Salicylaldehyde Benzoylhydrazone Research Articles

Synthesis, characterization and antitumor activity of manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and platinum(II) complexes of 3- and 5-substituted salicylaldehyde benzoylhydrazones

Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Pt(II) with 3- and 5-substituted salicylaldehyde benzoylhydrazones (XSBH, X = H, 3-NO 2, 3-CH 3O, 5-Br, 5-Cl, 5-CH 3 or 5-NO 2) were prepared and characterized by elemental analyses, conductance measurements, magnetic moments (300−78 K) and spectral studies. On the basis of these studies the following structures are suggested: distorted octahedral for Mn(XSBH) 2, dimeric, low-spin, five- coordinate for Ni(XSBH)Cl·2H 2O, dimeric, high-spin, five-coordinate for Co(XSBH)Cl·2H 2O, dimeric four- coordinate for Zn(XSBH) and a square-planar structure for M(XSBH)Cl·H 2O (M = Cu(II) or Pt(II)). The polycrystalline ESR spectra of Cu(II) complexes are isotropic and indicate a d x2− y2 ground state in square-planar stereochemistry. All the metal(II) complexes were screened for their antitumor activity against the P388 lymphocytic leukaemia test system in mice and were found to possess no significant activity at the dosages used.

Synthesis, characterization and antitumour activity of iron(II) and iron(IlI) complexes of 3- and 5-substituted salicylaldehyde benzoyl hydrazones

Iron(II) and iron(III) complexes of tridentate ligands derived from various substituted salicylaldehydes and benzoyl hydrazones have been prepared and characterized by elemental analysis, conductance measurements, magnetic susceptibilities (from room temperature down to liquid N 2 temperature), and Mössbauer, electronic and infrared spectral studies. On the basis of these studies the following structures are suggested: monomeric, high-spin, five-coordinate for Fe(XSBH)SO 4·H 2O (XSBH = substituted salicylaldehyde benzoyl hydrazone, X = H, 3-CH 3O, 3-NO 2, 5-Cl, 5-Br, 5-CH 3 or 5-NO 2); dimeric, high-spin, phenoxide bridged, five-coordinate for Fe(H-SBH)Cl (H-SBH = salicylaldehyde benzoyl hydrazone); and monomeric, high-spin, six-coordinate for Fe(XSBH) Cl 2·H 2O (X = 3-CH 3O, 3-NO 2, 5-Cl, 5-Br, 5-CH 3 or 5-NO 2). Intermolecular antiferromagnetic exchange interaction is present in the dimeric Fe(XSBH)Cl complex, where the exchange parameter is −7.3 cm −1. The complex exhibits an asymmetrical quadrupole-split doublet in its 57Fe Mössbauer spectra. The asymmetry is found to be temperature dependent with a relatively symmetrical doublet at low temperature. All these complexes have been screened for their antitumour activity against the P388 lymphocytic leukaemia test system in mice and have been found to possess no significant activity at the dosages employed.

Syntheses of iron(III) aroyl hydrazones containing pyridoxal and salicylaldehyde. The crystal and molecular structure of two iron(III)-pyridoxal isonicotinoyl hydrazone complexes

Iron(III) complexes of three aroyl hydrazones, pyridoxal isonicotinoyl hydrazone (H 2pih), pyridoxal benzoyl hydrazone (H 2pbh), and salicylaldehyde benzoyl hydrazone (H 2sbh), were synthesized and characterized. In aqueous medium at pH 7, [Fe(pih)(Hpih)]·3H 2O is formed. In acidic methanol, a 1:1 ligand-to-metal complex is formed, [FeCl 2(H 2pih)]Cl ( 1), whereas in aqueous medium at low pH cis-[FeCl 2(H 2pih)(H 2O)]Cl·H 2O ( 2) is formed. Compounds 1 and 2 are high-spin d 5 with μ eff = 5.88 μ B and 5.93 μ B (298 K). The crystal structures of 1 and 2 show that H 2pih acts as a tridentate neutral ligand in which the phenolic and hydrazidic protons have shifted to the pyridine nitrogen atoms. The co- ordination polyhedron of 1 is ‘square’ pyramidal, whereas that of 2 is pseudo-octahedral. Compound 1 is triclinic, space group P l , with a = 12.704(2) Å, b = 8.655(2) Å, c = 8.820(2) Å, α = 105.42(1)°, β = 89.87(1)°, γ = 107.60(1)°, V = 888 Å 3, and Z = 2; 2 is monoclinic, space group P2 1/ c, with a = 15.358(4) Å, b = 7.304(3) Å, c = 17.442(4) Å, β = 101.00(2)°, V = 1921 Å 3, and Z = 4.

Structural studies of Fe(III) and Cu(II) complexes of salycylaldehyde benzoyl hydrazone, a synthetic chelating agent exhibiting diverse biological properties

Salicylaldehyde benzoyl hydrazone (SBH) is a Schiff base that can function as a tridentate chelating agent [l-3]. Some thirty years ago, it was shown that this compound has modest bacteriostatic properties when tested in vitro against microorganisms such as Mycobacten’um tuberculosis, Mycobacterium smegmatis, Candida albicans and Aspergillus niger, although these effects were not sufficiently marked to encourage further study at that time [4, 51. Recently, however, interest in the biological properties of SBH has been renewed with the recognrtion that aroylhydrazones of this type are able to induce iron excretion in mammals and thus are potentially of use in the treatment of iron overload on man [6, 71. SBH itself can mobilize iron from iron-loaded reticulocytes in vitro [8] and produces high levels of iron excretion when administered to rats [9] . preliminary studies have also shown that SBH is an unusually potent inhibitor of DNA synthesis in a variety of cultured human and rodent cells and that the complex [CuCl(SBH)]*H,O produces significant inhibition of tumor growth when given to mice bearing a transplanted fibrosarcoma [lo-121. The common mechanism underlying these various biological effects of SBH appears to be an ability to penetrate cell membranes and disrupt the intracellular metabolism of essential metal ions. The exact nature of such disruptions, and the extent to which they may be exploited for therapeutic purposes, require much additional study, including detailed elucidation of the chemical properties of complexes formed between SBH and physiologically-important transition metals. This paper reports single crystal X-ray diffraction studies of two such complexes, [FeCla(SBH)(CHsOH)] and [CuCl(SBH)]~H,O. TABLE I. Selected Bond Distances, in A.

Cytotoxic chelators and chelates 1. Inhibition of DNA synthesis in cultured rodent and human cells by aroylhydrazones and by a copper(II) complex of salicylaldehyde benzoyl hydrazone

Aroylhydrazones of pyridoxal and of salicylaldehyde, a series of tridentate chelating agents, are potent inhibitors of DNA synthesis and cell growth in a number of human and rodent cell lines grown in culture. A copper(II) complex of the most potent of the chelators, salicylaldehyde benzoyl hydrazone (SBH), exhibits significantly greater inhibitory activity than does SBH itself. Although the bioactive forms and mechanism of action of these agents are uncertain, their cytotoxic activity can equal or exceed that of many chelators and chelates previously known to possess such properties, including compounds used clinically. SBH and its copper complex are relatively non-toxic to mice and show some measure of selectivity in their effects on different cell types. It is possible that aroylhydrozones of this type and/or their metal complexes could prove to be useful therapeutic agents.