Search results for "Crista"
showing 10 items of 180 documents
Simulación de un proceso industrial de cristalización de Cloruro de Sodio (NaCl) y aplicaciones
2014
RESUMEN: La cristalización a partir de disoluciones es importante industrialmente dada la gran variedad de sustancias que se comercializan cristalizadas. Para mejorar la enseñanza aprendizaje de esta Operación Básica, en este trabajo, realizado como Trabajo Fin de Carrera de Ingeniería Química, se ha implementado un programa de simulación de una cristalización, partiendo de los datos de una cristalización industrial de NaCl. El objetivo ha sido manejar herramientas de cálculo para simular y optimizar esta operación, lo que permite conocer más profundamente el proceso de la cristalización y la utilización de las herramientas de cálculo, es decir, utilizar simultáneamente los conocimientos ad…
Mixed Titanium–Hafnium Chloridometallate Complexes
2007
The addition of either NEt 3 BzCl or [Ph 3 PNPPh 3 ]Cl (1 equiv. chloride per metal) to a 1:1 mixture of HfCl 4 and TiCl 3 in SOCl 2 results in Ti oxidation and leads to the corresponding salts of the [TiHfCl 10 ] 2- ion. A solution IR investigation in the v(M-Cl) region indicates that this ion is in equilibrium with the homodimetallic [Ti 2 Cl 10 ] 2- and [Hf 2 Cl 10 ] 2- ions. An X-ray study of the NEt 3 Bz + salt reveals an edge-sharing bioctahedral dianion sitting on a crystallographic inversion centre. The crystal is a solid solution of different species with compositional disorder at the metal site, each metal position having the occupancy Ti 0.685 Hf 0.315 . The M-M and M-Cl distance…
High oxidation state aqueous organometallics: synthesis and structure of a dinuclear oxo(pentamethylcyclopentadienyl)acetato complex of molybdenum(IV…
2003
International audience; The zinc reduction of Cp*2Mo2O5 in a MeOH–H2O mixture in the presence of acetic acid affords the diamagnetic dinuclear compound [Cp*MoO(O2CCH3)]2. An X-ray structural investigation reveals a novel dioxo- and diacetato-bridged structure, with a relatively strong metal–metal bond [2.5524(3) Å]. The compound exhibits a reversible one-electron oxidation process in the cyclic voltammogram. A comparison with other related structures reveals the effect of the electric charge on the mononuclear or dinuclear structural choice.Zinc reduction of Cp*2Mo2O5 in water–methanol in the presence of acetic acid affords compound Cp*2Mo2O2(O2CCH3)2, whose dinuclar tetrabridged structure …
In and out: crystal engineering for reversible iodine uptake
2020
In this issue of Acta Crystallographica Section B, Moghzi et al. (2020) report the chemical design of a metal-organic compound with an outstanding iodine (I2) sorption capability. Sequestration of I2, an extremely volatile gas, has important applications in terms of controlling radioactive gases, as various radionuclides of I2 are released during the fission of nuclear fuels. Thus, the preparation of porous materials that can efficiently capture and store I2 is of importance not only from an academic point of view, but also for real-life applications.
Syntheses, characterisation, magnetism and photoluminescence of a homodinuclear Ln(III)-Schiff base family.
2009
A novel family of homodinuclear complexes of the general formula [Ln(2)L(2)(X)(2)] (where Ln = Nd(3+), Pr(3+), Sm(3+) and Tb(3+) for 1, 2, 3 and 4, respectively and X, the coordinated NO(3)(-) or Cl(-) anion) has been synthesised from the corresponding lanthanide(III) salts with the pentadentate dianionic Schiff base ligand, H(2)L [N(1),N(3)-bis(salicylideneimino)diethylenetriamine], that exhibits a N(3)O(2) donor set. Single crystal X-ray diffraction studies evidenced the isostructurality of this family of centrosymmetric neutral dinuclear entities where the Ln(III) metal centres are coupled together by two phenolato oxygen atoms belonging to two units of ligand (H(2)L). Interestingly, the…
The influence of storage method on the transparency of pig crystalline lens
2019
Este artículo se ha publicado de forma definitiva en: http://www.scielo.br/pdf/abo/v82n1/0004-2749-abo-82-01-0056.pdf Purpose: The porcine eye is frequently used as a research model. This paper analyzes the effect of different storage methods on the transparency of pig crystalline lens. Methods: A spectral transmission curve (from 220 to 780 nm) for the crystalline lens was determined experimentally after storage in different conditions: saline solution, formalin, castor oil, and freezing at -80°C. The total transmission in the visible spectrum, which was used as an index of transparency, was calculated from these curves. For comparative purposes, fresh lenses were evaluated and used as con…
Magnesium recovery from exhausted brine
2016
abstractita
Azide, water and adipate as bridging ligands for Cu(II): Synthesis, structure and magnetism of (μ4-adipato-κ-O)(μ-aqua)(μ-azido-κN1,N1)copper(II) mon…
2016
The Distinguished Scientist Fellowship Program (DSFP) at King Saud University is gratefully acknowledged. The authors are grateful to the Algerian MESRS (Ministère de l’Enseignement Supérieur et de la Recherche Scientifique), the Université Ferhat Abbas Sétif 1, the KSU DSFP program and the Spanish MINECO (CTQ2014-52758-P and MAT2014-56143-R) and the Generalitat Valenciana (PrometeoII/2014/076) for financial support. The synthesis, characterization, single crystal structure and magnetic properties of the compound [(CuN3(OH2))2(adp)]n (1) are presented, in which adp stands for the adipate(2-) anion. This compound consists of layers containing chains of six-coordinated Cu(II) ions; the chains…
Slow Relaxation of the Magnetization on Frustrated Triangular FeIII Units with S= 1/2 Ground State: The Effect of the Highly Ordered Crystal Lattice …
2021
In order to understand how the different arrangements of highly ordered triangular FeIII S = 1/2 systems with various types of diamagnetic and paramagnetic anions affect their static and dynamic magnetic properties, we have obtained by solvothermal synthesis four new μ3-oxido trinuclear FeIII compounds, [Fe3O(Ac)6(AcNH2)3][BF4]·(CH3CONH2)0.5(H2O)0.5 (1-BF4), [Fe3O(Ac)6(AcNH2)3][GaCl4] (1-GaCl4), [Fe3O(Ac)6(AcNH2)3][FeCl4] (1-FeCl4) and [Fe3O(Ac)6(AcNH2)3][FeBr4] (1-FeBr4), where, Ac- = CH3COO- and AcNH2 = CH3CONH2. The organization of the triangular units is very varied, from segregated stacks to eclipsed equilateral triangular [Fe3O]+ units along the c-axis with intercalated [MX4]- units. …
Refractive lens exchange with a multifocal diffractive aspheric intraocular lens
2012
PURPOSE: To evaluate the safety, efficacy and predictability after refractive lens exchange with multifocal diffractive aspheric intraocular lens implantation. METHODS: Sixty eyes of 30 patients underwent bilateral implantation with AcrySof® ReSTOR® SN6AD3 intraocular lens with +4.00 D near addition. Patients were divided into myopic and hyperopic groups. Monocular best corrected visual acuity at distance and near and monocular uncorrected visual acuity at distance and near were measured before and 6 months postoperatively. RESULTS: After surgery, uncorrected visual acuity was 0.08 ± 0.15 and 0.11 ± 0.14 logMAR for the myopic and hyperopic groups, respectively (50% and 46.67% of patients ha…