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1.
J Occup Environ Med ; 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38595081

RESUMEN

OBJECTIVE: This study developed, implemented, and evaluated the feasibility of executing an organizational capacity building intervention to improve bus driver safety and well-being in a Chilean transportation company. METHOD: Through an implementation science lens and using a pre-experimental mixed methods study design, we assessed the feasibility of implementing a participatory organizational intervention designed to build organizational capacity. RESULT: We identified contextual factors that influenced the intervention mechanisms and intervention implementation and describe how the company adapted the approach for unexpected external factors during the COVID-19 pandemic and social and political unrest experienced in Chile. CONCLUSIONS: The intervention enabled the organization to create an agile organizational infrastructure that provided the organization's leadership with new ways to be nimbler and more responsive to workers' safety and well-being needs and was robust in responding to strong external forces that were undermining worker safety and well-being.

2.
bioRxiv ; 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38168163

RESUMEN

BACKGROUND: Hypertension, a disease with known sexual dimorphism, accelerates aging associated arterial stiffening, in part due to the activation of matrix remodeling caused by increased biomechanical load. In this study, we tested the effect of biological sex and the role of the matrix remodeling enzyme lysyl oxidase like 2 (LOXL2) in hypertension induced arterial stiffening. METHODS: Angiotensin II (Ang II) was delivered using osmotic pumps in Loxl2+/- and WT male and female mice. Blood pressure and pulse wave velocity (PWV) were measured noninvasively to assess hypertension and aortic stiffness. Wire myography and uniaxial tensile testing were used to test aortic vasoreactivity and mechanical properties. Aortic wall composition was examined by histology and Western blotting. The effect of biomechanical strain on LOXL2 expression and secretion by vascular smooth muscle (VSMC) and endothelial cells (EC) was evaluated by uniaxial cyclic stretching of cultured cells. The role of LOXL2 catalytic function on VSMC alignment in response to mechanical loading was determined with LOXL2 inhibition and knockout. RESULTS: Ang II infusion induced hypertension in WT and Loxl2+/- mice of both sexes and increased PWV in WT males but not in Loxl2+/- males, WT females, or Loxl2+/- females. LOXL2 depletion protected males from Ang II mediated potentiation of vasoconstriction but worsened in females and improved aortic mechanical properties in both sexes. Histological analysis showed increased aortic wall thickness in hypertensive WT males but not females and increased intralamellar distance in both sexes, that was ameliorated in Loxl2+/- mice. Western blotting revealed increased collagen I, decreased collagen IV, and increased LOXL2 accumulation and processing in hypertensive mice. Hypertensive cyclic strain contributed to LOXL2 upregulation in the cell-derived matrix in VSMCs but not ECs. LOXL2 catalytic function facilitated VSMC alignment in response to biomechanical strain. CONCLUSIONS: In males, arterial stiffening in hypertension is driven both by VSMC response and matrix remodeling. Females exhibit a delayed onset of Ang II-induced hypertension with minimal ECM remodeling but with VSMC dysfunction. LOXL2 depletion ameliorates arterial stiffening and preserves functional contractility and aortic structure in male hypertensive mice. LOXL2 depletion improves aortic mechanics but worsens aortic contractility in hypertensive females. VSMCs are the primary source of LOXL2 in the aorta and hypertension increases LOXL2 processing and shifts to collagen I accumulation. Overall, LOXL2 depletion offers protection in young hypertensive males and females.

3.
Proc Biol Sci ; 290(2005): 20231396, 2023 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-37644835

RESUMEN

Infectious wildlife diseases that circulate at the interface with domestic animals pose significant threats worldwide and require early detection and warning. Although animal tracking technologies are used to discern behavioural changes, they are rarely used to monitor wildlife diseases. Common disease-induced behavioural changes include reduced activity and lethargy ('sickness behaviour'). Here, we investigated whether accelerometer sensors could detect the onset of African swine fever (ASF), a viral infection that induces high mortality in suids for which no vaccine is currently available. Taking advantage of an experiment designed to test an oral ASF vaccine, we equipped 12 wild boars with an accelerometer tag and quantified how ASF affects their activity pattern and behavioural fingerprint, using overall dynamic body acceleration. Wild boars showed a daily reduction in activity of 10-20% from the healthy to the viremia phase. Using change point statistics and comparing healthy individuals living in semi-free and free-ranging conditions, we show how the onset of disease-induced sickness can be detected and how such early detection could work in natural settings. Timely detection of infection in animals is crucial for disease surveillance and control, and accelerometer technology on sentinel animals provides a viable complementary tool to existing disease management approaches.


Asunto(s)
Fiebre Porcina Africana , Sus scrofa , Porcinos , Animales , Fiebre Porcina Africana/diagnóstico , Aceleración , Animales Domésticos , Animales Salvajes , Acelerometría/veterinaria
4.
Acta Pharmaceutica Sinica B ; (6): 3988-4024, 2023.
Artículo en Inglés | WPRIM (Pacífico Occidental) | ID: wpr-1011171

RESUMEN

In recent years, growing awareness of the role of oxidative stress in brain health has prompted antioxidants, especially dietary antioxidants, to receive growing attention as possible treatments strategies for patients with neurodegenerative diseases (NDs). The most widely studied dietary antioxidants include active substances such as vitamins, carotenoids, flavonoids and polyphenols. Dietary antioxidants are found in usually consumed foods such as fresh fruits, vegetables, nuts and oils and are gaining popularity due to recently growing awareness of their potential for preventive and protective agents against NDs, as well as their abundant natural sources, generally non-toxic nature, and ease of long-term consumption. This review article examines the role of oxidative stress in the development of NDs, explores the 'two-sidedness' of the blood-brain barrier (BBB) as a protective barrier to the nervous system and an impeding barrier to the use of antioxidants as drug medicinal products and/or dietary antioxidants supplements for prevention and therapy and reviews the BBB permeability of common dietary antioxidant suplements and their potential efficacy in the prevention and treatment of NDs. Finally, current challenges and future directions for the prevention and treatment of NDs using dietary antioxidants are discussed, and useful information on the prevention and treatment of NDs is provided.

5.
Preprint en Inglés | bioRxiv | ID: ppbiorxiv-471263

RESUMEN

The S:A222V point mutation, within the G clade, was characteristic of the 20E (EU1) SARS-CoV-2 variant identified in Spain in early summer 2020. This mutation has now reappeared in the Delta subvariant AY.4.2, raising questions about its specific effect on viral infection. We report combined serological, functional, structural and computational studies characterizing the impact of this mutation. Our results reveal that S:A222V promotes an increased RBD opening and slightly increases ACE2 binding as compared to the parent S:D614G clade. Finally, S:A222V does not reduce sera neutralization capacity, suggesting it does not affect vaccine effectiveness.

6.
Dalton Trans ; 50(34): 11852-11860, 2021 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-34369506

RESUMEN

Although dendrimer supports have been known as key parts of nanocatalysts, the capability of rigid dendrimers for this function has not yet been reported. Here, the study is focused on ferrocenylmethylenetriazolyl-terminated dendrimers (FcMTPD) as supports of remarkably efficient nanogold and nanopalladium catalysts. A biphasic system is elaborated to evaluate the catalytic activity of FcMTPD-supported Au and Pd nanoparticles (NPs) for the reduction of 4-nitrophenol to 4-aminophenol by NaBH4 at 20 °C, and FcMTPD-supported PdNPs are found to be the best nanocatalysts with a rate constant kapp = 7.8 × 10-2 s-1. Excellent catalytic results are also obtained in this reaction for FcMTPD-supported AuNPs with a rate constant kapp = 5.6 × 10-2 s-1. For both Pd NPs and AuNPs, the kinetic results are shown to strongly depend on the method of preparation of these NPs that influences the NP size and thus their catalytic efficiency. The FcMTPD-stabilized PdNPs are easily recovered and reused at least 13 times, and their catalytic performance displays only a slight decrease during the first seven runs.

7.
ACS Appl Mater Interfaces ; 12(48): 53816-53826, 2020 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-33201661

RESUMEN

Production of hydrogen (H2) upon hydrolysis of inorganic hydrides potentially is a key step in green energy production. We find that visible-light irradiation of aqueous solutions of ammonia-borane (AB) or NaBH4 containing "click"-dendrimer-stabilized alloyed nanocatalysts composed of nanogold and another late transition-metal nanoparticle (LTMNP) highly enhances catalytic activity for H2 generation while also inducing alloy to Au core@M shell nanocatalyst restructuration. In terms of visible-light-induced acceleration of H2 production from both AB and NaBH4, the Au1Ru1 alloy catalysts show the most significant light-boosting effect. Au-Rh and Au-PtNPs are also remarkable with total H2 release time from AB and NaBH4 down to 1.3 min at 25 °C (AuRh), 3 times less than in the dark, and Co is the best earth-abundant metal alloyed with nanogold. This boosting effect is explained by the transfer of plasmon-induced hot electron from the Au atoms to the LTMNP atoms facilitating water O-H oxidative addition on the LTMNP surface, as shown by the large primary kinetic isotope effect kH/kD upon using D2O obtained for both AB and NaBH4. The second simultaneous and progressive effect of visible-light irradiation during these reactions, alloy to Au core@M shell restructuration, enhances the catalytic activity in the recycling, because, in the resulting Au core@M shell, the surface metal (such as Ru) is much more active than the original Au-containing alloy surface in dark reactions. There is no light effect on the rate of hydrogen production for the recycled nanocatalyst because of the absence of Au on the NP surface, but it is still very efficient in hydrogen release during four cycles because of the initial light-induced restructuration, although it is slightly less efficient than the original nanoalloy in the presence of light. The dendritic triazole coordination on each LTMNP surface appears to play a key role in these remarkable light-induced processes.

8.
Preprint en Inglés | bioRxiv | ID: ppbiorxiv-191072

RESUMEN

With the help of novel processing workflows and algorithms, we have obtained a better understanding of the flexibility and conformational dynamics of the SARS-CoV-2 spike in the prefusion state. We have re-analyzed previous cryo-EM data combining 3D clustering approaches with ways to explore a continuous flexibility space based on 3D Principal Component Analysis. These advanced analyses revealed a concerted motion involving the receptor-binding domain (RBD), N-terminal domain (NTD), and subdomain 1 and 2 (SD1 & SD2) around the previously characterized 1-RBD-up state, which have been modeled as elastic deformations. We show that in this dataset there are not well-defined, stable, spike conformations, but virtually a continuum of states moving in a concerted fashion. We obtained an improved resolution ensemble map with minimum bias, from which we model by flexible fitting the extremes of the change along the direction of maximal variance. Moreover, a high-resolution structure of a recently described biochemically stabilized form of the spike is shown to greatly reduce the dynamics observed for the wild-type spike. Our results provide new detailed avenues to potentially restrain the spike dynamics for structure-based drug and vaccine design and at the same time give a warning of the potential image processing classification instability of these complicated datasets, having a direct impact on the interpretability of the results.Competing Interest StatementThe authors have declared no competing interest.View Full Text

9.
Resuscitation ; 122: 87-91, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29183833

RESUMEN

OBJECTIVE: To determine the number of potential deceased organ donors from out-of- hospital cardiac arrest cases (OHCA) attended by public physician-led emergency medical services in Spain, based on data recorded in the nationwide Spanish OHCA Registry (OHSCAR). MATERIAL AND METHODS: We analysed OHSCAR data on deceased OHCA patients in Spain during 13 months (1/10/2013 to 31/10/2014). Variables included age, sex, estimated OHCA time, cardiopulmonary resuscitation (CPR) start time and outcome. Inclusion criteria were: age 16-60 years, witnessed OHCA, no return of spontaneous circulation (ROSC) and time interval <15min between OHCA occurrence and CPR initiation. RESULTS: Of a total 8789 cases, 3290 met the age criteria; of these, CPR was not witnessed in 745 cases. Among the remaining 2545 patients, 141 were included in uncontrolled donation after cardiac death (uDCD) programs, 902 arrived at the hospital with ROSC, 64 arrived with ongoing CPR and 15 cases were lost to follow-up. Of the remaining 1423 without ROSC, CPR initiation time was not recorded in 454 cases and 398 did not meet the time criteria <15min between OHCA and CPR initiation. Finally, 571 met all the criteria and could have been potential donors. There were significant differences in the actual donors percentage from potential donors percentage between provinces with and without donor programs (141/322=43.8% versus 0/390=0%), but there were no differences in ROSC between the two types of provinces (418/1320=31.7% versus 652/1970=33.4%). CONCLUSIONS: Many potential donors are missed in current clinical practice. uDCD programs are few and underused even in a country with high rates of organ transplantation.


Asunto(s)
Muerte Encefálica , Reanimación Cardiopulmonar , Paro Cardíaco Extrahospitalario/mortalidad , Donantes de Tejidos/estadística & datos numéricos , Obtención de Tejidos y Órganos/métodos , Circulación Sanguínea , Servicios Médicos de Urgencia , Femenino , Humanos , Masculino , Estudios Retrospectivos , España/epidemiología , Tiempo de Tratamiento , Obtención de Tejidos y Órganos/estadística & datos numéricos
10.
Mater Sci Eng C Mater Biol Appl ; 80: 677-687, 2017 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-28866215

RESUMEN

The development of antifouling coatings with restricted cell and bacteria adherence is fundamental for many biomedical applications. A strategy for the fabrication of antifouling coatings based on the layer-by-layer assembly and thermal annealing is presented. Polyelectrolyte multilayers (PEMs) assembled from chitosan and hyaluronic acid were thermally annealed in an oven at 37°C for 72h. The effect of annealing on the PEM properties and topography was studied by atomic force microscopy, ζ-potential, circular dichroism and contact angle measurements. Cell adherence on PEMs before and after annealing was evaluated by measuring the cell spreading area and aspect ratio for the A549 epithelial, BHK kidney fibroblast, C2C12 myoblast and MC-3T3-E1 osteoblast cell lines. Chitosan/hyaluronic acid PEMs show a low cell adherence that decreases with the thermal annealing, as observed from the reduction in the average cell spreading area and more rounded cell morphology. The adhesion of S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria strains was quantified by optical microscopy, counting the number of colony-forming units and measuring the light scattering of bacteria suspension after detachment from the PEM surface. A 20% decrease in bacteria adhesion was selectively observed in the S. aureus strain after annealing. The changes in mammalian cell and bacteria adhesion correlate with the changes in topography of the chitosan/hyaluronic PEMs from a rough fibrillar 3D structure to a smoother and planar surface after thermal annealing.


Asunto(s)
Quitosano/química , Animales , Adhesión Bacteriana , Escherichia coli , Ácido Hialurónico , Polielectrolitos , Staphylococcus aureus , Propiedades de Superficie
11.
ChemSusChem ; 9(11): 1304-11, 2016 06 08.
Artículo en Inglés | MEDLINE | ID: mdl-27159151

RESUMEN

The challenging coupling of highly substituted terpene oxides and carbon dioxide into bio-based cyclic organic carbonates catalyzed by Al(aminotriphenolate) complexes is reported. Both acyclic as well as cyclic terpene oxides were used as coupling partners, showing distinct reactivity/selectivity behavior. Whereas cyclic terpene oxides showed excellent chemoselectivity towards the organic carbonate product, acyclic substrates exhibited poorer selectivities owing to concomitant epoxide rearrangement reactions and the formation of undesired oligo/polyether side products. Considering the challenging nature of these coupling reactions, the isolated yields of the targeted bio-carbonates are reasonable and in most cases in the range 50-60 %. The first crystal structures of tri-substituted terpene based cyclic carbonates are reported and their stereoconnectivity suggests that their formation proceeds through a double inversion pathway.


Asunto(s)
Dióxido de Carbono/química , Carbonatos/química , Terpenos/química , Catálisis , Óxido de Etileno/química
12.
Dalton Trans ; 45(8): 3564-76, 2016 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-26804332

RESUMEN

A series of imino- and amino-pyridine ligands based on dihydrobenzofurobenzofuran (BFBF) and methanodibenzodioxocine (DBDOC) backbones have been synthesized. These ligands form exclusively dinuclear complexes with metals such as iron(II) and copper(II). The structures for complexes 15, 16, 18, 19, 20, 21, 23, and 24 were determined by X-ray crystallography. The complexes show large distances for the metal nuclei and different geometries depending on the nature of the metal. An octahedral geometry was observed for the iron(II) complexes, while copper(II) complex 24 showed a distorted trigonal bipyramidal geometry. The iron(II) complexes showed activity as catalysts in the cycloaddition of CO2 to epoxides, obtaining moderate yields of cyclic carbonates.

13.
Age (Dordr) ; 36(2): 801-11, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24243397

RESUMEN

This study investigated the effects of a multicomponent exercise intervention on muscle strength, incidence of falls and functional outcomes in frail elderly patients with dementia after long-term physical restraint, followed by 24 weeks of training cessation. Eighteen frail elderly patients with mild dementia (88.1 ± 5.1 years) performed a multicomponent exercise program, which consisted of 4 weeks of walking, balance and cognitive exercises, followed by 4 weeks of resistance exercise performed twice weekly [8-12 repetitions at 20-50 % of the one-repetition maximum (1RM)], combined with walking, balance and cognitive exercises. Before and after training, as well as after 24 weeks of training cessation, strength outcomes, Barthel Index, balance, gait ability, rise from a chair ability, dual task performance, incidence of falls and Mini-Mental State Examination were assessed. After the first 4 weeks of training, there was a significant improvement only in the balance test, whereas no additional changes were observed. However, after the second part of the training, the participants required significantly less time for the time-up-and-go test (P < 0.05), and improved the isometric hand grip, hip flexion and knee extension strength, as well as the leg press 1RM (P < 0.01). A significant reduction was also observed in the incidence of falls (P < 0.01). After 24 weeks of training cessation, abrupt decreases were observed in nearly all of the physical outcomes (P < 0.05). The exercise intervention improved strength, balance and gait ability in frail elderly patients with dementia after long-term physical restraint, and these benefits were lost after training cessation.


Asunto(s)
Demencia/rehabilitación , Ejercicio Físico/fisiología , Anciano Frágil , Fuerza Muscular/fisiología , Entrenamiento de Fuerza/métodos , Caminata/fisiología , Accidentes por Caídas/prevención & control , Accidentes por Caídas/estadística & datos numéricos , Anciano , Anciano de 80 o más Años , Demencia/fisiopatología , Demencia/psicología , Femenino , Estudios de Seguimiento , Marcha , Humanos , Masculino , Equilibrio Postural , Restricción Física , Factores de Tiempo , Resultado del Tratamiento
14.
Int J STD AIDS ; 24(11): 875-8, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23970602

RESUMEN

The prevalence of pharyngeal gonorrhoea in human immunodeficiency virus (HIV)-positive men who have sex with men (MSM) is not entirely known. We cultured the pharynx of 264 asymptomatic HIV-positive MSM in downtown Madrid. A questionnaire on sexual and drug use risk behaviours was also administered. Gonococci were isolated in 25 (9.5%). Among the whole study population, 65% had a history of sexual intercourse with two or more partners on a single day and 26% were involved in group sex with other men. Only 29% regularly used condoms in all sexual encounters and 63% used condoms only in insertive anal intercourse. When asked about oral sex, 89% of patients engaged in insertive and/or receptive oral sex and 86% recognized that they did not regularly request the use of condoms when practising "fellatio" on a partner. Cocaine, crystal methamphetamine or alcohol use and a previous history of ≥1 sexually transmitted infection were significantly more common among culture-positive patients. Gonococcal colonization of the pharynx was self-limited in patients that were not treated and re-cultured a mean 18.5 ± 5.2 days after diagnosis. Asymptomatic pharyngeal gonorrhoea is common among HIV-positive MSM and may contribute to the increasing epidemic of gonorrhoea in Madrid.


Asunto(s)
Gonorrea/epidemiología , Seropositividad para VIH/epidemiología , Homosexualidad Masculina/estadística & datos numéricos , Enfermedades Faríngeas/epidemiología , Conducta Sexual/estadística & datos numéricos , Adulto , Gonorrea/diagnóstico , Gonorrea/microbiología , Seropositividad para VIH/psicología , Encuestas Epidemiológicas , Humanos , Masculino , Neisseria gonorrhoeae/aislamiento & purificación , Enfermedades Faríngeas/microbiología , Prevalencia , Factores de Riesgo , Parejas Sexuales , Enfermedades de Transmisión Sexual/complicaciones , Enfermedades de Transmisión Sexual/epidemiología , España/epidemiología , Encuestas y Cuestionarios
15.
Int J Clin Exp Pathol ; 6(2): 199-211, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23330005

RESUMEN

XPG (Xeroderma pigmentosum group G complementing factor) is a protein associated with DNA repair and transcription. Point mutations in ERCC5, the gene coding for XPG, cause the cancer-prone disorder xeroderma pigmentosum (XP) while truncation mutations give rise to individuals with the combined clinical features of XP and Cockayne syndrome. Polymorphisms of ERCC5 or alterations in XPG mRNA expression were also associated to an increase risk of different cancers types and to prognosis of cancer patients. However, the expression of XPG protein in different normal or tumor human tissues is not well known. In the present work, we have validated an immunohistochemistry (IHC) assay for detection of expression levels of XPG protein in FFPE human tissue samples. We have also tested this IHC assay in different normal and tumor human tissues. On a microarray containing 28 normal cores, positive staining was observed in 60% of the samples. The highest staining was detected in adrenal gland, breast, colon, heart, kidney, thyroid and tongue. In tumors, positive staining was observed in 9 of 10 breast cancer samples and in all 5 ovarian cancer and 5 sarcomas samples. Subcellular localization was predominantly nuclear. The use of this validated methodology would help to interpret the role of XPG in tumorogenesis and its use as a possible prognostic or predictive factor.


Asunto(s)
Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Endonucleasas/genética , Endonucleasas/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Xerodermia Pigmentosa/genética , Xerodermia Pigmentosa/metabolismo , Glándulas Suprarrenales/fisiología , Mama/fisiología , Neoplasias de la Mama/genética , Síndrome de Cockayne/genética , Colon/fisiología , Femenino , Células HeLa , Corazón/fisiología , Humanos , Inmunohistoquímica/métodos , Inmunohistoquímica/normas , Riñón/fisiología , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , Neoplasias Ováricas/genética , Reproducibilidad de los Resultados , Sarcoma/genética , Glándula Tiroides/fisiología , Lengua/fisiología
16.
Inorg Chem ; 51(20): 10639-49, 2012 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-23005255

RESUMEN

Iron(III) amino triphenolate complexes with different substituents in the ortho-position of the phenolate moiety (R = H, Me, tBu, or Ph) have been synthesized by the reaction of iron(III) chloride and the sodium salt (Na(3)L(R)) of the requisite ligand. The complexes have been shown to be of either monomeric ([FeL(R)(THF)]) or dimeric ([FeL(R)](2)) nature by a combination of X-ray diffraction, (1)H NMR, solution magnetic susceptibility, and cyclic voltammetry studies. These analytical studies have shown that the monomeric and dimeric [FeL(R)] complexes behave distinctively, and that the dimer stability is a function of the ortho-positioned groups. Both the dimeric as well as monomeric complexes were tested as catalysts for the catalytic cycloaddition of carbon dioxide to oxiranes, and the data show that the monomeric complexes are able to mediate this conversion with significantly higher activities than the dimeric complexes. This difference in reactivity is controlled by the substitution pattern on the ligand L(R), and is in line with the catalytic requisite of binding of the epoxide substrate by the iron(III) center.


Asunto(s)
Dimerización , Hierro/química , Compuestos Organometálicos/química , Fenoles/química , Dióxido de Carbono/química , Electroquímica , Óxido de Etileno/química , Fenómenos Magnéticos , Compuestos Organometálicos/síntesis química
18.
Chem Commun (Camb) ; 47(17): 4911-3, 2011 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-21431225

RESUMEN

The concept of metal-ligand bifunctionality can be employed for an efficient activation of N-H bonds by well-defined ruthenium amido complexes. An enantioselective catalytic aza-Michael reaction was developed on the basis of this process, which gives rise to indoline ß-amino acids.

19.
Dalton Trans ; 40(13): 3352-64, 2011 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-21293818

RESUMEN

The use of olefin metathesis as a construction tool for multimetallic salen-based structures is described. The approach involves mono- and diallyl-functionalized metallosalen complexes that can be directly coupled by metathesis leading to dimetallic species or mixtures of linear and cyclic oligomers. The metathesis of bis-allyl Ni(salen) complexes has been studied in detail. At high concentration it is possible to selectively obtain di-Ni species rather than heavier oligomers while under dilute conditions cyclic rather than linear oligomers are preferentially obtained. A mono-allyl Zn(salphen) complex was efficiently coupled using metathesis to give the di-Zn(salphen) product, which was subsequently transmetalated with a variety of metals to yield dimetallic salens of potential catalytic interest. Finally, a tetranuclear Zn(4) macrocycle was also prepared using buildings blocks obtained by metathesis from commercially available precursors. The methods described herein allow for the facile construction of multi-centered Schiff base complexes of catalytic or supramolecular interest.

20.
Org Lett ; 11(22): 5218-21, 2009 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-19845369

RESUMEN

A modular and general synthetic method is disclosed for nonsymmetrical heterobimetallic bis-salphen structures starting from a series of synthetically convenient monometalated triimine precursors. This methodology permits the introduction of various combinations of metal ions within the bis-salphen framework potentially useful in multifunctional materials.


Asunto(s)
Etilenodiaminas/química , Etilenodiaminas/síntesis química , Metales Pesados/química , Compuestos Organometálicos/síntesis química , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular , Compuestos Organometálicos/química , Estereoisomerismo
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