Gaber M. Abu El-Reash

Ligational behaviour of biacetylmonoxime nicotinoyl hydrazone (H2BMNH) towards transition metal ions

SummaryThe synthesis and characterization of MnII, CoII, NiII, CuII, ZnII, CdII UO22+, CrIII and FeIII complexes of biacetylmonoxime nicotinoyl hydrazone (H2BMNH) are reported. Elemental analysis, molar conductance, magnetic moment and spectral (i.r., visible and n.m.r.) measurements have been used to characterize the complexes. I.r. spectral data show that the ligand behaves in a bidentate and/or tridentate manner. An octahedral structure is proposed for the MnII, NiII, CrIII and FeIII complexes, while a square-planar structure is proposed for both CoII and CuII complexes on the basis of magnetic and spectral measurements.

Synthesis, Spectroscopic, and Magnetic Properties of Some Transition Metal Complexes with 4‐(2‐Pyridyl)‐1‐(diacetylmonoxime)‐3‐thiosemicarbazide

Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and dioxouranium(VI), (UO2 2 +), complexes of 4‐(2‐pyridyl)‐1‐diacetylmonoxime‐3‐thiosemicarbazone (H2DMPT) have been synthesized and characterized by elemental analyses, molar conductance, spectral (IR, visible and NMR) and magnetic moment measurements. IR spectral data show that the ligand behaves in a bi, tri, and/or tetradentate manner. An octahedral structure is proposed for [Cr(HDMPT)Cl2(H2O)], [Mn(H2DMPT)Cl2(H2O)], [Ni(H2DMPT)Cl2(H2O)] and [Ni(HDMPT)(OAc)(H2O)2] while a square‐planar structure is suggested for [Pd(HDMPT)2], [Cu2(DMPT)Cl2(H2O)]·H2O and [Co(DMPT)2].

Synthesis, Spectral and Magnetic Investigation of 4(2-Pyridyl)-Isatin-3-Thiosemlcarbazone Complexes

Abstract Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO2 2+complexes of isatin 4(2-pyridyl)-3-hiosemicarbazone, H2IPT, have been synthesed and characterized by elemental analyses, molar conductance, spectral (i.r., visible and n. m. r.) and magnetic moment measurements. I. r. spectra show that H2IPT behaves as a bidentate (ON or SN) end a tridentate ONS in a neutral or anionic form. An octahedral structure is proposed Co(HIPT)Cl.3H2O, Co(HIPT)2. 2H2 O, Si(HIPT)Ac.2H2 0 and Cu(H2IPT)2 (Ac)2 complexes and square-planar structure for the Cu(HIPT)Cl.2H2O complex on the basis of spectra and magnetic studies. The molar conductivities for all complexes were in the range of non-electrolytes.

TRANSITION METAL COMPLEXES DERIVED FROM 2-HYDROXYIMINO-3-(2'-HYDRAZONOPYRIDYL)BUTANE

SummaryThe complexes of MnII, CoII, NiII, CuII, ZnII, CdII, HgII, CoIII and UO22+ ions with 2-hydroxyimino-3-(2′-hydrazonopyridyl)-butane (HL) have been synthesised and characterized by elemental analyses, molar conductivities, magnetic measurements and spectral (i.r., visible, n.m.r.) studies. I.r. spectra show that HL behaves as a neutral or mononegative ligand and binds in a bidentate and/or tridentate manner. Also, HL behaves as oxidizing agent towards CoII forming diamagnetic CoIII complexes depending on the preparative conditions. Different stereochemistries are proposed for MnII, CoIII, CoII, NiII and CuII on the basis of spectral and magnetic studies.

Photo-activation of Single Molecule Magnet Behavior in a Manganese-based Complex

A major roadblock to fully realizing molecular electronic devices is the ability to control the properties of each molecule in the device. Herein we report the control of the magnetic properties of single-molecule magnets (SMMs), which can be used in memory devices, by using a photo-isomerizable diarthylenthene ligand. Photo-isomerization of the diarylethene ligand bridging two manganese salen complexes with visible light caused a significant change in the SMM behavior due to opening of the six-membered ring of diarylethene ligand, accompanied by reorganization of the entire molecule. The ring-opening activated the frequency-dependent magnetization of the complex. Our results are a major step towards the realization of molecular memory devices composed of SMMs because the SMM behaviour can be turned on and off simply by irradiating the molecule.

Ligational behaviour of a tetradentate NONS donor ligand towards some transition metal ions

SummaryThe synthesis and characterization of CrII, MnII, FeII, CoII, NiII, PdII, CuII, ZnII, CdII and UO22+ complexes of 1-meotinoyl-4-phenyl-3-thiosemicarbazide (H2NTS) are reported. I.r. spectral data show that the ligand behaves in a bidentate and/or tetradentate manner. An octahedral structure is proposed for the CrII, FeII and NiII complexes; a tetrahedral structure for the MnII, CoII and Cu(NTS)·2H2O complexes; and a square planar structure for the PdII and Cu(HNTS)Cl·H2O complexes. The i.r. data suggest that the FeII complex contains a hydroxo bridge.

Flotation separation of mercury(II) from environmental water samples using thiosemicarbazide derivatives as chelating agents and oleic acid as surfactant

Abstract A simple and rapid procedure is developed for the quantitative flotation of mercury(II) from aqueous solutions. Thiosemicarbazide derivatives such as: 1-(amino-N-phenylmethanethio)-4-(pyridine-2-yl)thio-semicarbazide (H2PPS), N-phenyl-2-(pyridine-2-ylcarbamothioyl) hydrazinecarboxamide (H2PBO), 1-(amino(thioformyl)-N-phenylform)-4-(pyridine-2-yl)thiosemicarbazide (H2APO), and 1-(amino-N-(pyri-dine-3-yl)methanethio)-4-(pyridine-2-yl)thiosemicarbazide (H2PPY) are used as organic chelating agents and oleic acid (HOL) as surfactant. The different parameters affecting the flotation process namely, metal ion, ligands and surfactant concentrations, foreign ions (which are normally present in fresh and saline waters), pH and temperature are examined. Nearly 100% of mercury ions are floated at a metal:ligand ratio of 1: 4, pH ~ 4 and at room temperature (~25°C). The procedure was successfully applied to recover Hg2+ ions spiked into some water samples. A flotation mechanism is suggested based on some physical and chemical studies on the solid complexes isolated from aqueous and floated layers.

Synthesis, Spectral and Magnetic Investigation of 4-(2-pyridyl)-1-salicylaldehyde-3-thiosemicarbazone

Abstract Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and dioxouranium(VI), (UO:2 2 +), complexes of 4-(2-pyridyl)-1-salicyldehyde-3-thiosemicarbazone (H2SBT) have been synthesized and characterised by elemental analyses, molar conductance, spectral (IR, visible and NMR) and magnetic moment measurement. IR spectral data show that the ligand behaves in a bi-, tri- and/or tetradentatc manner. An octahedral structure is proposed for Cr(HSBT)2Cl.H2O. Mn(HSBT)2, Fe(HSBT)Cl2·H2O, Ni(SBT)·2H2O and Co(HSBT)2Cl·H2O, while a square-planar structure is found for Ni(H2SBT)2Cl2·2H2O, Pd(HSBT)2, Cu3(HSBT)2Cl·2H2O and Cu2(SBT)(OAc)2·2H2O.

Complexes of copper(II) with some new thiocarbamide derivatives

SummaryA new series of thiocarbamides was prepared by the reaction of benzoylisothiocyanate with various amines namely 2-aminopyridine (H2LI), 3-aminopyridine (H2LII), 2,3-diaminopyridine (H2LIII), 2,6-diaminopyridine (H2LIV), o-phenylene diamine (H2LV), p-phenylenediamine (H2LVI) and ethylene diamine (H2LVII). The copper(II) complexes of these ligands were isolated and have been characterized by elemental analyses, molar conductivities, magnetic moments and spectral (visible, i.r.) measurements. I.r. spectra show that the ligands behave as dianionic or neutral tetradentates or as monoanionic or neutral bidentates. The [Cu(HLI)Cl]2 and Cu(H2LIV)Cl2 complexes are diamagnetic and the other complexes have normal magnetic moment at room temperature. Electronic spectral analyses show that Cu2(LIV)Ac2 is planar and the other complexes are tetragonally distorted octahedral. All the complexes are non-electrolytes.

Structural, spectral, pH-metric and biological studies on mercury (II), cadmium (II) and binuclear zinc (II) complexes of NS donor thiosemicarbazide ligand.

Hg(II), Cd(II) and binuclear Zn(II) complexes derived from the tetradentate N(1)-ethyl-N(2)-(pyridine-2-yl) hydrazine-1, 2-bis (carbothioamide) ligand (H2PET) have been prepared and characterized by conventional techniques. The isolated complexes acquired the formulas, [Hg(HPET)(H2O)2Cl]⋅H2O, [Cd(HPET)Cl] and [Zn2(HPET)(PET)(OAc)]⋅H2O, respectively. IR data revealed that the ligand behaves as monobasic tridentate through (CN)py, (C-S) and new (NC)azomethine(∗) groups in both Hg(II) and Cd(II) complexes. In the binuclear Zn(II) complex, the behavior of ligand contains two types, where H2PET acts as dibasic tetradentate via (CN)py, both deprotonated (C-SH) and the new (NC)azomethine(∗) towards two Zn atoms and also it acts as monobasic tridentate via (CS), deprotonated (C-SH) and (CN)py towards the same Zn atoms. An octahedral geometry for Hg(II) complex and tetrahedral geometry for both Cd(II) and Zn(II) complexes were proposed. The bond lengths, bond angles, HOMO, LUMO and dipole moment have been calculated by DFT using materials studio program to confirm the geometry of ligand and its metal complexes. The association constant of the ligand and the stability constants of its complexes as well as the thermodynamic parameters were calculated by pH metric measurements at 298, 308 and 318K in 50% dioxane-water mixture, respectively. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. Moreover, the anti-oxidant (using ABTS and DPPH methods), anti-hemolytic, and cytotoxic activities of the compounds have been tested.