Aziza K. Shehata

SYNTHESIS AND CHARACTERIZATION OF OXOVANADIUM(IV) AND DICHLOROVANADIUM(IV)COMPLEXES OF BIOLOGICALLY ACTIVE 4-AMINOANTIPYRINE DERIVATIVES

Abstract A new series of oxovanadyl complexes of the Schiff base ligands 4-(2-pyrrolyl methyl-ideneamino)antipyrine (PyAAP), 4-(2-thienylmethylideneamino)antipyrine (TAAP), 4-furfurylidene-aminoantipyrine (FAAP) and 4-(2-hydroxybenzylideneamino)antipyrine (SAAP), have been synthesized and characterized by different physical techniques. The spectral and magnetic data indicate a distorted square pyramidal structure for all complexes. The selective deoxygenation of the oxovanadyl complexes [(PyAAP-H)2(VO)2SO4] and [(SAAP-H)2VO], which gave a good yield of the corresponding dichloro compounds [L2VCl2], L = PyAAP-H or SAAP-H, is made by using different deoxygenating agents in different solvents and at various temperatures. The purity and the percentage yield of the products are found to be solvent, temperature and deoxygenating agent dependent. Spectral and magnetic studies are used to elucidate the structure of the dichloro derivatives. The solvent effects upon the electronic spectra of the oxovanadyl complexes and the corresponding dichloro derivatives are ascertained.

Spectral, magnetic studies and molecular orbital calculations for (4,5-dimethyl-3-pyrazolyl)aldazine copper(II) complexes

SummaryA new series of copper(II) complexes derived from (4,5-dimethyl-3-pyrazolyl) aldazine (DMPA), formulated as: (a) [LCuX2]·nEtOH; (b) [LCu(H2O)](ClO4)2; and (c) [LCuX]BF4·nH2O, where n = 1/2 or 1, X = Cl or Br and L = DMPA, have been synthesized. The formulations are based on elemental analyses and molar conductivity data. I.r., u.v.-vis., e.s.r. and magnetic data reveal that the complexes are trigonal bipyramidal, tetrahedral and stacked square-planar structures for (a), (b) and (c), respectively. The trigonal bipyramidal structure for class (a) compounds is confirmed using the atom superposition and electron delocalization-molecular orbital calculations, which agree with the experimental electronic spectral data. Variable temperature magnetic susceptibility data shows a ferromagnetic interaction within copper(II) complexes of class (c).

Synthesis and spectroscopic studies on (4,5-dimethyl-3-pyrazolyl) aldazine nickel(II) complexes

Summary(4,5-Dimethyl-3-pyrazolyl)aldazine, L, reacts with nickel(II) salts to form 1∶1 and 1∶2 complexes. The 1∶1 binuclear systems involve two ligands bridging two nickels, in which L behaves as a tetradentate ligand, and the nickel(II) complexes have pseudo-octahedral stereo-chemistry. Some of the 1∶1 and 1∶2 complexes contain coordinated H2O and bridging OH. Structures of these complexes are proposed on the basis of elemental analyses, conductivity, spectral data (u.v.-vis. and i.r.) and magnetic susceptibilities.

Metal Chelates of o-Phenylenediaminb bis-Isatin Schiff Base with La(III), Ce(III), Th(IV), UO2(II), Ag(I) AND Hg(II)

Abstract A series of La(III), Ce(III), Th(IV), Uo2(II), Ag(I) and Hg(II) chelates with the Schiff base derived from isatin with o-phenylenediamine have been prepared and characterized by elemental analyses, 1H NMR, IR, UV-visible spectra and molar conductivity measurements. Analytical and other spectroscopic studies revealed that the Schiff base ligand reacts with the metal ions in 1:1 (metal : ligand) stoichiometry as dibasic tetradentate ligand through its ONNO ligating atoms. A non-electrolytic nature is suggested for these chelates except for that of Ag(I).