Síntesis y reactividad de compuestos ciclometalados derivados de ligandos polidentados

[Resumen] La Tesis Doctoral consiste en un estudio de la síntesis, caracterización estructural y reactividad de nuevos complejos ciclometalados de Pd(II) y Pt(II) derivados de ligandos imínicos y tiosemicarbazona. Los ligandos imina con sustituyentes que contienen grupos tiofeno o alcohol, reaccionan con Pd(OAc)2 para dar complejos ciclometalados diméricos con grupos acetato puente y con el ligando metalado actuando como bidentado del tipo [C,N]. Además, el derivado que contiene el grupo OH se presenta como una mezcla de los isómeros sin y anti de la que se ha conseguido cristalizar selectivamente el isómero sin. Otros lignados base de Schiff con sustituyetnes sobre el nitrógeno imínico de tamaño creciente, se han empleado para mostrar que uno los factores que influyen en la proporción sin/anti es la repulsión estérica. También se describe la reactividad de estos complejos ciclometalados diméricos con ligandos mono, di y trifosfina terciarios que resulta ser la habitual para este tipo de especies. Por otro lado, la reacción del ligando base de Schiff [2-ClC6H4C(H)=NCH2CH2SMe] con acetato de paladio (II) conduce a la obtención de un complejo monomérico en el cual el ligando actúa como tridentado[C,N,S]. El enlace Pd-S se puede romper por tratamiento con mono, di y trifosfinas terciarios y se puede regenerar por reacción con sales de plata (I). Los ligandos tiosemicarbazona muestran un comportamiento diferente frete a la reacción de ciclometalación. Así, reacciona con K2[MCl4] (M=Pd, Pt) para dar oligómeros con cuatro unidades ML (metal ligando) enlazadas a través de puentes azufre y en las cuales el ligando actúa como tridentado [C,N,S]. El enlace puente se rompe fácilmente por reacción con nucleófilos como mono y difosfinas pero el enlace Pd-S de cada una de las unidades ML permanece intacto

Student-Generated Videos to Promote Understanding of Chemical Reactions

Published as part of the Journal of Chemical Education virtual special issue “Teaching Changes and Insights Gained in the Time after COVID-19”.[Abstract] Students were tasked with the creation of videos of ordinary reactions to promote significant learning of complex concepts underlying chemical transformations. Interactive infographics were used to deliver instructions. Afterward, students planned the experimental setup for the reaction execution and video recording using their mobile phones. The videos and an online questionnaire, also created by the students, were shared with other class members using the visual platform Padlet. The reasoning required to elaborate the questions contributed to a better understanding of the principles underpinning the chemical equation. An exit survey showed that planning and performing the activity were not time-consuming for the students. Marks attained by the students in questions related to chemical reactions improved after completing the activity

Evaluation of the in vitro and in vivo efficacy of ruthenium polypyridyl compounds against breast cancer

[Abstract] The clinical success of cisplatin, carboplatin, and oxaliplatin has sparked the interest of medicinal inorganic chemistry to synthesize and study compounds with non-platinum metal centers. Despite Ru(II)–polypyridyl complexes being widely studied and well established for their antitumor properties, there are not enough in vivo studies to establish the potentiality of this type of compound. Therefore, we report to the best of our knowledge the first in vivo study of Ru(II)–polypyridyl complexes against breast cancer with promising results. In order to conduct our study, we used MCF7 zebrafish xenografts and ruthenium complexes [Ru(bipy)2(C12H8N6-N,N)][CF3SO3]2Ru1 and [{Ru(bipy)2}2(μ-C12H8N6-N,N)][CF3SO3]4Ru2, which were recently developed by our group. Ru1 and Ru2 reduced the tumor size by an average of 30% without causing significant signs of lethality when administered at low doses of 1.25 mg·L−1. Moreover, the in vitro selectivity results were confirmed in vivo against MCF7 breast cancer cells. Surprisingly, this work suggests that both the mono- and the dinuclear Ru(II)–polypyridyl compounds have in vivo potential against breast cancer, since there were no significant differences between both treatments, highlighting Ru1 and Ru2 as promising chemotherapy agents in breast cancer therapy.Xunta de Galicia; ED431C 2018/39Portugal. Fundação para a Ciência e a Tecnologia; PEst 2015-2020Portugal. Fundação para a Ciência e a Tecnologia; UID/Multi/04349/2013Portugal. Fundação para a Ciência e a Tecnologia; RECI/QEQ-QIN/0189/2012Portugal. Fundação para a Ciência e a Tecnologia; UID/QUI/00100/2020Portugal. Fundação para a Ciência e a Tecnologia; UIDP/04378/2020Portugal. Fundação para a Ciência e a Tecnologia; UIDB/04378/2020Portugal. Fundação para a Ciência e a Tecnologia; LA/P/0140/202

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

Alternativa de juegos físico-deportivo-recreativos para el empleo del tiempo libre de los jóvenes en la comunidad.

En el presente artículo se aborda sobre la estructuración de una alternativa de juegos físico-deportivo-recreativos, sustentada en los criterios de gustos y preferencias para lograr el adecuado empleo del tiempo libre de los jóvenes en la comunidad “Punta Brava” del municipio Jiguaní. La misma aporta una congregación de actividades por áreas de trabajo, donde se incluyen adecuaciones de las diferentes disciplinas recreativas con el objetivo de estimular el interés y la motivación de este grupo etário

Valores del antígeno prostático específico en adultos de 50 a 59 años de las parroquias urbanas de la ciudad de Cuenca. 2013

El Antígeno Prostático Específico (PSA) es una glicoproteína secretada por las células epiteliales de la próstata cumple una función importante en la licuefacción del esperma y en la movilidad de los espermatozoides, el PSA total se mantiene en niveles inferiores a 4ng/ml, niveles superiores se detectan en prostatitis, hiperplasia prostática benigna, cáncer de próstata, por ende es necesario un control periódico del PSA total. Este estudio es observacional de tipo descriptivo cuyo objetivo es determinar los valores del PSA mediante la técnica de micro ELISA en adultos de 50 a 59 años y relacionar la positividad de la prueba con los factores de riesgo: edad, antecedentes hereditarios, adicciones tóxicas, factores socioeconómicos, infección e inflamación del aparato urinario, actividad sexual y enfermedades venéreas, en una muestras de 279 pacientes que pertenecen a las 15 parroquias urbanas de la ciudad de Cuenca. El procesamiento de las muestras fue realizado en el Laboratorio del Centro de Diagnóstico y de Investigaciones Biomédicas de la Facultad de Ciencias Médicas de la Universidad de Cuencacumpliendo con las normas de bioseguridad y control de calidad. Se encontró los siguientes resultados: el 4% de los pacientes estudiados tienen valores superiores a 3.99ng/ml. El porcentaje mayor (10%) de casos positivos se encuentra en la edad de 58 a 59 años. Al comparar los casos positivos con las variables en estudio se encuentra una significación estadística (p < 0.05) en las siguientes: antecedentes familiares de enfermedad prostática, actividad física, consumo de cigarrillo, alcohol y última inflamación del aparato urinario. PALABRAS CLAVE: ANTIGENO PROSTATICO ESPECIFICO/ANALISIS; MEDIADA EDAD; ELISA/METODO; NEOPLASIAS DE LA PROSTATA/EPIDEMIOLOGIA; HIPERPLASIA PROSTATICA/EPIDEMIOLOGIA; PROSTATITIS/EPIDEMIOLOGIA; ZONAS URBANAS; CUENCA-ECUADOR.Prostate Specific Antigen (SPA) is a glycoprotein secreted by the prostate epithelial cells that plays an important role in liquefaction of semen and the sperm motility. The total PSA remains at levels below 4ng/ml, higher levels are detected in prostatitis, benign prostatic hyperplasia, prostate cancer, so it is necessary to regularly monitor the total PSA. This study is observational and descriptive whose objective is to determine the values of PSA by micro ELISA technique in adults aged 50-59 years and then relate the test positivity with risk factors:age, heredity, toxic addictions, socio-economic factors, infection and inflammation of the urinary tract, sexual activity and venereal disease in a sample of 279 patients belonging to 15 urban parishes of Cuenca city. The processing of the samples was performed at the Laboratory Diagnostic Center and Biomedical Research of the Faculty of Medicine at the University of Cuenca, in compliance with biosafety standards and quality control. We found the following results: 4% of the patients had values above 3.99ng/ml. The largest percentage (10%) of positive cases is in the age of 58-59 years. When comparing the positive cases the study variables is statistical significance (p≤ 0.05) in the following: a family history of prostate disease, physical activity, cigarette smoking, alcohol and inflammation of the urinary tract. KEYWORDS: PROSTATE SPECIFIC ANTIGEN ANALYSIS: MIDDLE-AGED/AGED; ENZYME–LINKED INMUNOSORBENT ASSAY METHOD; PROSTATIC NEOPLASMS EPIDEMIOLOGY; PROSTATIC HYPERPLASIA EPIDEMIOLOGY, PROSTATITIS EPIDEMIOLOGY; URBAN ZONES; CUENCA-ECUADOR.Licenciada y Licenciado en Laboratorio ClínicoCuenc

Trapping of pyrid-2-ylidenes by [Ru3(CO)12]: Orthometalated pyrid-2-ylidenes in triruthenium clusters

8 páginas, 6 figuras, 6 tablas, 5 esquemas.Six-membered-ring N-heterocyclic carbenes having only one N atom (NHC1N-R6 carbenes) can be easily prepared by simple deprotonation of readily available N-methylpyridinium-type cations with K[N(SiMe3)2]. They have been trapped in solution with [Ru3(CO)12] to give novel triruthenium clusters that contain orthometalated NHC1N-R6 carbene ligands in a face-capping coordination mode. Four NHC1N-R6-derived compounds of general formula [Ru3(μ-H)(μ3-κ2C2,C3-L)(CO)9] (L = N-methylpyrid-3-yl-2-ylidene (1; from N-methylpyridinium), N-methyl-6-picolin-3-yl-2-ylidene (2; from N-methyl-2-picolinium), N-methyl-4-picolin-3-yl-2-ylidene (3; from N-methyl-4-picolinium), and N-methylquinolin-3-yl-2-ylidene (4; from N-methylquinolinium)) have been isolated and characterized. The mechanism of the reaction that leads to compound 1 from N-methylpyrid-2-ylidene and [Ru3(CO)12], as a case study, has been modeled using DFT calculations. The high basicity of the NHC1N-R6 carbenes, the close proximity of a carbene ligand ortho-C−H bond to a cluster metal atom, and the irreversibility of the CO elimination steps trigger the orthometalation of the NHC1N-R6 carbenes and the subsequent face-capping coordination of the metalated ligands. The N-methyl-4-picolinium salts of two polynuclear carbonyl dianions, the previously known [Ru6(μ3-CO)2(μ-CO)2(CO)14]2− (52−) and the novel [Ru5(μ4-O)(μ-CO)2(μ3-CO)2(CO)10]2− (62−), have also been isolated from [Ru3(CO)12] and N-methyl-4-picolin-2-ylidene in the presence of adventitious moisture. The pentanuclear dianion 62− contains a μ4-oxo ligand in a hitherto unknown square face-capping coordination mode.This work has been supported by the European Union (FEDER grants), the Spanish MICINN (projects CTQ2007-60865 and MAT2006-1997), and the Government of Principado de Asturias (project IB09-093). Fellowships from the Venezuelan University of Carabobo (to M.G.S.-V.) and Xunta de Galicia (to D. V.-G.) are also acknowledged.Peer reviewe

From allenes to edge-bridging allyl ligands or face-capping alkenyl ligands on a triruthenium hydrido carbonyl cluster: An experimental and DFT computational study

11 páginas, 11 figuras, 6 esquemas, 5 tablas.Terminal allenes, H2CCCR1R2 (R1 = R2 = Me; R1 = SiMe3, R2 = Me; R1 = CO2Et, R2 = H; R1 = Cy, R2 = H), react with the hydrazido-capped hydrido carbonyl triruthenium complex [Ru3(μ-H)(μ3-κ2-HNNMe2)(CO)9] (1) in THF at reflux temperature to give the allyl-bridged derivatives [Ru3(μ-κ3-H2CCHCR1R2)(μ3-κ2-HNNMe2)(μ-CO)2(CO)6], as mixtures of syn-allyl and anti-allyl isomers when R1 ≠ R2. These reactions also produce a small amount of an alkenyl-capped derivative, [Ru3(μ3-κ2-HNNMe2)(μ3-κ2-MeCCHR1)(μ-CO)2(CO)6], when monosubstituted allenes (R2 = H) are used. Density functional theory calculations have shown that the reactions that give edge-bridging allyl or face-capping alkenyl derivatives from compound 1 and allene are multistep processes. In both cases, the first step, a bimolecular allene for CO substitution, is rate-limiting. The way the allene approaches the cluster complex determines the formation of an allyl or alkenyl product, since this fact decides the final destiny of the hydride ligand, which can be transferred to the central C atom of the allene to give an allyl product or to the terminal CH2 fragment of the allene to give an alkenyl product.This work has been supported by the European Union (FEDER grants) and the Spanish MICINN (projects CTQ2007-60865 and MAT2006- 1997). We also thank Xunta de Galicia for a fellowship to D.V.-G.Peer reviewe

Reactivity of [Os3(μ-H)2(CO)10] with N-Heterocyclic carbenes: A combined experimental and DFT computational study

9 páginas, 6 figuras, 1 esquema, 3 tablas.The unsaturated triosmium dihydrido cluster [Os3(μ-H)2(CO)10] (1) reacts at room temperature with N-heterocyclic carbenes (NHCs) of the 1,3-disubstituted imidazol-2-ylidene type (R1R2Im). While the addition product [Os3H(μ-H)(NHC)(CO)10] has been obtained only for NHC = Mes2Im, CO-substitution derivatives of the type [Os3(μ-H)2(NHC)(CO)9] have been obtained for NHC = Me2Im, MePhIm, Ph2Im, and Mes2Im. Small amounts of the hydroxo-bridged derivatives [Os3(μ-H)(μ-OH)(NHC)(CO)9] (NHC = Me2Im, MePhIm) are also formed in wet solvents. DFT mechanistic studies on the reactions of compound 1 with the small Me2Im and the very bulky Mes2Im have revealed that the substitution reactions follow an associative reaction pathway that starts with the addition of the NHC to compound 1 (in one elementary step that gives [Os3H(μ-H)(NHC)(CO)10]) and ends with the elimination of a CO ligand (in three steps from [Os3H(μ-H)(NHC)(CO)10]) to give the final substitution product [Os3(μ-H)(μ-OH)(NHC)(CO)9]. The relative energy of each stationary point depends upon the NHC ligand used, those of the Mes2Im system being higher than those of the Me2Im system. This computational study has also explained why the addition intermediate [Os3H(μ-H)(NHC)(CO)10] has been isolated only for NHC = Mes2Im.This work has been supported by the European Union (FEDER grants), the Spanish MICINN (projects CTQ2007-60865 and MAT2006-1997), and the Government of Principado de Asturias (project IB09-093). Fellowships toM.G.S.-V. (from the University of Carabobo, Venezuela) and D.V.-G. (from Xunta de Galicia, Spain) are also acknowledged.Peer reviewe