Arte urbano, ¿patrimonio cultural etnográfico de nosotros mismos?

[ES] En este texto se reflexiona sobre la dificultad que entraña comprender como patrimonio cultural el arte urbano, un fenómeno heterogéneo, cambiante y en proceso de construcción, demasiado cercano en el tiempo para contar con la suficiente perspectiva, pero que es un fiel reflejo de la sociedad de nuestra época. A pesar de que existen diversos ejemplos de reconocimiento patrimonial de obras concretas de características muy diferentes sigue siendo difícil enmarcar este tipo de producciones bajo alguno de los epígrafes existentes en la definición general de Patrimonio Cultural.Sánchez Pons, M. (2021). Arte urbano, ¿patrimonio cultural etnográfico de nosotros mismos?. Revista PH (Online). (103):187-189. https://doi.org/10.33349/2021.103.492618718910

Solvent dependent formation of Cu (II) complexes based on isonicotinamide ligand

Five solvent-dependent Cu(II) compounds have been synthesized with [Cu(μ-OAc)(μ-Pip)(MeOH)]2 (OAc = acetate; Pip = 1,3-benzodioxolecarboxylate) and isonicotinamide (Isn) as an auxiliary ligand in different solvents. In all the compounds, Pip units are displaced resulting in dimeric [Cu(μ-OAc)(OAc)(Isn)2(solvent)]2 (solvent = MeOH (2a), dmf and H2O (3) or H2O and HPip (4a)), paddle-wheel [Cu(μ-OAc)2(Isn)]2·2dmso (5) or monomeric compounds [Cu(OAc)2(HOAc)(Isn)2]·HOAc (6). All of them have been characterized by analytical and ATR-FTIR techniques and their X-ray crystal structures solved. The OAc anions construct different arrays and exhibit different coordination modes depending on the solvent used. The supramolecular expansion is constantly determined by the amide-amide pattern and the role of the occluded solvent molecules. This tendency is confirmed by Hirshfeld Surface analysis. Finally, the thermal stability of compound 4a has been analyzed

The Formation of a Unique 2D Isonicotinate Polymer Driven by Cu(II) Aerobic Oxidation

The isolation and structural characterization of a unique Cu(II) isonicotinate (ina) material with 4-acetylpyridine (4-acpy) is provided. The formation of [Cu(ina)(2)(4-acpy)](n) (1) is triggered by the Cu(II) aerobic oxidation of 4-acpy using O-2. This gradual formation of ina led to its restrained incorporation and hindered the full displacement of 4-acpy. As a result, 1 is the first example of a 2D layer assembled by an ina ligand capped by a monodentate pyridine ligand. The Cu(II)-mediated aerobic oxidation with O-2 was previously demonstrated for aryl methyl ketones, but we extend the applicability of this methodology to heteroaromatic rings, which has not been tested so far. The formation of ina has been identified by H-1 NMR, thus demonstrating the feasible but strained formation of ina from 4-acpy in the mild conditions from which 1 was obtained

Isonicotinamide-Based Compounds: From Cocrystal to Polymer

The reaction between [Cu(μ-OAc)(μ-Pip)(MeOH)]2 (1) (OAc = acetate; Pip = 1,3-benzodioxole-5-carboxylate) and isonicotinamide (Isn) in MeOH as solvent yielded two mixture pairs of three compounds: {(HPip)2(Isn) (2), [Cu(Pip)2(Isn)2] (3)} and {(3), {[Cu3(Pip)2(OAc)2(μ-Isn)2(Isn)2(μ-OCH3)2(MeOH)2]·2MeOH}n (4)}. Modifying the reaction conditions (t, T, molar ratio), 2 and 3 have been successfully isolated, whereas 3 and 4 had to be mechanically separated. The recrystallization of 3 in pentanol yielded single crystals of compound [Cu(Pip)2(Isn)2]·C5H11OH (3a). The X-ray crystal structure of 2, 3a, and 4 has been elucidated showing a cocrystal, a monomer, and an unusual coordination polymer, respectively. The Pip ligand exhibited a chelate (3a) or a monodentate (4) coordination mode, but the Isonicotinamide (Isn) ligand is the one that promoted the arrangement of different structures and also mainly directs the formation of the 2D and 3D supramolecular assemblies. All the structures have been analyzed by Hirshfeld surface. In addition, the energy frameworks and lattice energy values of 2 and 3a have been calculated

Zn(II) and Cd(II) monomer, dimer and polymer compounds coordinated by benzoic acid and 4-acetylpyridine: Synthesis and crystal structures

Reaction of MO (MO = Metal oxide, M = Zn(II) or Cd(II)) with benzoic acid (HBz) in H2O/MeOH mixture as solvent yields two benzoate compounds: [Zn(µ-Bz)2]n (1) and [Cd(Bz)2(H2O)3] (2). In addition, the reaction between M(MeCO2)2 (M = Zn(II) or Cd(II)) with HBz and 4-acetylpyridine (4-Acpy) in a 1:2:4 M ratio and in MeOH solution, leads to the formation of [Zn(µ-Bz)2(4-Acpy)]2 (3) and [Cd(µ-Bz)2(4-Acpy)2]2 (4). These four compounds have been fully characterized by analytical and spectroscopic techniques. Besides, their crystal structures have been elucidated revealing a 1D coordination polymer (1), a monomer (2), a paddle-wheel (3) and a dimer (4). In 1, the Zn(II) ion is four-coordinated in a tetrahedral geometry while in 3 is penta-coordinated in a square-pyramidal geometry. By contrast, compounds 2 and 4 exhibit seven-coordinated Cd(II) ions in a pentagonal-bipyramidal geometry. In these set of compounds, the benzoate ligand presents different coordination modes such as bidentate bridged (µ2-η1:η1) (1 and 3), chelate (µ1-η2) (2) and both bridged and chelate (µ2-η2:η1) (4). Besides, their extended structures have been analyzed. Finally, the UV–Vis and fluorescence spectra of all the compounds have been recorded as well as their quantum yields calculated

Controlling the Formation of Two Concomitant Polymorphs in Hg(II)Coordination Polymers

Controlling the formation of the desired product in the appropriate crystalline form is the fundamental breakthrough of crystal engineering. On that basis, the preferential formation between polymorphic forms, which are referred to as different assemblies achieved by changing the disposition or arrangement of the forming units within the crystalline structure, is one of the most challenging topics still to be understood. Herein, we have observed the formation of two concomitant polymorphs with general formula {[Hg(Pip)2(4,4′-bipy)]·DMF}n (P1A, P1B; Pip = piperonylic acid; 4,4′-bipy = 4,4′-bipyridine). Besides, [Hg(Pip)2(4,4′-bipy)]n (2) has been achieved during the attempts to isolate these polymorphs. The selective synthesis of P1A and P1B has been successfully achieved by changing the synthetic conditions. The formation of each polymorphic form has been ensured by unit cell measurements and decomposition temperature. The elucidation of their crystal structure revealed P1A and P1B as polymorphs, which originates from the Hg(II) cores and intermolecular associations, especially pinpointed by Hg···π and π···π interactions. Density functional theory (DFT) calculations suggest that P1B, which shows Hg(II) geometries that are further from ideality, is more stable than P1A by 13 kJ·mol–1 per [Hg(Pip)2(4,4′-bipy)]·DMF formula unit, and this larger stability of P1B arises mainly from metal···π and π···π interactions between chains. As a result, these structural modifications lead to significant variations of their solid-state photoluminescence

Steric and Electronic Effects on the Structure and Photophysical Properties of Hg(II) Complexes

Since many factors influence the coordination around a metal center, steric and electronic effects of the ligands mainly determine the connectivity and, thus, the final arrangement. This is emphasized on Hg(II) centers, which have a zero point stabilization energy and, thus, a flexible coordination environment. Therefore, the unrestricted Hg(II) geometry facilitates the predominance of the ligands during the structural inception. Herein, we synthesized and characterized a series of six Hg(II) complexes with general formula (Hg(Pip)2(dPy)) (Pip = piperonylate, dPy = 3- phenylpyridine (3-phpy) (1), 4-phenylpyridine (4-phpy) (2), 2,2′- bipyridine (2,2′-bipy) (3), 1,10-phenanthroline (1,10-phen) (4), 2,2′:6′,2′-terpyridine (terpy) (5), or di(2-picolyl)amine (dpa) (6)). The elucidation of their crystal structures revealed the arrangement of three monomers (3, 5, and 6), one dimer (4), and two coordination polymers (1 and 2) depending on the steric requirements of the dPy and predominance of the ligands. Besides, the study of their photophysical properties in solution supported by TD-DFT calculations enabled us to understand their electronic effects and the influence of the structural arrangement on them

A Hg(I) corrugated sheet assembled by auxiliary dioxole groups and Hg··· π interactions

The formation of a new double-stranded staircase Hg(I) supramolecular assembly is reported. It is arranged into 2D corrugated sheets supported by Hg(I)⋯Odioxole and Hg⋯π interactions, resulting from the comproportionation reaction between Hg(II) and Hg(0) species in DMF as a solvent

La evaluación de competencias en los trabajos fin de estudios

En este artículo proponemos un procedimiento objetivo para la evaluación, basada en competencias, de los trabajos fin de grado (TFG) y de máster (TFM) en el contexto de las ingenierías. Dicho procedimiento se ha dividido en seis etapas: (1) definición de las competencias asociadas al TFG o al TFM y de indicadores objetivos; (2) definición de los momentos (hitos) de evaluación, las acciones concretas de evaluación y los agentes implicados; (3) asignación de indicadores objetivos a cada acción de evaluación; (4) definición de los niveles de cumplimiento de cada indicador; (5) elaboración de los informes de evaluación que los agentes evaluadores deberán cumplimentar y (6) definición del criterio de puntación para asignar la nota final a partir de los informes de evaluación. Para cada uno de estos puntos se ofrecen ayudas en forma de encuestas, fichas de competencias y/o ejemplos de aplicación.Peer Reviewe