Oxovanadium(IV) complexes of halogenated oxines

Six VO²⁺ complexes of 8-hydroxyquinoline (oxine) and of some of its mono- and dihalogenated derivatives have been prepared. The complex of 5-chloro-oxine is very unstable and oxidizes rapidly, generating a V(V) complex of stoichiometry VO(QCl)₂OH which could also be prepared in pure form. The infrared spectra of all complexes have been recorded and are discussed in detail. The complexes containing halogenated ligands appear as polymeric species, interacting through V=O...V=O bridges. The magnetic moments, investigated at room temperature, indicate completely quenched orbital contributions. The analysis of the electronic spectra reveals very complex solution behaviour including, oxidation phenomena, ligand loss, and interaction with the solvent.Facultad de Ciencias Exacta

Synthesis and Spectroscopic Behavior of Some Oxovanadium(IV) and Oxovanadium(V) Complexes of 7-Iodo-8-Hydroxyquinoline-5-Sulfonate

The oxovanadium (IV) complex [VOL2].5H2O (1) and the oxovanadium(V) complexes K[VOL2O].4H2O) (2), [VOL2OH] (3) and [VOL2OCH3] (4) (L = potassium salt of 7-iodo-8-hydroxyquinoline-5-sulfonic acid) were prepared and characterized. The IR spectra of the solids were recorded and discussed in comparison with those of other similar compounds. The electronic absorption spectra, in different solvents, were also analyzed. Pre-resonance Raman measurements, performed with the first two mentioned complexes, reinforce some of the spectroscopic assignments.Centro de Química Inorgánic

Synthesis and Spectroscopic Behavior of Some Oxovanadium(IV) and Oxovanadium(V) Complexes of 7-Iodo-8-Hydroxyquinoline-5-Sulfonate

The oxovanadium (IV) complex [VOL2].5H2O (1) and the oxovanadium(V) complexes K[VOL2O].4H2O) (2), [VOL2OH] (3) and [VOL2OCH3] (4) (L = potassium salt of 7-iodo-8-hydroxyquinoline-5-sulfonic acid) were prepared and characterized. The IR spectra of the solids were recorded and discussed in comparison with those of other similar compounds. The electronic absorption spectra, in different solvents, were also analyzed. Pre-resonance Raman measurements, performed with the first two mentioned complexes, reinforce some of the spectroscopic assignments.Centro de Química Inorgánic

Thermal behaviour of oxovanadium(IV) complexes of halogenated derivatives of 8-hydroxyquinoline

The thermal behaviour of a series of oxovanadium(IV) complexes of halogenated derivatives of 8-hydroxyquinoline was investigated by means of TG and DTA measurements in oxygen atmosphere. V2O5 was the final pyrolysis residue in all cases.Centro de Química Inorgánic

Mean Amplitudes of Vibration of Chromyl Bromide

Mean amplitudes of vibration of CrO2Br2 in the temperature range between 0 and 1000 K have been calculated from recently reported spectroscopic data. The results are briefly discussed and compared with those of CrO2F2 and CrO2Cl2.Centro de Química Inorgánic

Synthesis and Spectroscopic Behavior of Some Oxovanadium(IV) and Oxovanadium(V) Complexes of 7-Iodo-8-Hydroxyquinoline-5-Sulfonate

The oxovanadium (IV) complex [VOL2].5H2O (1) and the oxovanadium(V) complexes K[VOL2O].4H2O) (2), [VOL2OH] (3) and [VOL2OCH3] (4) (L = potassium salt of 7-iodo-8-hydroxyquinoline-5-sulfonic acid) were prepared and characterized. The IR spectra of the solids were recorded and discussed in comparison with those of other similar compounds. The electronic absorption spectra, in different solvents, were also analyzed. Pre-resonance Raman measurements, performed with the first two mentioned complexes, reinforce some of the spectroscopic assignments.Centro de Química Inorgánic

Oxovanadium(IV) complexes of halogenated oxines

Six VO²⁺ complexes of 8-hydroxyquinoline (oxine) and of some of its mono- and dihalogenated derivatives have been prepared. The complex of 5-chloro-oxine is very unstable and oxidizes rapidly, generating a V(V) complex of stoichiometry VO(QCl)₂OH which could also be prepared in pure form. The infrared spectra of all complexes have been recorded and are discussed in detail. The complexes containing halogenated ligands appear as polymeric species, interacting through V=O...V=O bridges. The magnetic moments, investigated at room temperature, indicate completely quenched orbital contributions. The analysis of the electronic spectra reveals very complex solution behaviour including, oxidation phenomena, ligand loss, and interaction with the solvent.Facultad de Ciencias Exacta

Synthesis, chemical speciation and SOD mimic assays of tricarballylic acid-copper(II) and imidazole-tricarballylic acid-copper(II) complexes

The coordination behavior of copper(II) with tricarballylic acid (H3TCA) and imidazole (Imz) is described. Speciation in aqueous solution has been determined at 25 C and 0.15 M NaCl ionic strength by potentiometric measurements and EPR characterization of the species. Two new compounds CuTCAH 3H2O and CuTCAHImz 2H2O were obtained and characterized by elemental analysis diffuse reflectance, FTIR (Fourier transform infrared spectroscopy), EPR and thermal behavior. Their in vitro superoxide dismutase- mimetic activities have been tested.Centro de Química Inorgánic

Thermal behaviour of oxovanadium(IV) complexes of halogenated derivatives of 8-hydroxyquinoline

The thermal behaviour of a series of oxovanadium(IV) complexes of halogenated derivatives of 8-hydroxyquinoline was investigated by means of TG and DTA measurements in oxygen atmosphere. V2O5 was the final pyrolysis residue in all cases.Centro de Química Inorgánic

Model complexes with naturally occurring ligands (salicylglycine and imidazol) and the biometals copper and cobalt

Two new complexes [Cu(Imz)4Cl2][Cu(Imz)4Cl] 2(2-OH-Hip)2 (1) and [Co(2-OH-Hip)(Imz)3] H2O (2) (with Imz¼Imidazol and 2-OH-Hip¼2-hydroxyhippuric acid) were prepared and characterized. The molecular structures and the solution and solid state behavior of the complexes were investigated. Complex 1 crystallizes in the monoclinic space group P21=c with a ¼ 16:880ð1Þ, b ¼ 8:046ð1Þ, c ¼ 24:683ð1Þ A, b ¼ 107:88ð1Þ , and Z ¼ 2, while complex 2 crystallizes in the orthorhombic space group Pbca with a ¼ 11:712ð2Þ, b ¼ 15:741ð4Þ, c ¼ 22:254ð4Þ A, and Z ¼ 8. The [Cu(Imz)4Cl2][Cu(Imz)4Cl]2(2-OH-Hip)2 solid consists in two distinct monomeric Cu(II) complexes: one of them is neutral octahedral [Cu(Imz)4Cl2] and the other, charged square basis pyramida [Cu(Imz)4Cl]þ. The 2-hydroxyhippuric acid, which here acts as a counter ion, is deprotonated at its carboxylic group. Cobalt(III) ion in [Co(2-OH-Hip)(Imz)3] H2O is at the center of an octahedral environment, coordinated to three Imidazol ligands and to a triply deprotonated 2-hydroxyhippuric acid molecule acting as a tridentate ligand. Aqueous solution equilibrium of the quaternary system Cu2þ/2-OH-Hip/Imz/Hþ was studied by potentiometric titrations.Centro de Química Inorgánic