M. E. Khalifa

Synthesis of mono and binuclear complexes of α-oximinoacetoacetanilide-4-phenylthiosemicarbazone

Transition metal complexes of α-oximinoacetoacetanilide-4-phenylthiosemicarbazone (H3AT) have been synthesized. Attempts were made to elucidate their geometries by elemental and thermal analyses, molar conductance, magnetic measurements and spectroscopy (IR and electronic). All the investigated metal ions form mononuclear complexes except the Cu(II) and Fe(III) ions which form binuclear complexes. The ligand behaves as a binegative tridentate species and coordinates via the thiol sulfur and azomethine nitrogens of the oxime and thiosemicarbazone moieties with Cu(II), Ni(II) and Pd(II) ions, and as a trinegative tridentate species with Fe(III) ion forming a sulfur bridge. The loss of thiol and oxime hydrogens is confirmed by the pH titrations of H3AT and its metal(II) complexes against 0.01 M NaOH. The protonation constants (log K1 H=10.7 and log K1 H = 6.6) were calculated as well as the stability constants of the metal complexes. The ligand may be applied as analytical reagent for the spectrophotometric determination of Ni(II), Co(II), Cu(II) and Pd(II) ions in the 0.5–3 ppm range. The Cu(II), Ni(II) and Pd(II) complexes possess square-planar stereochemistry. Co(II) salts form two types of complexes; one is diamagnetic, due to complete oxidation to Co(III), the other is paramagnetic with a subnormal magnetic moment due to partial oxidation of Co(II). The ligand field parameters were calculated for the two complexes.

Ligational Behaviour of 1-Picolinoyl–4-phenyl–3-thiosemicarbazide (H2PTS) Towards Some Transition Metal Ions

Abstract Complexes of 1-picolinoly-4-phenyl-3-thiosemicarbazide (H2PTS) with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and UO2(VI) have been synthesized and characterized on the basis of elemental analyses, molar conductivities, magnetic moment and spectral (IR and visible) studies. IR spectral data show that H2PTS behaves in a monoanionic bidentate or tetradentate and bianionic tetradentate manner. All complexes are non-electrolytes. An octahedral structure is proposed for the Cr(III), Mn(II), Fe(III), Co(II) and Ni(II) complexes, while a square-planar one is suggested for Cu(HPTS)Cl.H2O and Cu(PTS) according to the data of magnetic and electronic spectral measurements.

Synthesis and Spectroscopic Studies of Some Metal Complexes Derived from 4-Phenyl-1-Pipridine-3-Thiosemicarbazide (PPTS)

Abstract The reaction of 4-phenyl-1-pipridine-3-thiosemicarbazide (PPTS) with some hydrated metal salts of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and U(VI)O2 affords complexes of the types M(HL)Cl.H2O (M [dbnd] Co(II), Ni(II), Cu(II) or Cd(II)), Cd(HL)2.3H2O, M(L).nH2O (M [dbnd] Mn(II), Zn(II) or U(VI)O2, n = O-5), CuI(HL) and Hg(H2L)Cl2 (H2L = PPTS). Elemental analyses, molar conductivities, magnetic measurements and spectra (IR, visible) have been used to characterize the structure of the isolated solid complexes. The infrared spectra show that the free ligand (PPTS) coordinates either in the keto or enol form and behaves in a bidentate manner but with different modes of bonding. The spectral and magnetic studies suggest a tetrahedral geometry for both Co(II) and Ni(II) and a pseudo-tetrahedral structure for the Cu(II) complex. Also, the ligand acts as a reducing agent giving a diamagnetic complex as in case of CuI (HL).

Spectrophotometric determination of phosphate with alizarin red sulphonate

Abstract The formation of complexes between orthophosphate and alizarin red sulphonate (ARS) has been ascertained. One or two kinds of complexes are formed in solution according to the pH of the medium with PO3−4:ARS ratios of 1:3 and 1:2 at pH 6.6 and 8.3 with formation constants of 2.97 × 1020 and 1.3 × 109 at λmax 478 and 520 nm, respectively. The development of the 1:3 complex was utilized for the determination of orthophosphate with a working concentration range of 0.03–6.00 μg ml−1 phosphorus (ϵ = 1.14 × 104 l mol−1 cm−1 at 478 nm). The interference of some anions and cations was investigated. Structures of the isolated solid complexes are suggested based on elemental analysis and infrared spectrophotometric measurements. A procedure for the determination of different forms of phosphorus has been elaborated and applied to differentiate between non-organic and organically bound phosphorus in re-used water effluents.

Synthesis, Spectral and Magnetic Investigations on 4-Benzamidothiosemicarbazone Complexes

Abstract The synthesis of new complexes of Ni(II), Co(II), Cu(II), Zn(II), Cd(II) and Hg(II) with thiosemicarbazones derived from 4-benzamidothiosemicarbazide and 4-acetylpyridine (BACPT) or 3-pyridine aldehyde (BPAT) are reported. These complexes have been characterized by elemental analyses, molar conductivities, magnetic moments and spectral (visible, u.v., i.r.) studies. I.R. spectra show that BPAT acts as a monovalent or neutral bidentate ligand while BACPT behaves in a monovalent bidentate, tridentate and neutral tetradentate manner. The magnetic and electronic spectral data confirmed that the copper complexes of BACPT are diamagnetic while that of BPAT is paramagnetic, the Co(II) complex of BACPT has an octahedral structure while that of BPAT has a tetrahedral structure and the Ni(II) complexes of both ligands have octahedral structures. The molar conductivities for all complexes are reported in the range of non-electrolytes except that of the copper complex of BPAT which suggest that it is a 1:1 e...

Synthesis and Spectroscopic Studies on Novel Transition Metal Complexes of 3-Oximjno-3-(2-Pyridylcarbamoyl)Propane-2-One

Abstract New transition metal complexes of 3-oximino-3-(2-pyridyl-carbamoyl)propane-2-one (H2OPP) have been prepared and characterized by conventional physical and chemical methods. The ligand chelates in the keto form in its reaction with the investigated metal salts except for Cu(II) ions with which it reacts in the end form. Copper(II) acetate forms a binuclear complex of the formula [Cu2(OPP)(AcO)2(H2O)2] while Cu(II) chloride forms a mononuclear complex of the formula [Cu(HOPP)Cl.H2O]H2O. This complex is a non-electrolyte in dimethylsulfoxidc solution and a 1:1 electrolyte in aqueous solution. This change in structure with the change in solvent may be due to the possible formation of a hydrate isomer [Cu(HOPP)(H2O)2]Cl. The geometries of the formed complexes have been elucidated on the basis of magnetic and spectral studies. The thermal decomposition of [Cu(HOPP)Cl.H2O]H2O and [Fe(H2OPP)2Cl2]Cl was investigated. Stoichiometric calculations from the obtained thermograms strongly confirmed the proposed...

Synthesis and Structural Studies of Butylmalonyl-bis(4-phenylsemicarbazide) Complexes

Abstract New transition metal complexes of CoII, NiII, CuII and FeIII with butylmalonylbis(4-phenylsemicarbazide), H4BMPS, have been synthesized chemically and electrochemicaly. Attempts have been made to ascertain their probable structures on the basis of elemental analyses, molar conductivity, spectra (IR, electronic and 1H NMR) and magnetic measurements. IR data show that H4BMPS acts as a bidentate or hexadentate (with two metal ions) ligand coordinating via different modes. The stereochemistry of the CoII, NiII, CuII and FeIII complexes was investigated with the help of magnetic and spectral studies. The crystal field parameters calculated for the CoII and NiII complexes agree fairly well with that reported for known octahedral complexes. [Co2(BMPS)(H2O)4] has a trigonal bipyramidal structure while [Ni2(BMPS)(H2O)4] has mixed stereochemistry.

Chemical and Electrochemical Synthesis of Transition Metal Complexes of Butylmalonic Acid Dihydrazide and its Salicyloyl Hydrazone

Abstract Iron, cobalt, nickel and copper complexes of butylmalonic acid dihydrazide (H2BMD) and its salicyloylhydrazone (H4BMS) have been prepared by interaction of the ligands with the metal salt solutions or by direct electrochemical oxidation of the metal in acetone solution of the ligand. Higher yields (85-90%) were obtained by the electrochemical method. IR spectra show that H2BMD and H4BMS behave as neutral or binegative ligands binding in a bidentate, tridentate and/or tetradentate manner, depending on the preparative conditions. Different (octahedral, tetrahedral and square-planar) geometries are suggested for the isolated complexes based on magnetic and electronic spectral studies. The ligand field parameters of the Co(II) and Ni(II) complexes were calculated and the variation of their values with the change of coordination sites is discussed.