The ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions

<p>Abstract</p> <p>Background</p> <p>The heterocyclic hydrazones constitute an important class of biologically active drug molecules. The hydrazones have also been used as herbicides, insecticides, nematocides, redenticides, and plant growth regulators as well as plasticizers and stabilizers for polymers. The importance of the phenolic quinolyl hydrazones arises from incorporating the quinoline ring with the phenolic compound; 2,4-dihydroxy benzaldehyde. Quinoline ring has therapeutic and biological activities whereas, phenols have antiseptic and disinfectants activities and are used in the preparation of dyes, bakelite and drugs. The present study is planned to check the effect of the counter anions on the type and geometry of the isolated copper(II)- complexes as well as the ligational behavior of the phenolic hydrazone; 4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono)methyl] benzene-1,3-diol; (H₂L).</p> <p>Results</p> <p>A phenolic quinolyl hydrazone (H₂L) was allowed to react with various copper(II)- salts (Cl‾, Br‾, NO₃‾, ClO₄‾, AcO‾, SO₄^2-). The reactions afforded dimeric complexes (ClO₄‾, AcO‾ ), a binuclear complex (NO₃‾ ) and mononuclear complexes (the others; Cl‾, Br‾, SO₄^2-). The isolated copper(II)- complexes have octahedral, square pyramid and square planar geometries. Also, they reflect the strong coordinating ability of NO₃‾, Cl‾, Br‾, AcO‾ and SO₄^2-anions. Depending on the type of the anion, the ligand showed three different modes of bonding <it>viz</it>. (NN)⁰for the mononuclear complexes (<b>3, 4, 6</b>), (NO)^-with O- bridging for the dimeric complexes (<b>1, 5</b>) and a mixed mode [(NN)⁰+ (NO)^-with O- bridging] for the binuclear nitrato- complex (<b>2</b>).</p> <p>Conclusion</p> <p>The ligational behavior of the phenolic hydrazone (H₂L) is highly affected by the type of the anion. The isolated copper(II)- complexes reflect the strong coordinating power of the SO₄^2-, AcO‾, Br‾, Cl‾ and NO₃‾ anions. Also, they reflect the structural diversity (octahedral, square pyramid and square planar) depending on the type of the counter anion.</p

The ligational behavior of an isatinic quinolyl hydrazone towards copper(II)- ions

<p>Abstract</p> <p>Background</p> <p>The importance of the isatinic quinolyl hydrazones arises from incorporating the quinoline ring with the indole ring. Quinoline ring has therapeutic and biological activities whereas, the indole ring occurs in Jasmine flowers and Orange blossoms. As a ligand, the isatin moiety is potentially ambidentate and can coordinate the metal ions either through its lactam or lactim forms. In a previous study, the ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions has been studied. As continuation of our interest, the present study is planned to check the ligational behavior of an isatinic quinolyl hydrazone.</p> <p>Results</p> <p>New homo- and heteroleptic copper(II)- complexes were obtained from the reaction of an isatinic quinolyl hydrazone (HL) with several copper(II)- salts <it>viz. </it>Clˉ, Brˉ, NO₃ˉ, ClO₄^-, SO₄^2-and AcO^-. The obtained complexes have O_h, T_dand D_4h- symmetry and fulfill the strong coordinating ability of Clˉ, Brˉ, NO₃ˉ and SO₄^2-anions. Depending on the type of the anion, the ligand coordinates the copper(II)- ions either through its lactam (NO₃ˉ and ClO₄^-) or lactim (the others) forms.</p> <p>Conclusion</p> <p>The effect of anion for the same metal ion is obvious from either the geometry of the isolated complexes (O_h, T_dand D_4h) or the various modes of bonding. Also, the obtained complexes fulfill the strong coordinating ability of Clˉ, Brˉ, NO₃ˉ and SO₄^2-anions in consistency with the donor ability of the anions. In case of copper(II)- acetate, a unique homoleptic complex (<b>5</b>) was obtained in which the AcO^-anion acts as a base enough to quantitatively deprotonate the hydrazone. The isatinic hydrazone uses its lactim form in most complexes.</p

Studies of Bivalent Metal Complexes of p-Chloro- & p-Methoxy-benzylidene- 4-phenylthiosemicarbazone

766-76

Synthesis and characterization of transition metal complexes containing oxime, amido and thioamido groups

92-97New transition metal complexes of α-oximinoaceto-o-anisidide- 4-phenylthiosemicarbazone(H3OAAT) have been prepared and their geometrics are assigned. All the investigated complexes are mononuclear except the Cu(II) ions which form binuclear complexes with the chloride and acetate salts. The ligand acts as binegative tridentate in the Co (II), Ni(II), Zn(II) and Pd (II) complexes, trinegative tridentate in the Fe(III) and Co(III) complexes and trinegative pentadentate manner in the Cu(II) complexes. The Cu(II) and Pd(II) complexes possess a squareplanar stereochemistry while Ni(II) complex has an octahedral structure.Co(II) salts form diamagnetic and paramagnetic complexes. The protonat ion constants of the ligand and the stability constants of its Co(II), Ni (II) and Cu(II) complexes are calculated pH-metrically. Moreover, H3OAAT has been applied for the determination of Ni (II), Co(II), Cu(III) and Pd(II) ions in the 0.1-3.5 ppm range

Ligational Behaviour of a Bridging Tetradentate NONO Donor Ligand Towards Co (II), Ni(II), Cu(II), Zn(II) & Cd(II)

1057-105

Synthesis, spectroscopic characterization, molecular modeling and eukaryotic DNA degradation of new hydrazone complexes

2,5-Hexanedione bis(salicyloylhydrazone) [H4L] formed novel complexes with some transition metal ions. H4L and its complexes were characterized by elemental analyses, spectral (IR, 1H NMR, ESR and MS), thermal and magnetic measurements. The complexes have the formulae [VO(H2L)]·2H2O, [Ni(H2L)]·3H2O, [Zn(H2L)], [Ni(H4L)Cl2]·2H2O and [Cr2(H2L)(OAc)2(OH)2]–·2H2O, [Cu(H4L) (H2L)(EtOH)2]·2H2O, [Co2(H2L)(OAc)2]·H2O, [Mn2(H2L)–(OH)2]·H2O [Cu2(H2L)(OAc)2(H2O)6], and [Co2(H2L)(H2O)4Cl2]·2H2O. H4L released its OH or NH protons during the complex formation. Acetate and hydroxo groups bridged the two chromium in [Cr2(H2L)(OAc)2(OH)2]·2H2O. The magnetic moments and electronic spectra of all complexes provide: tetrahedral for [Co2(H2L)(OAc)2]·H2O, [Ni(H2L)]·3H2O and [Zn(H2L)]; square-pyramidal for [VO(H2L)]·2H2O and octahedral for the rest. In DMF solution, the bands are shifted to higher energy suggesting a weak interaction with the solvent. The ESR spectra support the mononuclear geometry for [VO(H2L)]·2H2O and [Cu(H3L)2(EtOH)2]·2H2O. The thermal decomposition of the complexes revealed the outer and inner solvents as well as the end product which in most cases is metal oxide