of sodium di-uranate was prepared.

Enhancement of the efficiency of a salivary alpha amylase biomarker for the sympathetic nervous system by a nano-optical sensor Tb–acetyl acetone complex

A new nano-optical sensor Tb–acetylacetone (Tb–ACAC) complex is developed for assessing the activity of a salivary alpha amylase enzyme. The salivary alpha amylase enzyme is used as a biomarker for the assessment of the sympathetic nervous system activity in different saliva samples of unstressed, physically active (flight and fight), or psychologically active (examination) and smoking or non-smoking humans aged 20–55 years. The assessment of the alpha amylase activity is carried out through quenching of the luminescence intensity of the nano optical sensor Tb–ACAC complex at 545 nm by 2-chloro-4-nitrophenol (2-CNP) produced from the reaction of the enzyme with 2-chloro-4-nitrophenyl-α-D-maltotrioside (CNPG3) as a substrate. The remarkable quenching of the luminescence intensity at 545 nm of nano Tb–ACAC doped in a sol–gel matrix with various concentrations of 2-CNP was successfully used as an optical sensor for the assessment of α-amylase activity. A calibration plot was achieved over a concentration range of 3.0 × 10−4–8.0 × 10−9 mol L−1 2-CNP and over a linear range of enzyme activity of 0.5–300 U L−1 with a correlation coefficient of 0.997 and a detection limit of 1.2 × 10−9 mol L−1 and 0.05 U L−1, respectively. The method was used satisfactorily for the assessment of α-amylase activity as a biomarker for the sympathetic nervous system in all studied cases of human saliva.

Enrofloxacin Assessment by the Enhancement of the Red Emission of Eu3+ Optical Sensor

Abstract The efficiency of excited-state interaction between Eu3+ and the industrial product Enrofloxacin (EFX) has been studied in different solvent. High luminescence intensity peak at 617 nm of europium complex in acetonitrile was obtained. The photophysical properties of the red emissive Eu3+ complex have been elucidated, the europium was used as optical sensor for the assessment of Enrofloxacin in the pharmaceutical tablets and serum sample at pH 7.8 and λex=395 nm with a concentration range 1.0 ×10-7-1.0×10-5 mol L-1 of Enrofloxacin, correlation coefficient of 0.998 and detection limit of 7.5 ×10-8 mol L-1.