Enrique J. Baran

Bio: Enrique J. Baran is an academic researcher from National University of La Plata. The author has contributed to research in topics: Infrared spectroscopy & Raman spectroscopy. The author has an hindex of 32, co-authored 589 publications receiving 6392 citations. Previous affiliations of Enrique J. Baran include Technical University of Dortmund & National Scientific and Technical Research Council.

Synthesis and spectroscopic behavior of some oxovanadium(IV) and oxovanadium(V) complexes of 7-iodo-8-hydroxyquinoline-5-sulfonate

Abstract: O complexo de oxovanadio(IV) [VOL2].5H2O (1) e os complexos de oxovanadio(V) K[VOL2O].4H2O) (2), [VOL2OH] (3) e [VOL2OCH3] (4) (L = sal de potassio do acido 7-iodo-8-hidroxiquinolina-5-sulfonico) foram preparados e caracterizados. Os espectros no infravermelho dos solidos foram discutidos e comparados com os de outros compostos semelhantes. Os espectros eletronicos, obtidos em diferentes solventes, tambem foram analisados. Medidas de Raman pre-ressonante dos dois primeiros compostos mencionados acima fortalecem algumas das atribuicoes espectroscopicas.

Vibrational spectrum of Zn2 VO(PO4)2

Abstract: The infrared and laser Raman spectra of Zn 2 VO(PO 4 ) 2 were recorded and are briefly discussed with the aid of a factor group analysis. Some interesting aspects related to the strongly condensed nature of the phosphate groups and to the characteristics of the V=O bonds in this structure are also considered

Vibrational spectra of polaprezinc, a polymeric Zn(II) complex of carnosine

Abstract: Polaprezinc, the Zn(II) complex of the dipeptide carnosine (β-alanyl histidine) presents an interesting biological and pharmacological activity, specially as an anti-ulcer agent. The infrared and Raman spectra of this compound were recorded and briefly discussed. Some comparisons were made with related complexes and with free carnosine. The results confirm the coordination environment of the Zn(II) cation, constituted by the terminal amino N-atom, the deprotonated amide N-atom and one carboxylate oxygen of one dipeptide molecule and the N-atom of the imidazole moiety of a second carnosine molecule. Copyright © 2007 John Wiley & Sons, Ltd.

New Saccharinato/Ammonia Complexes of Nickel(II) and Zinc(II). A Structural and Spectroscopic Study

Abstract: Two new saccharinate/NH3 complexes of composition [Ni(sac)2(NH3)4] and [Zn(sac)2(NH3)2] were obtained and their crystal structures determined by single crystal X-ray diffractometry. The elongated octahedral NiII complex crystallizes in the monoclinic P21/c space group with Z = 2 whereas the tetrahedral ZnII complex is triclinic (space group and Z = 2). For [Ni(sac)2(NH3)4] the magnetic moment and electron absorption spectrum were obtained and discussed. The infrared spectra of both complexes were also recorded and briefly commented.

The chemistry and biochemistry of vanadium and the biological activities exerted by vanadium compounds.

Abstract: 6.1.2. Aqueous V(III) Chemistry 877 6.1.3. Oxidation State of Vanadium in Tunicates 878 6.1.4. Uptake of Vanadate into Tunicates 879 6.1.5. Vanadium Binding Proteins: Vanabins 879 6.1.6. Model Complexes and Their Chemistry 880 6.1.7. Catechol-Based Model Chemistry 880 6.1.8. Vanadium Sulfate Complexes 881 6.2. Fan Worm Pseudopotamilla occelata 883 7. Vanadium Nitrogenase 883 7.1. Nitrogenases 883 7.2. Biochemistry of Nitrogenase 884 7.3. Clusters in Nitrogenase and Model Systems: Structure and Reactivity 885

The perovskite structure—a review of its role in ceramic science and technology

Abstract: Starting with the history of the fundamental science of the relation of structure to composition delineated completely by Goldschmidt, we use the perovskite structure to illustrate the enormous pow...

CALCIUM OXALATE IN PLANTS: Formation and Function

Abstract: Calcium oxalate (CaOx) crystals are distributed among all taxonomic levels of photosynthetic organisms from small algae to angiosperms and giant gymnosperms. Accumulation of crystals by these organisms can be substantial. Major functions of CaOx crystal formation in plants include high-capacity calcium (Ca) regulation and protection against herbivory. Ultrastructural and developmental analyses have demonstrated that this biomineralization process is not a simple random physical-chemical precipitation of endogenously synthesized oxalic acid and environmentally derived Ca. Instead, crystals are formed in specific shapes and sizes. Genetic regulation of CaOx formation is indicated by constancy of crystal morphology within species, cell specialization, and the remarkable coordination of crystal growth and cell expansion. Using a variety of approaches, researchers have begun to unravel the exquisite control mechanisms exerted by cells specialized for CaOx formation that include the machinery for uptake and accumulation of Ca, oxalic acid biosynthetic pathways, and regulation of crystal growth.

Molecular mechanism mediating proliferation, defferentiation interralationships during progressie development of the osteoblast phenotype

Abstract: I. Introduction A FUNCTIONAL relationship between cell growth and the initiation and progression of events associated with differentiation has been a fundamental question challenging developmental biologists for more than a century. In the case of bone, as observed with other cells and tissue, the relationship of growth and differentiation must be maintained and stringently regulated, both during development and throughout the life of the organism, to support tissue remodeling. For many years, bone was defined anatomically and examined largely in a descriptive manner by ultrastructural analysis and by biochemical and histochemical methods. These studies provided the basis for our understanding of bone tissue organization and orchestration of the progressive recruitment, proliferation, and differentiation of the various cellular components of bone tissue. Now, complemented by an increased knowledge of molecular mechanisms that are associated with and regulate expression of genes encoding phenotypic compone...

Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan

Abstract: Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.