Química dos metais de transición e os seus compostos de coordinación

Titulación: Grao en Enxeñaría de Procesos Químicos Industriais -- Materia: Química InorgánicaA presente unidade didáctica abarca o Bloque VIII da materia Química Inorgánica, centrado na Química dos metais de transición e os seus compostos de coordinación. Este tema abórdase ao final do programa da materia, despois de facer un percorrido por algúns conceptos xerais da Química Inorgánica, pola Química dos elementos non metálicos e dos metais dos grupos principais. Nesta unidade didáctica faise un estudo da Química dos metais de transición máis relevantes a nivel industrial e biolóxico, centrándose na súa obtención, na reactividade, nas súas principais aplicacións e na súa Química de coordinación. Esta unidade didáctica, no que se refire a tódalas actividades nela propostas, está deseñada para ser desenvolvida ao longo de 14 horas. Preténdese que o alumnado, dado que a Titulación é o Grao en Enxeñaría de Procesos Químicos Industriais, adquira un coñecemento sistematizado por grupos dos elementos metálicos de transición e os seus compostos de coordinación máis importantes, mediante o exame dos seguintes aspectos: obtención, estrutura, propiedades físicas e químicas e reactividade. Tamén se pretende a adquisición de destreza para a aplicación práctica dos coñecementos acadados a casos reais, ademais de relacionar estes coñecementos directamente cos procesos industriais máis importantes.Universidade de Santiago de Compostela. Servizo de Normalización Lingüístic

Synthesis and X-ray Crystal Structure of the Thiosemicarbazone L bis(4-N-Methyl-Thiosemicarbazone)-4,4'-Diacetylphenylmethane

The 18th International Electronic Conference on Synthetic Organic Chemistry session Polymer and Supramolecular ChemistryWe report herein the synthesis of the tetradentate thiosemicarbazone ligand bis(4-N-methyl-thiosemicarbazone)-4,4'-diacetylphenylmethane, which is a suitable precursor in supramolecular chemistry for the preparation of helical metal complexes. This molecule has been characterized by microanalysis, mass spectrometry, IR and 1H and 13C NMR spectroscopies. Its crystal structure has also been analyse

Study of the conformational rearrangement of a tetradentate hydrazone ligand

We report herein the first example of a tetradentate hydrazone structurally studied. The analysis of the conformations of this molecule together with the hydrogen bonding interactions allowed us to investigate the changes experienced by this ligand upon coordination to metal center

Neuroprotective effects of fluorophore-labelled manganese complexes: determination of ROS production, mitochondrial membrane potential and confocal fluorescence microscopy studies in neuroblastoma cells

In this work, four manganese(II) complexes derived from the ligands H2L1-H2L4, that incorporate dansyl or tosyl fluorescent dyes, have been investigated in term of their antioxidant properties. Two of the manganese(II) complexes have been newly prepared using the asymmetric half-salen ligand H2L2 and the thiosemicarbazone ligand H2L3. The four organic strands and the manganese complexes have been characterized by different analytical and spectroscopic techniques. The study of the antioxidant behaviour of these two new complexes and other two fluorophore-labelled analogues was tested in SH-SY5Y neuroblastoma cells. These four model complexes 1–4 were found to protect cells from oxidative damage in this human neuronal model, by reducing the release of reactive oxygen species. Complexes 1–4 significantly improved cell survival, with levels between 79.1 ± 0.8% and 130.9 ± 4.1%. Moreover, complexes 3 and 4 were able to restore the mitochondrial membrane potential at 1 μM, with 4 reaching levels higher than 85%, similar to the percentages obtained by the positive control agent cyclosporin A. The incorporation of the fluorescent label in the complexes allowed the study of their ability to enter the human neuroblastoma cells by confocal microscopyThe research leading to these results has received funding from the following FEDER cofunded-grants. From Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia, 2017 GRC GI-1682 (ED431C 2017/01), 2018 GRC GI-1584 (ED431C 2018/13), MetalBIO Network (ED431D 2017/01). From CDTI and Technological Funds, supported by Ministerio de Economía, Industria y Competitividad IISCIII/PI19/001248. From Ministerio de Ciencia, Innovación y Universidades, MULTIMETDRUGS (RED2018-102471-T). From European Union, Interreg AlertoxNet EAPA-317-2016, Interreg Agritox EAPA-998-2018, and H2020 778069-EMERTOXS

Synthetic Route to Novel Asymmetric Tetradentate Ligands Containing Both Amino and Imino Groups

The 18th International Electronic Conference on Synthetic Organic Chemistry session General Organic SynthesisThe synthesis of a new asymmetric ligand (E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(methyl)amino)ethyl)imino)methyl)phenol, which was conceived to model the asymmetry in the active site of peroxidase/catalase mimics, is reported. The new synthetic route involves seven steps: 1) obtention of phthalimido-acetal; 2) Acetal deprotection; 3) Synthesis of the salicylamine; 4) Obtention of the benzoxacine; 5) Reduction of the benzoxacine with NaBH3CN; 6) Reduction with hydrazine to form salycilamine; 7) Synthesis of the final ligand by condensation of salicylamine with salycilaldehyde. All organic products were characterised by microanalysis and 1H NMR, IR and mass spectroscopie

Exploring the Biological Properties of Zn(II) Bis thiosemicarbazone Helicates

The design of artificial helicoidal molecules derived from metal ions with biological properties is one of the objectives within metallosupramolecular chemistry. Herein, we report three zinc helicates derived from a family of bis thiosemicarbazone ligands with different terminal groups, Zn(L Me)∙2HO 1, Zn(L Ph)∙2HO 2 and Zn(L PhNO2) 3, obtained by an electrochemical methodology. These helicates have been fully characterized by different techniques, including X-ray diffraction. Biological studies of the zinc(II) helicates such as toxicity assays with erythrocytes and interaction studies with proteins and oligonucleotides were performed, demonstrating in all cases low toxicity and an absence of covalent interaction with the proteins and oligonucleotides. The in vitro cytotoxicity of the helicates was tested against MCF-7 (human breast carcinoma), A2780 (human ovarian carcinoma cells), NCI-H460 (human lung carcinoma cells) and MRC-5 (normal human lung fibroblasts), comparing the IC values with cisplatin. We will try to demonstrate if the terminal substituent of the ligand precursor exerts any effect in toxicity or in the antitumor activity of the zinc helicates

Pursuing the Elixir of Life: In Vivo Antioxidative Effects of Manganosalen Complexes

Manganosalen complexes are coordination compounds that possess a chelating salen-type ligand, a class of bis-Schiff bases obtained by condensation of salicylaldehyde and a diamine. They may act as catalytic antioxidants mimicking both the structure and the reactivity of the native antioxidant enzymes active site. Thus, manganosalen complexes have been shown to exhibit superoxide dismutase, catalase, and glutathione peroxidase activities, and they could potentially facilitate the scavenging of excess reactive oxygen species (ROS), thereby restoring the redox balance in damaged cells and organs. Initial catalytic studies compared the potency of these compounds as antioxidants in terms of rate constants of the chemical reactivity against ROS, giving catalytic values approaching and even exceeding that of the native antioxidative enzymes. Although most of these catalytic studies lack of biological relevance, subsequent in vitro studies have confirmed the efficiency of many manganosalen complexes in oxidative stress models. These synthetic catalytic scavengers, cheaper than natural antioxidants, have accordingly attracted intensive attention for the therapy of ROS-mediated injuries. The aim of this review is to focus on in vivo studies performed on manganosalen complexes and their activity on the treatment of several pathological disorders associated with oxidative damage. These disorders, ranging from the prevention of fetal malformations to the extension of lifespan, include neurodegenerative, inflammatory, and cardiovascular diseases; tissue injury; and other damages related to the liver, kidney, or lungs

Designing a Phosphino-Thiosemicarbazone Ligand Capable of Stabilizing Coinage Metal Ions

Thiosemicarbazones are interesting organic skeletons due to their great coordinative versatility and their interesting biological and pharmacological properties, as well as their structural diversity. However, the isolation of their monovalent coinage metal complexes, such as Cu(I), Ag(I) and Au(I), is a partially studied field, since co-ligands with soft donor atoms such as phosphines are required. In this context, our research group has been studying a new family of ligands capable of stabilizing coinage complexes without the need for auxiliary co-ligands. To this end, it was decided to incorporate a phosphorus atom into the structure of a thiosemicarbazone kernel. This work presents the design, synthesis and structural characterization of a new phosphino-thiosemicarbazone ligand

Methanolysis of 2-Cyanopyridine in the Coordination Sphere of Manganese(II). The Structure of Mn4L6Cl2 cluster (L = Methyl Picolinimidate)

The reaction of 2-cyanopyridine and Mn(II) in methanol solution led to the formation of a Mn4L6Cl2 cluster 1 containing O-methyl picolimidate as a ligand (L). The coordination of 2-cyanopyridine to the Mn(II) ion as a chelating bidentate ligand activated the CN triple bond which subsequently suffered a nucleophilic attack by CH3OH. Complex 1 was characterized by standard techniques including microanalysis, IR spectroscopy, ESI spectrometry, and magnetic susceptibility measurements. The crystal structure of 1 was determined by X-ray diffraction techniques, and the crystallographic studies revealed a planar-diamond array for 1 where the six monoanionic picolinimidates act as chelating ligands through the two nitrogen atoms