Showing papers by "Enrique J. Baran published in 2003"
TL;DR: In this paper, a large series of ternary oxides of composition A 2 BB′O 6 and belonging to the perovskite structural type have been prepared and their structures confirmed by X-ray powder diffractometry.
82 citations
TL;DR: In this article, the results of their own studies, as well as those of other research groups, on models related to different aspects of its metabolism and detoxification and to vanadium dependent haloperoxidases are presented.
Abstract: Increasing evidence on the need of the higher forms of life for vanadium has accumulated during recent years. Model studies have become a very important tool to attain a better understanding of different aspects of the biochemistry of this bioelement. In this account we present the results of our own studies, as well as those of other research groups, on models related to different aspects of its metabolism and detoxification and to vanadium dependent haloperoxidases. Additional information about the interaction of the biologically relevant oxovanadium(IV) cation with important bioligands, such as nucleotides, carbohydrates, phosphates and related systems are also presented.
37 citations
TL;DR: The crystal structures of [Cd(tsac)2(im)2] (1) (tsac=anion of thiosaccharine; im=imidazole) and of (Him)[cd(tac)3(H2O)] (2) (imizolium cation) have been determined at 120 K by single crystal X-ray diffractometry as discussed by the authors.
37 citations
TL;DR: The molecular structure of [Cu(sulfadimet)(2)].SO(CH(3))(2) (sulf adimethoxine=4-p-aminobenzenesulfonamido-2,6-dimethoxypyrimidine) was determined by single crystal X-ray diffractometry by determining the structural peculiarities of the complex.
29 citations
TL;DR: In this article, two novel Cu(II)-dipeptide complexes containing l -histidyl- l -glycine and l - histidyl− l -alanine as ligands were prepared and characterised by infrared and electronic spectroscopies.
27 citations
TL;DR: The electrochemical properties and the stability of the CrIII/CrII complexes were investigated in DMF solutions by cyclic voltammetry, and complemented by electronic spectroscopy as mentioned in this paper.
Abstract: The electrochemical properties and the stability of the CrIII complexes [Cr(pic)3]·H2O and [Cr(pic)2(OH)]2·5H2O (Hpic = pyridine-2-carboxylic acid = picolinic acid) were investigated in DMF solutions by cyclic voltammetry, and complemented by electronic spectroscopy. The electrochemical results indicate that both compounds undergo a one-electron reversible reduction process. The mononuclear species has a more accessible reduction potential than the binuclear one. In this last case, the observed one-electron process can be ascribed to a considerable stabilization of the mixed valence CrIII/CrII species. Both complexes were also characterized by infrared and Raman spectroscopy.
Voltammetrische und spektrospische Untersuchung von Chrom(III)/Picolinat Komplexen
Das elektrochemische Verhalten und die Stabilitat der CrIII-Komplexe [Cr(pic)3]·H2O und [Cr(pic)2(OH)]2·5H2O (Hpic = Pyridin-2-Carboxyl-Saure = Picolin- Saure) wurde in DMF Losung durch cyklische Voltammetrie untersucht und durch Elektronenspektroskopie erganzt. Die elektrochemischen Ergebnisse zeigen, dass in beiden Verbindungen ein umkehrbarer Ein-Elektron-Reduktionsprozess stattfindet. Die mononukleare Spezies hat ein geringeres Reduktionspotential als die zweikernige. Der in diesem letzten Fall beobachtete Ein-Elektron-Prozess lasst sich durch eine betrachtliche Stabilisierung der gemischten-Valenz CrIII/CrII-Spezies erklaren. Beide Komplexe wurden auch mittels Infrarot und Raman Spektroskopie charakterisiert.
27 citations
TL;DR: General aspects related to the essentiality of inorganic systems in living organisms are presented, followed by a detailed discussion of the supplementation of iron, copper, zinc, chromium, selenium, magnesium and some other minor trace elements.
Abstract: Supplementation of essential trace elements has become an increasingly important field of research in modern pharmacology. The present review presents general aspects related to the essentiality of inorganic systems in living organisms, followed by a detailed discussion of the supplementation of iron, copper, zinc, chromium, selenium, magnesium and some other minor trace elements. Some recent advances in this field as well as future challenges and perspectives are also discussed.
25 citations
TL;DR: In this paper, the crystal structures of two Thallium(I)-Thiosaccharinat-Komplexes have been determined at 116 K by single crystal X-ray diffractometry.
Abstract: The crystal structures of [Tl(tsac)] (1) and [Tl(tsac)(ophen)] (2) (tsac = anion of thiosaccharin; ophen = 1, 10 phenanthroline) have been determined at 116 K by single crystal X-ray diffractometry. Complex 1 crystallizes in the monoclinic space group P21/a with Z = 4 and complex 2 in the monoclinic space group C2/c with Z = 8.In both complexes TI is coordinated to a thiosaccharinate anion through its sulphur and nitrogen atoms. A distorted eight fold coordination sphere around the cation in complex 1 is completed with two other longer Tl-S bonds and four Tl···O contacts with five symmetry related neighbouring thiosaccharinate anions. A phenanthroline molecule acting as a bidentate ligand through its nitrogen atoms completes a four-fold coordination around the metal atom in complex 2. The infrared spectra of both complexes were also recorded and their most important features discussed on the basis of its structural peculiarities.
Kristallographische und spektroskopische Charakterisierung von zwei neuen Thallium(I)-Thiosaccharinat-Komplexen
Die Kristallstrukturen von [Tl(tsac)] (1) und [Tl(tsac)(ophen)] (2) (tsac = Anion von Thiosaccharin; ophen = 1, 10 Phenanthrolin) wurden rontgenographisch, bei 116 K, an Einkristallen bestimmt. Komplex 1 kristallisiert in der monoklinen Raumgruppe P21/a mit Z = 4 und Komplex 2 in the monoklinen Raumgruppe C2/c mit Z = 8. In beiden Komplexen ist TlI an ein Thiosaccharinat-Anion uber das Schwefel- und das Stickstoffatom koordiniert. Im Komplex 1 ist eine verzerrte achtfache Koordinationssphare um das TlI Ion zu erkennen, welche durch zwei weitere und langere Tl-S-Bindungen und vier Tl···O-Kontakte, die von funf weiteren symmetrie-bezogenen Thiosaccharinat-Ione, stammen. Im Komplex 2 wird die vierfache Koordinationssphare um das Kation durch ein Phenanthrolin-Molekul erweitert, welches als zweizahniger Ligand uber seine Stickstoffatome fungiert. Die Infrarotspektren beider Komplexe wurden aufgenommen und ihre wichtigsten Aspekte an Hand der Strukturbesonderheiten analysiert.
18 citations
TL;DR: In this paper, the infrared and Raman spectra of the title complex were recorded and assignments for the VO + 2, PO 3 - 4 and V-O and V -N skeletal vibrations are proposed.
Abstract: The infrared and Raman spectra of the title complex were recorded and assignments for the VO + 2 , PO 3 - 4 and V-O and V -N skeletal vibrations are proposed. The results are of interest in relation to the vibrational-spectroscopic properties of the active site of vanadium haloperoxidases.
8 citations
TL;DR: Mean amplitudes of vibration of the halogen molecules F 2, Cl 2, Br 2, and I 2 have been calculated from known spectroscopic data in the temperature range between 0 and 1000 K as mentioned in this paper.
Abstract: Mean amplitudes of vibration of the halogen molecules F 2 , Cl 2 , Br 2 , and I 2 have been calculated from known spectroscopic data in the temperature range between 0 and 1000 K. The results are briefly discussed, and some comparisons with the results of the related diatomic interhalogen molecules, as well as with experimental values obtained by electron diffraction experiments, are made.
5 citations
TL;DR: In this paper, the authors compared the bond characteristics of the full series of the trihydrides of group-15 elements and showed that Sb-H bonds are somewhat stronger than Bi-H bond, whereas deformational constants are comparable.
Abstract: .Inthis case the structural parameters and vibrational fre-quencies were taken from the paper of Fusina et al. [5](cf. also [7]). The results are included in Table 1.As can be seen, Sb-H bonds are somewhat strongerthan Bi-H bonds, whereas the deformational constantsare comparable. In both cases interaction constants arenegligible. The potential energy distribution of bothmolecules showed that all the vibrations are highlycharacteristic, as expected for species with heavy cen-tral atoms.With the now obtained results it is interesting tocompare the bond characteristics of the full series ofthe trihydrides of group-15 elements. A plot of theforce constants of the X-H bonds as a function of theatomic number is presented in Fig. 1 (the force con-stants of the three lighter trihydrides were taken fromthe book of Siebert [8]). From this figure it becomes
01 Jan 2003
TL;DR: In this article, the magnetic behavior of 2H2O was investigated by magnetic susceptibility measurements in the temperature range between 2 and 300 K, complemented with ESR (Q- and Xband) spectra.
Abstract: SUMMARY. The recently reported mixed metal glutamate complex of stoichiometry [CuMg(Lglu)2(H2O)3].2H2O was obtained as microcrystalline powder from aqueous solution. Its structure was confirmed by X-ray diffractometry. The infrared spectrum of the complex was recorded and briefly discussed in relation to its structural characteristics. Its magnetic behavior was investigated by magnetic susceptibility measurements in the temperature range between 2 and 300 K, complemented with ESR (Q- and Xband) spectra. These measurements confirmed a certain magnetic interaction between the Cu(II) centers present in the polymeric structure of the compound. The study was completed with a series of dissolution tests, which confirmed the potential usefulness of this complex for metal supplementation in human and veterinary medicine. RESUMEN. “ Propiedades Vibracionales y Magne ticas de un Complejo deCu/Mg con Glutamato” . El complejo metalico mixto de glutamato recientemente descripto, de estequiometr ia [CuMg(L-glu)2(H2O)3].2H2O, fue obtenido en forma de polvo microcristalino de soluci o n acuosa. Su estructua fue confirmada por difracci o n de rayos X. El espectro de infrarrojo del complejo fue registrado y discutido brevemente en base a sus peculiaridades estructurales. Su comportamiento magne tico se investigo a trave s de mediciones de susceptibilidad magne tica en el intervalo de temperaturas entre 2 y 300 K, complementadas con espectros ESR (en bandas Q y X). Estas medidas confirmaron una cierta interacci o n entre los centros de Cu(II) presentes en la estructura polim e rica del compuesto. El estudio se completo con una serie de ensayos de disoluci o n, los que confirmaron la potencial utilidad de este complejo para la suplementacio n de metales en medicina humana y veterinaria.
TL;DR: The mean amplitudes of vibration of the hexafluoroanions of the groups 5 and 15 of the Periodic System have been calculated from known spectroscopic data between 0 and 1000 K.
Abstract: The mean amplitudes of vibration of the hexafluoroanions of the groups 5 and 15 of the Periodic System have been calculated from known spectroscopic data between 0 and 1000 K. Bond peculiarities of these compounds are discussed, and some comparisons with related species are made.