Ahmed A. A. Boraei

Mixed-Ligand Complexes of Some Metal Ions with N-(2-Acetamido)Iminodiacetic Acid and Salicylic Acid Derivatives: Synthesis, Solution Equilibria and Characterization Studies

Abstract The formation constants of the binary and ternary complexes formed in solution of Pb2+, Co2+, Ni2+, Cu2+, Cd2+, Ce3+ and UO2 2+ with N-(2-acetamido)-iminodiacetic acid (H2ADA) and salicylic acid derivatives [thiosalicylic (TSA) and 3,5-dinitrosalicylic acid (DNSA)] have been determined pH-metrically at t = 25 ± 0.1 °C and ionic strength μ = 0.1 mol dm−3 (KNO3) The stability of the different complexes formed are discussed in terms of the nature of the ligands and metalions. The mixed ligand complexes of the type [M2+(ADA)(TSA)] (M2+ = Co2+, Ni2+, Cu2+) were synthesized and characterized. Referee I: C. E. Barnes Referee II: J. B. Vincent

DIVALENT TRANSITION METAL ION MIXED-LIGAND COMPLEXES OF TRICINE OR GLYCYLGLYCINE AND 8-HYDROXYQUINOLINE: SYNTHESIS, CHARACTERIZATION, AND FORMATION CONSTANTS

ABSTRACT The ternary metal complexes [M(II)-(tricine or glycylglycine)-8-hydroxyquinoline], where M(II)=Co(II), Ni(II) and Cu(II), were prepared and characterized by elemental and thermogravimetric analyses as well as molar conductance, infrared and electronic spectral measurements. Formation constants of the various binary and ternary complexes formed in the systems under investigation have been determined pH-metrically [at 25°C and at constant ionic strength I=0.10 mol dm−3 (KNO3)] and are discussed in terms of the nature of both the ligand and metal ion.

Divalent transition metal ion mixed ligand complexes with aliphatic dicarboxylic acids and imidazoles

SummaryMixed ligand metal complexes of CoII, NiII and CuII with dicarboxylic aliphatic acids, H2L (succinic, malic and tartaric) as primary ligands and with imidazoles, L′ (imidazole and 2-methylimidazole) as secondary ligands were prepared and characterized. MLL′2 and ML′4 molecular formulae were suggested for these complexes were Formation constants of the different complexes were determined pH-metrically at T = 25 ± 0.1°C and μ = 0.1 mol dm−3 (NaClO4). The stability of the mixed ligand complexes increased as the effective basicity of the dicarboxylic aliphatic acid anion increased, namely, tartarate < malate < succinate acid.

SYNTHESIS AND CHARACTERIZATION OF MIXED-LIGAND COMPLEXES OF Co(II), Ni(II), and Cu(II) WITH SOME TRIAZOLES AND AMINO ACIDS

ABSTRACT Mixed‐ligand ternary metal complexes of some divalent transition metal ions [Cu(II), Ni(II) and Co(II)] with triazole compounds [1,2,4-triazole (TRZ) and 3-mercapto-1,2,4-triazole (TRZSH)] and dicarboxylic amino acids, H2L, (aspartic and glutamic ) have been synthesized. The prepared ternary chelates were characterized by elemental and thermogravimetric analyses, IR and electronic spectra as well as conductivity measurements. The general formulas [M(TRZ)(L)]H2O and H[M(TRZS)(L)H2O]H2O were found for the ternary chelates containing TRZ and TRZSH, respectively.

THE ACID IONIZATION CONSTANTS OF SOME THIAZOLIDINE COMPOUNDS: MEDIUM EFFECTS AND THERMODYNAMIC STUDIES

Abstract The pKa values of some thiazolidine compounds in various aqueous-organic solvent mixtures were determined pH-metrically at 25 °C and at an ionic strength of I = 0.02 mol dm−3 (KNO3). The organic solvents used are methanol or ethanol (as amphiprotic solvent), DMF or DMSO (as dipolar aprotic solvent), and acetonitrile (as a low basic aprotic solvent). The pK2 values obtained are discussed in terms of solvent characteristics. The pK, values of investigated compounds are increased on increasing the mole fraction of the amphiprotic or low basic aprotic organic solvent, whereas they are decreased in the presence of a dipolar aprotic solvent. Hydrogen bonding interactions and the medium basicity, in addition to the electrostatic effect, are the main factors influencing the ionization process in aqueous-amphiprotic or a low basic aprotic solvent mixture. The high stabilization of the conjugate base by dispersion forces and of the proton by its interaction with solvent as well as the solvent basicity play...

Synthesis and Spectral Characterization of Mixed Ligand Complexes of Co(II), Ni(II), and Cu(II) with 5‐Methyluracil, Amino Acids, and N‐(2‐Acetamido)iminodiacetic Acid

Abstract Mixed ligand ternary metal complexes of some divalent transition metal ions [Co(II), Ni(II), and Cu(II)] with 2,4‐dihydroxy‐5‐methylpyrimidine (5‐methyluracil, HL1) and some dicarboxylic amino acids (aspartic and glutamic, H2L2) or basic amino acids (asparagine and glutamine, HL2) as well as N‐(2‐acetamido)iminodiacetic acid as disodium salt (Na2ADA, H2L2) were prepared. The structure of the complexes was characterized by the elemental and thermal analyses, IR, and electronic spectra as well as the conductivity measurements. Six‐coordinated metal complexes were suggested for the various isolated ternary complexes of Co(II), Ni(II), and Cu(II), with molecular formulas dependent on the nature of amino acids or Na2ADA ligands (L2) present.