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

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

Characterization of biominerals in species of <i>Canna</i> (Cannaceae)

Plant biominerals are not always well characterized, although this information is important for plant physiology and can be useful for taxonomic purposes. In this work, fresh plant material of seven wild neotropical species of genus Canna, C. ascendens, C. coccinea, C. indica, C. glauca, C. plurituberosa, C. variegatifolia and C. fuchsina sp. ined., taken from different habitats, were studied to characterize the biominerals in their internal tissues. For the first time, samples from primary and secondary veins of leaves were investigated by means of infrared spectroscopy, complemented with X-ray powder diffractometry and scanning electron microscopy. The spectroscopic results, supported by X-ray powder diffractometry, suggest that the calcium oxalate is present in the form of whewellite (CaC2O4×H2O) in all the investigated samples. It is interesting to emphasize that all IR spectra obtained were strongly similar in all species studied, thus indicating an identical chemical composition in terms of the biominerals found. In this sense, the results suggest that the species of Canna show similar ability to produce biogenic silica and produce an identical type of calcium oxalate within their tissues. These results can be an additional trait to support the relationship among the families of Zingiberales.Facultad de Ciencias Naturales y Muse

Crystal and molecular structure and spectroscopic behavior of isotypic synthetic analogs of the oxalate minerals stepanovite and zhemchuzhnikovite

The crystal structure of synthetic stepanovite, Na[Mg(H₂O)₆][Fe(C₂O₄)₃]·3H₂O, and zhemchuzhnikovite, Na[Mg(H₂O)₆][Al0.55Fe0.45(C₂O₄)₃]·3H₂O, has been determined by single-crystal X-ray diffraction methods. The compounds are isotypic to each other and to the previously reported Na[Mg(H₂O)₆][M(C₂O₄)₃]·3H₂O (M: Cr, Al). They crystallize in the trigonal P3c1 space group with Z = 6 molecules per unit cell and (hexagonal axes) a = 17.0483(4), c = 12.4218(4) Å for the iron compound, and a = 16.8852(5), c = 12.5368(5) Å for the Al/Fe solid solution. Comparison of our crystallographic results with previous X-ray diffraction and chemical data of type stepanovite and zhemchuzhnikovite minerals provides compelling evidence that these natural materials possess the same crystal and molecular structure as their synthetic counterparts. It is shown that the originally reported unit cell for stepanovite represents a pronounced sub-cell and that the correct unit cell and space group are based on weak superstructure reflections. The infrared and Raman spectra of both synthetic analogs were also recorded and are briefly discussed.Facultad de Ciencias ExactasInstituto de Física La PlataCentro de Química Inorgánic