A. Sadeek

Metal adsorption by agricultural biosorbents: Adsorption isotherm, kinetic and biosorbents chemical structures

Biosorption of Cu(II), Co(II) and Fe(III) ions from aqueous solutions by rice husk, palm leaf and water hyacinth was investigated as a function of initial pH, initial heavy metal ions concentration and treatment time. The adsorption process was examined by two adsorption isotherms: Langmuir and Freundlich isotherms. The experimental data of biosorption process were analyzed using pseudo-first order, pseudo-second order kinetic models. The equilibrium biosorption isotherms showed that the three studied biosorbents possess high affinity and sorption capacity for Cu(II), Co(II) and Fe(III) ions. Rice husk showed more efficiency than palm leaf and water hyacinth. Adsorption of Cu(II) and Co(II) was more efficient in alkaline medium (pH 9) than neutral medium due to the high solubility of metal ion complexes. The metal removal efficiency of each biosorbent was correlated to its chemical structure. DTA studies showed formation of metal complex between the biosorbents and the metal ions. The obtained results showed that the tested biosorbents are efficient and alternate low-cost biosorbent for removal of heavy metal ions from aqueous media.

Metal complexes of the third generation quinolone antibacterial drug sparfloxacin: preparation, structure, and microbial evaluation

The interactions of yttrium chloride, zirconium chloride, and uranium nitrate with sparfloxacin (SPAR) in ethanol, methanol, and acetone were studied. The isolated solid complexes were characterized by elemental analysis, infrared, 1H-NMR and electronic spectra, and thermogravimetric analysis. The results support the formation of [Y(SPAR)2Cl2]Cl ⋅ 12H2O, [ZrO(SPAR)2Cl]Cl ⋅ 15H2O, and [UO2(SPAR)3](NO3)2 ⋅ 5H2O. Infrared spectra of the isolated solid complexes indicate that SPAR is bidentate through the ring carbonyl oxygen and one oxygen of carboxylate. The calculated bond length and force constant, F(U=O), in the uranyl complex are 1.747 Å and 655.29 Nm−1, respectively. The antimicrobial activities of the ligand and metal complexes have been tested against bacteria Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and fungi Penicillium rotatum (P. rotatum) and Trichoderma sp., showing that the complexes exhibit higher antibacterial activity than SPAR.

Complexation and thermogravimetric investigation on tin(II) and tin(IV) with norfloxacin as antibacterial agent

The interaction of tin(II) and tin(IV) chlorides with norfloxacin (NOR) has been investigated. Elemental analysis, infrared, mass spectra and thermal analysis have been used to characterize the isolated solid complexes. The results support the formation of complexes with the formula [Sn(NOR)2]Cl2·4H2O and [Sn(NOR)3]Cl4. The infrared spectra of the isolated solid complexes suggested that NOR act as bidentate ligand through the carbonyl oxygen atom and one oxygen atom of the carboxylic group forming six-membered rings with the tin ions. The interpretation, mathematical analysis and evaluation of kinetic parameters of thermogravimetric (TGA) and its differential (DTG), such as entropy of activation, pre-exponential factors, activation energy evaluated by using Coats–Redfern and Horowitz–Metzger equations are carried out for two complexes. The data obtained indicate that the two complexes decompose in one stage and general mechanisms describing the decomposition are suggested. Furthermore, the electronic, and 1H NMR spectra have been studied.

Spectroscopic, structure and antimicrobial activity of new Y(III) and Zr(IV) ciprofloxacin.

The preparation and characterization of the new solid complexes [Y(CIP)2(H2O)2]Cl(3)·10H2O and [ZrO(CIP)2Cl]Cl·15H2O formed in the reaction of ciprofloxacin (CIP) with YCl3 and ZrOCl(2)·8H2O in ethanol and methanol, respectively, at room temperature were reported. The isolated complexes have been characterized with elemental analysis, IR spectroscopy, conductance measurements, UV-vis and 1H NMR spectroscopic methods and thermal analyses. The results support the formation of the complexes and indicate that ciprofloxacin reacts as a bidentate ligand bound to the metal ion through the pyridone oxygen and one carboxylato oxygen. The activation energies, E*; entropies, ΔS*; enthalpies, ΔH*; Gibbs free energies, ΔG*, of the thermal decomposition reactions have been derived from thermogravimetric (TGA) and differential thermogravimetric (DTG) curves, using Coats-Redfern and Horowitz-Metzeger methods. The proposed structure of the two complexes was detected by using the density functional theory (DFT) at the B3LYP/CEP-31G level of theory. The ligand as well as their metal complexes was also evaluated for their antibacterial activity against several bacterial species, such as Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and antifungal screening was studied against two species (Penicillium (P. rotatum) and Trichoderma (T. sp.)). This study showed that the metal complexes are more antibacterial as compared to free ligand and no antifungal activity observed for ligand and their complexes.

Preparation, thermal and vibrational studies of [UO2(acac-o-phdn)(L)] (L=H2O, py, DMF and Et3N)

Four new dioxouranium(VI) complexes, [UO2(acac-o-phdn)(L)] where L = H2O, py, DMF and Et3N, with the tetradentate dibasic Schiff base (acac-o-phdn), derived from condensation of acetylacetone with o-phenylene diamine have been synthesized. The infrared spectra were obtained and full assignments of all the observed vibrations are proposed on the basis of C2v symmetry for H2O and py complexes and Cs for the other two complexes, respectively. The bond stretching force constant and bond length of the U=O bond for the four complexes were calculated. Differential thermal analysis (DTA) and thermogravimetric (TG) analysis of the complexes were also carried out.

Synthesis, characterization and antimicrobial investigation of some moxifloxacin metal complexes

The new complexes of moxifloxacin (MOX), with Ti(IV), Y(III), Pd(II) and Ce(IV) have been synthesized. These complexes were then characterized by melting point, magnetic studies and spectroscopic techniques involving infrared spectra (IR), UV-Vis, (1)H NMR. C, H, N and halogen elemental analysis and thermal behavior of complexes also investigated. The results suggested that the molar ratio for all complexes is M: MOX=1:2 where moxifloxacin acts as a bidentate via one of the oxygen atoms of the carboxylate group and through the ring carbonyl group and the complexes have the following formula [Ti(MOX)(2)](SO(4))(2)·7H(2)O, [Y(MOX)(2)Cl(2)]Cl·12H(2)O, [Pd(MOX)(2)(H(2)O)(2)]Cl(2)·6H(2)O and [Ce(MOX)(2)](SO(4))(2)·2H(2)O. The activation energies, E*, enthalpies, ΔH*, entropies, ΔS* and Gibbs free energies, ΔG*, of the thermal decomposition reactions have been derived from thermogravimetric (TGA) and differential thermogravimetric (DrTG) curves, using Coats-Redfern (CR) and Horowitz-Metzger (HM) methods. The antimicrobial activity of these complexes has been evaluated against three Gram-positive and three Gram-negative bacteria and compared with the reference drug moxifloxacin. The antibacterial activity of Ti(IV) complex is significant for E. coli K32 and highly significant for S. aureus K1, B. subtilis K22, Br. otitidis K76, P. aeruginosa SW1 and K. oxytoca K42 compared with free moxifloxacin.

Synthesis, infrared spectra and thermal investigation of gold(III) and zinc(II) urea complexes. A new procedure for the synthesis of basic zinc carbonate

Reaction of urea with sodium tetrachloroaurate(III) dihydrate and zinc(II) chloride has been investigated at room and elevated temperature (∼90°C) producing three new compounds: [Au(urea)4]Cl3·2H2O, [Au2(NH2)2Cl2(NCO)(OH)]·H2O and 2ZnCO3·3Zn(OH)2. The infrared spectra were recorded and the observed bands were assigned. The binuclear gold complex and basic zinc carbonate basic were also investigated by thermal analysis, and general mechanisms describing their decompositions are suggested.

Spectroscopic studies on the reaction of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane

Abstract The interaction of iodine with the nitrogen cyclic base 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMTACTD) is studied spectrophotometrically in CHCl 3 and the resonance Raman spectrum of the solid product is recorded. The results indicate the formation of the polyiodide species with the formula [(TMTACTD)I] + . I 9 − . The resonance Raman spectrum of the product suggests that the enneaiodide, I 9 − , does indeed contain the I 5 unit and this implies that I 9 − exists as (I 5 − ) (2I 2 ) where the I 5 − portion has a bent configuration with C 2 ν symmetry. All bond vibrations for the I 5 and I 2 units are observed and assigned.

Spectroscopic, thermal analysis, and antimicrobial evaluation of new Y(III), Zr(IV), and U(VI) ibuprofen complexes

New complexes of Y(III), Zr(IV), and U(VI) with the anti-inflammatory drug ibuprofen (IBU) have been synthesized and characterized by elemental analysis, spectroscopic techniques (UV-Visible, IR, and 1H NMR), magnetic moment determination, conductance measurements, and thermal analyses (thermogravimetric and differential thermogravimetric). The anti-inflammatory drug acts as bidentate chelate bound to metal ions through the deprotonated carboxylate. The calculated bond length and force constant, F(U=O), in the uranyl complex are 1.815 Å and 671.69 Nm−1, respectively. The metal–ligand binding of the Zr(IV) and Y(III) complexes is predicted using density functional theory at the B3LYP-CEP-31G level of theory and total energy, dipole moment estimation of different Zr(IV) and Y(III) ibuprofen structures. The antibacterial activity of the ligand, metal salts, and metal complexes have been tested, showing that the complexes are significant against all six bacterial species compared with IBU and metal salts.

Preparation and infrared spectrum of the bridged diacetato complex [Cu2(O)(H2O)2(OOCCH3)2 formed by the reaction of urea with copper (II) acetate

Abstract The bridged diacetato complex [Cu2(O)(H2O)2(OOCCH3)2] has been obtained by reacting aqueous solutions of Cu(OOCCH3)2 · H2O and urea at about 70°C. The reaction product was characterized through elemental analysis and i.r. measurements. The i.r. spectrum shows the characteristic bands of coordinated acetate ions and water, and was interpreted on the basis of C2v symmetry for the complex. A general mechanism describing the formation of [Cu2(O)(H2O)2(OOCCH3)2] is proposed.