72 results on '"Pedro Aguirre"'
Search Results
2. Location, morphology and invasiveness of lateral spreading tumors in the colorectum differ between two large cohorts from an eastern and western country
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Juan Gabriel Martínez-Cara, Liseth Rivero-Sánchez, Marco Antonio Alvarez-Gonzalez, Jesús M. González-Santiago, Felipe Ramos Zabala, Joaquin De La Peña, Kazuhiro Kaneko, Alberto Álvarez Delgado, Carla Jerusalén-Gargallo, Joaquín Rodríguez Sánchez, Orlando García-Bosch, Hiroaki Ikematsu, María Fraile, Carlos Guarner-Argente, Remedios Pardeiro, Shozo Osera, Maria Pellise, Alberto Herreros de Tejada, Jordi Gordillo, Oscar Nogales Rincon, David Martínez-Ares, Fernando Múgica, Carlos Marra-López, Bartolomé López Viedma, Carol J. Cobián, Eduardo Valdivielso Cortázar, Francisco Pérez-Roldán, Eduardo Redondo-Cerezo, Juan Colán-Hernández, Pedro Aguirre, Esteve Saperas, Manuel Rodríguez-Téllez, Berta Ibáñez, Santiago Soto, Eduardo Albéniz, and Leopoldo López-Rosés more...
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medicine.medical_specialty ,Colorectal cancer ,Mixed type ,Gastroenterology ,Polyp ,Internal medicine ,medicine ,Humans ,Neoplasm Invasiveness ,Intestinal Mucosa ,Lateral spreding tumors ,Retrospective Studies ,LST ,Hepatology ,business.industry ,Incidence (epidemiology) ,Cancer ,Histology ,Colonoscopy ,General Medicine ,medicine.disease ,Homogeneous ,Dysplasia ,Cohort ,Colorectal Neoplasms ,business - Abstract
Background and study aims Data from Japanese series show that surface morphology of laterally spreading tumors (LST) in the colon identifies lesions with different incidence and pattern of submucosal invasion. Such data from western countries are scarce. We compared clinical and histological features of LST in a western country and an eastern country, with special interest on mucosal invasiveness of LST, and investigated the effect of clinical factors on invasiveness in both countries. Patients and methods Patients with LST lesions ≥20 mm were included from a multicenter prospective registry in Spain and from a retrospective registry from the National Cancer Center Hospital East, Japan. The primary outcome was the presence of submucosal invasion in LST. The secondary outcome was the presence of high-risk histology, defined as high-grade dysplasia or submucosal invasion. Results We evaluated 1102 patients in Spain and 663 in Japan. Morphological and histological characteristics differed. The prevalence of submucosal invasion in Japan was six-fold the prevalence in Spain (Prevalence Ratio PR = 5.66; 95%CI: 3.96, 8.08), and the prevalence of high-risk histology was 1.5 higher (PR = 1.44; 95%CI: 1.31, 1.58). Compared to the granular homogeneous type and adjusted by clinical features, granular mixed, flat elevated, and pseudo-depressed types were associated with higher odds of submucosal invasion in Japan, whereas only the pseudo-depressed type showed higher risk in Spain. Regarding high-risk histology, both granular mixed and pseudo-depressed were associated with higher odds in Japan, compared with only the granular mixed type in Spain. Conclusion This study reveals differences in location, morphology and invasiveness of LST in an eastern and a western cohort. more...
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- 2022
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Catalog
3. Hydrogenation of biomass derivate catalysed by ruthenium (II) complexes containing phosphorus-nitrogen ligands under mild conditions
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Gonzalo Valdebenito, S. Parra-Melipan, Carol F. Dinamarca, V. López, A. Vega, G. Abarca, and Pedro Aguirre
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Process Chemistry and Technology ,Physical and Theoretical Chemistry ,Catalysis - Published
- 2023
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4. Selective hydrogenation of furfural to furfuryl alcohol catalysed by ruthenium complexes containing phosphorus‐nitrogen ligands
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Vicente López, Pedro Aguirre, Sergio A. Moya, Eryck García, Sebastián Parra-Melipán, Gonzalo Valdebenito, Camila Negrete-Vergara, Braulio Aranda, and Andrés Vega
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Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Phosphorus ,chemistry.chemical_element ,Organic chemistry ,Homogeneous catalysis ,General Chemistry ,Furfural ,Nitrogen ,Ruthenium ,Furfuryl alcohol - Published
- 2021
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5. Hydrogenation of imines catalyzed by ruthenium(II) complexes containing phosphorus-nitrogen ligands via hydrogen transfer reaction
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Braulio Aranda, Gonzalo Valdebenito, Sebastián Parra-Melipán, Vicente López, Sergio Moya, Andrés Vega, and Pedro Aguirre
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Process Chemistry and Technology ,Physical and Theoretical Chemistry ,Catalysis - Published
- 2022
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6. Massive upper gastrointestinal bleeding secondary to an esophago-arterial fistula (arteria lusoria)
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Andrea Guerro Moya, Pedro Aguirre, and Eduardo Valdivielso Cortázar
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Male ,medicine.medical_specialty ,Fistula ,medicine.medical_treatment ,Cardiovascular Abnormalities ,Subclavian Artery ,Tracheoesophageal fistula ,Stoma (medicine) ,medicine ,Humans ,cardiovascular diseases ,Arteria lusoria ,Computed tomography angiography ,medicine.diagnostic_test ,business.industry ,Gastroenterology ,Stent ,General Medicine ,Middle Aged ,medicine.disease ,Surgery ,Laryngectomy ,surgical procedures, operative ,Angiography ,Upper gastrointestinal bleeding ,business ,Gastrointestinal Hemorrhage - Abstract
A 50-year-old patient with a history of hypopharyngeal cancer, laryngectomy, adjuvant chemoradiotherapy and incompetent tracheoesophageal fistula was admitted for elective pharingostomal surgery. During the surgery, he presented esophageal bleeding with hemodynamic instability. After stabilization, a gastroscopy was performed through the stoma, showing arterial bleeding 4-5 cm distal to the stoma, which was controlled with three hemostatic clips. After four hours, the patient presented a new episode of bleeding with hemodynamic instability and a Sengstaken-Blakemore tube was placed that stopped the bleeding. Computed tomography angiography (CT angiography) was performed, which showed an aberrant right subclavian artery with a retroesophageal pathway, in close contact with the area where the clips were placed. An endovascular stent was placed in the right subclavian artery with control of the bleeding after removal of the Sengstaken-Blakemore tube. The patient was discharged seven days later. more...
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- 2021
7. Catalytic activity of a new Ru(<scp>ii</scp>) complex for the hydrogen transfer reaction of acetophenone and N-benzylideneaniline: synthesis, characterization and relativistic DFT approaches
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Pedro Aguirre, C. Pérez-Zúñiga, Mauricio Yáñez-S, Plinio Cantero-López, César Zúñiga, Ramiro Arratia-Pérez, C. Negrete-Vergara, and Sergio A. Moya
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Valence (chemistry) ,Hydride ,Ligand ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Ruthenium ,Crystallography ,chemistry.chemical_compound ,Chemical bond ,chemistry ,Nucleophile ,Materials Chemistry ,0210 nano-technology ,Acetophenone - Abstract
The synthesis and characterization of a new ruthenium(II) complex containing a hemilabile P^N-ligand are reported. The catalytic activity of this complex was evaluated in the hydrogen transfer reaction of acetophenone and N-benzylideneaniline achieving conversions around 35 and 96% respectively. Condensed Fukui functions in a relativistic DFT scheme show that the regions for the electrophilic (f−) and nucleophilic (f+) attack are Cl− in the axial position, regions belonging to the P^N ligand and the metal center. The lability of the ligands is determined using different theoretical approaches like Morokuma–Ziegler energy decomposition analysis combined with the Extended Transition State with Natural Orbitals of Chemical Valence (ETS-NOCV). The major lability for the –Cl ligand (protic environment) is ideal for designing a new ruthenium hydride complex, suitable for catalytic applications. The σ-donation determines the degree of covalence of the chemical bond involving a lower trend to dissociate, as is the case of the P^N-ligand. The most important excitation energies appear in the region between 250 and 410 nm and are assigned to ligand to ligand charge transfer (LLCT) and metal to ligand charge transfer (MLCT) transitions. more...
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- 2019
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8. Valorization of furfural using ruthenium (II) complexes containing phosphorus-nitrogen ligands under homogeneous transfer hydrogen condition
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Sergio A. Moya, Vicente López, Pedro Aguirre, Braulio Aranda, Gonzalo Valdebenito, and Sebastián Parra-Melipán
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Hydrogen ,Formic acid ,Process Chemistry and Technology ,chemistry.chemical_element ,Substrate (chemistry) ,Furfural ,Catalysis ,Furfuryl alcohol ,Ruthenium ,chemistry.chemical_compound ,chemistry ,Cannizzaro reaction ,Organic chemistry ,Physical and Theoretical Chemistry - Abstract
In this paper, we report the catalytic activity of a series of ruthenium (II) complexes containing phosphorus-nitrogen bidentated (P-N) ligands in the hydrogenation of furfural via hydrogen transfer reaction using two hydrogen donor sources: 2-propanol in basic medium and formic acid under mild conditions. The results showed that all the ruthenium complexes studied are catalytically active in the hydrogenation of furfural by hydrogen transfer reaction; they showed 100% conversion with both hydrogen sources. However, selectivities towards the formation of furfuryl alcohol were better when formic acid was used. It was also found that the reaction studied in a basic medium competes with the Cannizzaro reaction, obtaining furfuryl alcohol and furoic acid in a 70/30 ratio; on the other hand, using formic acid as the hydrogen source yields furfuryl alcohol with 100% selectivity. Although formic acid can be used as a hydrogen source successfully. The optimal substrate/acid ratio was found to be 1:1, as a higher concentration of formic acid can cause catalyst decomposition. The yielded products, furfuryl alcohol and furoic acid, obtained from renewable sources, have multiple applications in the organic chemical industry, replacing or complementing similar fossil-derived products. more...
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- 2021
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9. Tuning the photophysical properties of a (P,N)ReI complex by adding a –NH– fragment into a P,N-bidentate ligand: The case of [P,N-{(C6H5)2(C5H4N)NHPRe(CO)3Br]
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Juan Carlos Palma, Marjorie Cepeda-Plaza, Nancy Pizarro, Pedro Aguirre, Jorge Manzur, Pablo Mella, Andrés Vega, and Germán Günther
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010405 organic chemistry ,Chemistry ,Ligand ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,Reaction rate constant ,Computational chemistry ,Molecular vibration ,Excited state ,Materials Chemistry ,Physical and Theoretical Chemistry ,Cyclic voltammetry ,Absorption (chemistry) ,Ground state ,Luminescence - Abstract
The spectroscopic, electrochemical and photophysical properties of the new complex [P,N-{(C6H5)2(C5H4N)NHP}Re(CO)3Br] (RePNN) are reported. The UV–Vis spectrum in dichloromethane (DCM) shows an absorption maximum centered at 300 nm and a shoulder at 350 nm. These absorption bands have been characterized, having a πpy → π∗py and a MLCT character. Excitation at the first wavelength (higher energy) leads to an emission band centered at 365 nm. Cyclic voltammetry shows a fully irreversible oxidation wave around +1.45 V, assigned to ReI/ReII couple, whereas two irreversible reduction signals centered at −0.75 and −1.20 V are assigned to ligand reduction processes. The photophysical results show that emission from the RePNN complex comes exclusively from the ligand. The MLCT excited state shows to be non-emissive by coupling to vibrational modes leading to non-radiative decay path to ground state. The luminescent decay fits to a bi-exponential function. DFT calculations suggest that intra-ligand πpy → π∗py and πpy → π∗ph excited states may account for the existence of these two decay lifetimes. The additional –NH– fragment present in the 2-(diphenylphosphinoamino)pyridine ligand compared to 2-pyridylphosphine, makes it more flexible and in consequence, enhances the non-radiative decay rate constant from the 3MLCT to the ground state in the RePNN complex compared to those of 2-pyridylphosphine, [P,N-{(C6H5)2(C5H4N)PRe(CO)3Br] (RePN). more...
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- 2016
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10. Catalytic activity in transfer hydrogenation using ruthenium (II) carbonyl complexes containing two 1,8-naphthyridine as N-monodentate ligands
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Juana Gajardo, Andrés Ibañez, Sergio A. Moya, Hubert Le Bozec, Véronique Guerchais, Juan Carlos Araya, Pedro Aguirre, Universidad San Sebastian, Universidad Central de Chile, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universidad de Santiago de Chile [Santiago] (USACH), This work has been supported by ECOS-CONICYT (Action C14E02) and Fondecyt 1160505. J. C. Araya and J. Gajardo gratefully acknowledge CONICYT-Chile for their doctoral fellowships. S.A.M acknowledges the financial support provided by DICYT-USACH-Chile. This research has been performed as part of the Chilean-French 'Joint Laboratory for Multifunctional Molecules and Materials' (LIA MIF)., Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA) more...
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Denticity ,chemistry.chemical_element ,Homogeneous catalysis ,010402 general chemistry ,Transfer hydrogenation ,01 natural sciences ,Medicinal chemistry ,8-Naphthyridine complexes ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Octahedral molecular geometry ,Materials Chemistry ,[CHIM]Chemical Sciences ,Physical and Theoretical Chemistry ,Ruthenium (II) ,Acetophenone ,010405 organic chemistry ,Chemistry ,0104 chemical sciences ,3. Good health ,Ruthenium ,Selectivity - Abstract
International audience; A new series of novel complexes of type cis-[Ru(CO)2Cl2(L)2], L = 2-phenyl-1,8-naphthyridine, 2-(4′-nitrophenyl)-1,8-naphthyridine, 2-(4′-bromophenyl)-1,8-naphthyridine, 2-(4′-methylphenyl)-1,8-naphthyridine, 2-(3′-methoxyphenyl)-1,8-naphthyridine, 2-(2′-methoxyphenyl)-1,8-naphthyridine and 2-(4′-methoxyphenyl)-1,8-naphthyridine have been successfully synthesized and characterized. We found that the complexes can be directly synthesized from [RuCl2(CO)2]2 with high yield. The crystallographic structures of complex cis-[RuCl2(CO)2(2-(4′-methoxyphenyl)-1,8-naphthyridine-κN8)2] and cis-[RuCl2(CO)2(2-(2′-methoxyphenyl)-1,8-naphthyridine-κN8)2] have been established by X-ray single crystal diffraction studies, which indicate an octahedral geometry with two 1,8-naphthyridine ligands coordinated to the metal in a N-monodentate fashion. The ruthenium(II) complexes have been studied as catalysts in the transfer hydrogenation of acetophenone. We found that complexes show moderate activities and a 100% selectivity. The best turnover frequency (390 h−1) is found for cis-[RuCl2(CO)2(2-(4′-methoxyphenyl)-1,8-naphthyridine-κN8)2] when the substrate/catalysis ratio was 1000/1. The catalytic conditions were optimized using different substrate/catalyst and base/catalyst ratios. © 2018 more...
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- 2019
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11. A novel copper(<scp>ii</scp>)–lanthanum(<scp>iii</scp>) metal organic framework as a selective catalyst for the aerobic oxidation of benzylic hydrocarbons and cycloalkenes
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Sergio Navalón, Mercedes Alvaro, Pedro Aguirre, Patricio Cancino, Evgenia Spodine, Hermenegildo García, Andrea Santiago-Portillo, and Andrés Vega
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010405 organic chemistry ,Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Homogeneous catalysis ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Catalysis ,Coupling reaction ,0104 chemical sciences ,Heteronuclear molecule ,Catalytic cycle ,Polymer chemistry ,Lanthanum ,Metal-organic framework - Abstract
The synthesis and structure of a novel heteronuclear CuII and LaIII metal organic framework (MOF) having pyridinedicarboxylic acid (CuLa-MOF) is reported. The obtained MOF with the formula {[Cu0.5La2(HPDC)(PDC)2(SO4)(H2O)2]H2O}n (PDC: 3,5-pyridinedicarboxylate) has a 3D non-porous lattice with a single type of octahedrally coordinated CuII and two distinct nonacoordinated LaIII ions, with sulphate being a linker between the CuII and LaIII centers. CuLa-MOF exhibits catalytic activity to promote the aerobic autooxidation of benzylic hydrocarbons and the aerobic oxidation of cycloalkenes. Compared with a homogenous catalyst, Cu(OAc)2, CuLa-MOF, as a heterogeneous catalyst, exhibits similar activity, but the solid is recyclable with some minor decrease in activity from the first to the second catalytic cycle; after which, a steady activity is observed, as determined by the coincidence of temporal evolution of the reaction upon reuse. more...
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- 2016
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12. Synthesis and characterization of ruthenium(II) complexes incorporating 4′-phenyl-terpyridine and triphenylphosphine
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M. Yañez, C. Pérez-Zúñiga, R. López, Sergio A. Moya, and Pedro Aguirre
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Hydride ,Ligand ,chemistry.chemical_element ,Nuclear magnetic resonance spectroscopy ,Photochemistry ,Ruthenium ,Metal ,chemistry.chemical_compound ,Crystallography ,chemistry ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Hypsochromic shift ,Physical and Theoretical Chemistry ,Terpyridine ,Triphenylphosphine - Abstract
The syntheses of two new series of ruthenium(II) complexes incorporating substituted 4′-phenyl-terpyridine, triphenylphosphine, and chloride (A Series) or hydride (B Series) are reported. In both series 4′-phenyl-terpyridine incorporated substituents of varying electronic character at the 4-position: 4′-(4-chlorophenyl)-2,2′ : 6′,2″-terpyridine (ClPh-tpy); 4′-(4-nitrophenyl)-2,2′ : 6′,2″-terpyridine (NO2Ph-tpy) and 4′-(4-methoxyphenyl)-2,2′ : 6′,2″-terpyridine (OMePh-tpy). The complexes have been characterized by elemental analysis and UV–vis, IR, and NMR spectroscopy and their electrochemical properties studied. The substituents on the 4′-phenyl-terpyridine ligand influence the properties of the metal center. For all complexes prepared, λmax of a characteristic low energy band in the UV–vis spectrum was found to move to shorter wavelengths as the solvent polarity increased (a hypsochromic shift). For the B series complexes, the low energy band was broader and undergoes a small shift to lower frequencies ... more...
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- 2015
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13. Methoxycarbonylation of Styrene Using a New Type of Palladium Complexes Bearing P,N-donor Ligands as Catalysts
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Sergio A. Moya, Gabriel Abarca, J. Carles Bayón, Kareen Brown, and Pedro Aguirre
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Denticity ,Ligand ,Regioselectivity ,chemistry.chemical_element ,Homogeneous catalysis ,General Chemistry ,Medicinal chemistry ,Catalysis ,Styrene ,chemistry.chemical_compound ,chemistry ,Organic chemistry ,Organometallic chemistry ,Palladium - Abstract
Palladium complexes of the type [Pd(L)Cl(PPh3)]Cl (L = 2-diphenylphosphinoamino)pyrimidine, or 2-diphenylphosphinoaniline), generated in situ by addition of one equivalent of PPh3 to the corresponding neutral complexes [Pd(L)Cl2], were tested as catalysts for the methoxycarbonylation of styrene. The catalyst containing the pyrimidinyl ligand shows almost complete chemo- and regioselectivity together with a high conversion rate. However, in identical conditions, the [Pd(Ph2PNHC6H4PPh2)Cl2] complex, where the P,N-ligand has been replaced by a related bidentate P-donor one, shows a significantly lesser performance. more...
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- 2015
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14. Ruthenium(II)-carbonyl complexes containing two N-monodentate 1,8-naphthyridine ligands active catalysis in transfer hydrogenation reactions
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Juana Guajardo, Véronique Guerchais, Andrés Vega, Andrés Ibañez, Sergio A. Moya, Pedro Aguirre, Universidad de la frontera [Chile], Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Universidad Andrés Bello [Santiago] (UNAB), Universidad de Santiago de Chile [Santiago] (USACH), Fondo Nacional de Desarrollo Cientifico y Tecnologico [1160505], ECOS-CONICYT [C14E02], Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) more...
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crystal structure ,Denticity ,chemistry.chemical_element ,catalytic activity ,Crystal structure ,010402 general chemistry ,Transfer hydrogenation ,01 natural sciences ,Chloride ,Medicinal chemistry ,hydrogen-transfer reaction ,Catalysis ,Inorganic Chemistry ,Hydrogen-transfer reaction ,Materials Chemistry ,medicine ,[CHIM]Chemical Sciences ,Naphthyridine ligand ,Physical and Theoretical Chemistry ,010405 organic chemistry ,Chemistry ,naphthyridine ligand ,Condensed Matter Physics ,Catalytic activity ,0104 chemical sciences ,3. Good health ,Ruthenium ,ruthenium(II) ,Yield (chemistry) ,Selectivity ,Ruthenium(II) ,medicine.drug - Abstract
The reaction of 2-aminonicotinaldehyde with 2- or 4-methoxyacetophenone in basic media leads to the new ligands 2-(4-methoxyphenyl)-1,8-naphthyridine and 2-(2-methoxyphenyl)-1,8-naphthyridine, respectively, in high yield. The reaction of these naphthyridine derivatives with [RuCl2(CO)2] n leads to the respective complexes cis-dicarbonyldichloridobis[2-(4-methoxyphenyl)-1,8-naphthyridine-κN 8]ruthenium(II) and cis-dicarbonyldichloridobis[2-(2-methoxyphenyl)-1,8-naphthyridine-κN 8]ruthenium(II), both [RuCl2(C15H12N2O)2(CO)2], in good yield. Both ruthenium(II) complexes display a slightly distorted octahedron with two cis carbonyl, two cis chloride and two cis naphthyridine ligands, the latter coordinated in a monodentate fashion through the N atom in the 8-position. Both complexes exhibit a moderate catalytic activity in the hydrogen-transfer reaction from propan-2-ol to acetophenone in the presence of a base, with 100% selectivity. more...
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- 2018
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15. Luminescent bis-cyclometallated iridium(III) complexes containing phosphine-based ligands: Influence of the P^N bridge
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J. A. Gareth Williams, Hubert Le Bozec, Muriel Escadeillas, Loïc Toupet, Pedro Aguirre, Mickaële Bonneau, Véronique Guerchais, Braulio Aranda, Sergio A. Moya, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile = University of Chile [Santiago] (UCHILE), Facultad de Química y Biología, Department of Chemistry, Durham University, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), This work was supported by LIA CNRS 836 Chili (MIF) and FONDECYT (# 1120149). B.A. gratefully acknowledges the French Embassy in Chile for a grant., Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS) more...
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Luminescence ,Imine ,Blue phosphors ,chemistry.chemical_element ,Crystal structure ,[CHIM.INOR]Chemical Sciences/Inorganic chemistry ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Pyridine ,Polymer chemistry ,Materials Chemistry ,Phosphine ligands ,Iridium ,Physical and Theoretical Chemistry ,[PHYS]Physics [physics] ,Iridium complexes ,010405 organic chemistry ,Ligand ,Quinoline ,Cationic polymerization ,0104 chemical sciences ,chemistry ,Bis-cyclometallated complexes ,Phosphine - Abstract
The crystal structures of 1, 2 and 3 have been deposited at the Cambridge Crystallographic Data Centre and allocated the deposition numbers CCDC-938912, CCDC-907692, and CCDC-912857, respectively. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.; International audience; Three cationic bis-cyclometallated iridium complexes [Ir(C^N-ppyMe)2(P^N)][PF6](1-3) with 4-methyl-2-phenylpyridine (ppyMe) as the C^N-cyclometallated ligands and 8-(diphenylphosphino)quinoline (Ph2Pqn, L1), 2-(diphenylphosphinoamino)pyridine (Ph2PNHpy, L2) or 2-(diphenylphosphinoamino) pyrimidine (Ph2PNHpym, L3) as P^N-ligands, were prepared, and their crystal structures and photoluminescence were investigated. The substitution of an "aromatic CAr" (of a quinolyl group) by an "NH" bridge between the phosphine and imine ligating units of the P^N ligand dramatically changes the luminescence characteristics of the resulting complexes. The complexes 2-3 featuring the P-NH-N ligand emit in the blue region, whereas complex 1 incorporating the P-CAr-N unit displays orange photoluminescence. more...
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- 2015
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16. On ecosystems dynamics
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Milan Stehlík, Pavlina K. Jordanova, Pedro Aguirre, Sebastian Torres-Leiva, Jozef Kiseľák, Z Sadovsky, Andrés Rivera, Stéphane Girard, Departamento de Estadistica [Valparaiso], Universidad de Valparaiso [Chile], Department of Applied Statistics [Linz], Johannes Kepler Universität Linz (JKU), Departamento de Matematica [Valparaiso], Universidad Tecnica Federico Santa Maria [Valparaiso] (UTFSM), Modelling and Inference of Complex and Structured Stochastic Systems (MISTIS ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Faculty of Mathematics and Computer Science [Schumen], Shumen University [Schumen], Institute of Mathematics [Kosice, Slovakia], P.J. Safarik University, Slovak Academy of Science [Bratislava] (SAS), and Centro de Estudios Científicos (CECs) more...
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010504 meteorology & atmospheric sciences ,chaos ,Climate change ,Monotonic function ,Dynamical system ,01 natural sciences ,Physics::Geophysics ,010104 statistics & probability ,[MATH.MATH-ST]Mathematics [math]/Statistics [math.ST] ,0101 mathematics ,Extreme value theory ,autonomous system ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,geography ,stochasticity ,geography.geographical_feature_category ,Ecology ,Ecological Modeling ,Estimator ,determinism ,Glacier ,Function (mathematics) ,Snow ,Guanaco glacier ,snow extremes ,13. Climate action ,Climatology ,Environmental science - Abstract
International audience; We show how a dynamical system given by a t-score function for some class of monotonic data transformations generates consistent extreme value estimators. The variation of their values increases the uncertainty of proper assessment of climate change. Two important examples illustrate the methodology: mass balance measurements on Guanaco glacier, Chile, and extreme snow loads in Slovakia. We experience singular learning of the transitions in ecosystems. more...
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- 2017
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17. New case of duplicate or redundant publication in different languages
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Gabriela Merma-Flores, Pedro Aguirre-Alcántara, Nicolás Reyes-Rodríguez, Jessica Altamirano-Gamarra, and César Silva-Barboza
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lcsh:R5-920 ,Political science ,lcsh:R ,Public Health, Environmental and Occupational Health ,MEDLINE ,lcsh:Medicine ,General Medicine ,lcsh:Medicine (General) ,Humanities ,Food labeling - Published
- 2018
18. New palladium (II) complexes containing phosphine-nitrogen ligands and their use as catalysts in aminocarbonylation reaction
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Sofia Ramirez-Lopez, Gonzalo Valdebenito, Pedro Aguirre, Andrés Vega, Sergio A. Moya, and Braulio Aranda
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Inorganic Chemistry ,chemistry.chemical_classification ,chemistry.chemical_compound ,chemistry ,Aryl halide ,Polymer chemistry ,chemistry.chemical_element ,General Chemistry ,Nitrogen ,Phosphine ,Catalysis ,Palladium - Published
- 2019
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19. Transfer hydrogenation of N-benzylideneaniline catalyzed by ruthenium complexes with pincer-type phosphorus nitrogen ligands using propan-2-ol as the hydrogen source
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Sergio A. Moya, M. Fuentealba, Véronique Guerchais, K. Brown, Pedro Aguirre, C. Negrete-Vergara, V. Artigas, Universidad de Santiago de Chile [Santiago] (USACH), Universidad de Chile = University of Chile [Santiago] (UCHILE), Pontificia Universidad Católica de Valparaíso (PUCV), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ECOS-CONICYT [Action C14E02], Fondecyt-Chile [1160505], Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) more...
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Hydrogen ,010405 organic chemistry ,Chemistry ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Process Chemistry and Technology ,Noyori asymmetric hydrogenation ,chemistry.chemical_element ,Substrate (chemistry) ,General Chemistry ,[CHIM.CATA]Chemical Sciences/Catalysis ,010402 general chemistry ,Transfer hydrogenation ,01 natural sciences ,Medicinal chemistry ,Nitrogen ,hydrogenation catalysis ,Catalysis ,0104 chemical sciences ,Pincer movement ,Ruthenium ,hydrogenation propan-2-ol ,Organic chemistry ,ruthenium catalysts - Abstract
International audience; Ruthenium complexes containing phosphorus-nitrogen, pincer-type (NPN) ligands show high activities and selectivities in the transfer hydrogenation of N-benzylideneaniline using propan-2-ol as the hydrogen source. Such is the case of complexes RuCl2PPh3(PPh(NHPy)(2)) (1) and RuCl2PPh3(PPh(NHPyMe)(2)) (2) which also show TOFs 5989 h(-1) and 5928 h(-1), respectively. These remarkable results were obtained after only 10 min of reaction using a 1000/1 substrate/catalyst ratio. more...
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- 2017
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20. Catalytic hydrogenation of N-benzylideneaniline using a new complex of ruthenium(II) derived from 2-ferrocenyl-1,8-naphthyridine
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Braulio Aranda, Mauricio Fuentealba, Sergio A. Moya, Pedro Aguirre, and César Zúñiga
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Chemistry ,Substrate (chemistry) ,Noyori asymmetric hydrogenation ,chemistry.chemical_element ,Hydrogen transfer ,Medicinal chemistry ,Catalysis ,Ruthenium ,Inorganic Chemistry ,Elemental analysis ,Materials Chemistry ,Organic chemistry ,Physical and Theoretical Chemistry ,Spectroscopy ,Catalytic hydrogenation - Abstract
2-Ferrocenyl-1,8-naphthyridine (1) and cis,cis,cis-dicarbonyl-dichloro-bis (2-ferrocenyl-1,8-naphthyridine) ruthenium(II) complex (2) have been synthesized and characterized by IR, 1H-NMR spectroscopy and elemental analysis. The structure of the compounds was determined by X-ray analysis. The complex (2) showed catalytic activity in the hydrogenation reaction of N-benzylideneaniline by hydrogen transfer with conversions between 89% and 33% for catalyst/substrate relations 200/1 and 400/1. more...
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- 2011
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21. [Cu(H2btec)(bipy)]∞: Reusable Metal Organic Polymer Catalyst for Epoxidation Reactions
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Diego Venegas-Yazigi, Kareen Brown, Evgenia Spodine, Pedro Aguirre, and Verónica Paredes-García
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Materials science ,Polymers and Plastics ,Coordination polymer ,Catalyst support ,Organic Chemistry ,Inorganic chemistry ,Cyclohexene ,Condensed Matter Physics ,Catalyst poisoning ,Styrene ,Catalysis ,chemistry.chemical_compound ,chemistry ,Atom economy ,Materials Chemistry ,Selectivity - Abstract
Summary: The search of new inorganic materials with better catalytic properties is an important field of research. Reusability, efficiency and atom economy correspond to the main parameters to characterize a catalyst. In this work, we inform the effectiveness of [Cu(H2btec)(bipy)]∞ (H4btec = 1,2,4,5-benzenetetracarboxylic acid) as an heterogeneous coordination polymer catalyst for the oxidation of olefins. The catalyst exhibits good atom economy, high turnover numbers and good selectivity for a ratio of 4000/1 substrate/catalyst for cyclohexene and styrene oxidation. Furthermore, the catalyst was recycled and reused for seven consecutive cycles, retaining the structural integrity and effectiveness as catalyst in all the performed experiments. more...
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- 2011
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22. RUTHENIUM CARBONYL CLUSTERS AS CATALYSTS IN THE WATER GAS SHIFT REACTIONS
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Pedro Aguirre, Rebeca Sartori, Renato Sariego, Sergio A. Moya, and Pierre H. Dixneuf
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Chemistry ,Polymer chemistry ,Nitro ,Copolymer ,Organic chemistry ,chemistry.chemical_element ,General Chemistry ,Water-gas shift reaction ,Catalysis ,Ruthenium - Abstract
The catalytic activity of Ru3(CO)9 L3 (L = arylphosphine) in the WGSR and in the reduction of nitro derivatives to amines is studied. The same complex is supported in polystyrene-divinylbenzene copolymer (PSDVB) and the catalytic activity of this heterogeneous material on the fore mentioned reactions is herein studied. In the same way, Ru3(CO)12 is reacted with PSDVB, previously functionalized with 1,2-ethylenediamine, giving an active catalyst for these reactions. more...
- Published
- 2010
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23. Magnetic and catalytic properties of the 2D copper(II) functionalized VPO hybrid system [{Cu(bpy)}2(VO)3(PO4)2(HPO4)2]·2H2O
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Raul Cardoso-Gil, Evgenia Spodine, Pedro Aguirre, Karina Muñoz-Becerra, Walter Schnelle, Diego Venegas-Yazigi, Carolina Aliaga, Verónica Paredes-García, Kareen Brown, Andrés Vega, and Ruediger Kniep
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Inorganic chemistry ,Cyclohexene ,Vanadium ,chemistry.chemical_element ,Heterogeneous catalysis ,Copper ,Styrene ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,chemistry ,Materials Chemistry ,Antiferromagnetism ,Physical and Theoretical Chemistry ,Chemoselectivity - Abstract
The hybrid 2D compound [{Cu(bpy)} 2 (VO) 3 (PO 4 ) 2 (HPO 4 ) 2 ]·2H 2 O (1) , has been investigated due to its interesting magnetic and catalytic properties. Compound (1) acts as an efficient catalyst in the epoxidation of cyclohexene and styrene. The chemoselectivity towards the epoxidation of cyclohexene is notoriously higher than the one observed towards styrene. The bulk antiferromagnetic behaviour of [{Cu(bpy)} 2 (VO) 3 (PO 4 ) 2 (HPO 4 ) 2 ]·2H 2 O (1) can be well described with a pentanuclear model, using five J values. Both antiferromagnetic and ferromagnetic interactions mediated by phosphate bridges are found to be present in this hybrid copper(II)–vanadium(IV) material. more...
- Published
- 2010
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24. GELATION OF N3P3[NH(CH2)3Si(OEt)3]6-n [X]n X = NH(CH2)3Si(OEt)3, NCH3(CH2)3CN AND OC6H4(CH2)CN, n = 0 or 3 at the LIQUID/AIR/INTERFACE
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Carlos Díaz, Pedro Aguirre, Nicolás Yutronic, and María Luisa Valenzuela
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Phosphazenes ,Sol-gel ,cyclotriphosphazenes ,Chemistry ,Nanoparticle ,General Chemistry ,silica nanoparticles ,nanostructure materials ,Silica nanoparticles ,Liquid air ,Physical chemistry ,Organic chemistry ,Solution process ,Pyrolysis ,Tem analysis - Abstract
The compounds N3P3[NH(CH2)3Si(OEt)3]6 (1), N3P3[NH(CH2)3Si(OEt)3]3[NCH3(CH2)3CN]3 (2) and N3P3[NH(CH2)3Si(OEt)3]3 [HOC6H4(CH2)CN]3 (3) undergo slow gelation at the interface oil/air at low temperatures to give perfect gels G1, G2 and G3 respective ly. TEM analysis reveals nanoparticles of silica with mean size of about 10 nm. Pyrolysis under air at 800 °C of these gels affords a mixture of mainly Si5(PO4)6O, SiP2O7 and SiO2. Gelation and pyrolysis products were characterized by IR, solid-state NMR, TEM, SEM-EDAX microscopy and X-ray diffraction. The sol-gel process in the interface liquid /air is discussed in comparison with the usual sol-gel solution process. more...
- Published
- 2010
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25. Methoxycarbonylation of Styrene Catalyzed by Palladium Complexes with Ferrocene Derivatives Containing Nitrogen and Phosphine Ligands
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Cesar Zúñiga, Pedro Aguirre, and Sergio A. Moya
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Denticity ,Ligand ,chemistry.chemical_element ,General Chemistry ,Medicinal chemistry ,Catalysis ,chemistry.chemical_compound ,chemistry ,Organic chemistry ,Triphenylphosphine ,Metallocene ,Organometallic chemistry ,Phosphine ,Palladium - Abstract
The catalytic behaviour of different complexes of Palladium(II) containing mono or bidentate phosphorus or nitrogen ligands in the methoxycarbonylation reaction is examined. The pre-catalysts containing either a diphosphine ligand possessing a ferrocenyl backbone or a naphthyridine ligand attached to the same ferrocenyl backbone showed different catalytic activity for the reaction. Complexes containing the 1,1-bis(diphenylphosphino)ferrocene (dppf) ligand showed a better catalytic activity than the complex having the naphthyridine ligand in its structure. Various effects of the addition of triphenylphosphine to these pre-catalysts were observed. More than 99% conversion was achieved in the methoxycarbonylation of styrene using Pd(II) catalysts with ferrocenyl chelate derivatives, mostly with the Pd(dppf)Cl2, [Pd(dppf)(MeCN)2](BF4)2 and [Pd(dppf)PPh3](BF4)2 complexes without the presence of triphenylphosphine as is usual in this reaction. The reactions were carried out under mild pressure and temperature conditions. Complexes of the type Pd(dppf)Cl2, [Pd(dppf)(MeCN)2](BF4)2 and [Pd(dppf)PPh3](BF4)2 were used as catalysts for the Methoxycarbonylation of styrene using mild pressure and temperature condition. The catalysts system showed more than 99% conversion in reactions without the presence of triphenylphosphine. more...
- Published
- 2009
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26. New Aldehydes by Catalytic Diene Cycloisomerisations
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Teodor Parella, Fanny Grau, Elisabet Duñach, J. Carles Bayón, and Pedro Aguirre
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chemistry.chemical_compound ,Diene ,Ligand ,Chemistry ,Intramolecular force ,Organic Chemistry ,Organic chemistry ,Regioselectivity ,Nuclear magnetic resonance spectroscopy ,Physical and Theoretical Chemistry ,Hydroformylation ,Catalysis - Abstract
The Rh-catalysed hydroformylation of isopropylidenecyclohexane derivatives obtained by intramolecular diene cyclisations affords the corresponding aldehydes in good yields and in a completely chemo- and regioselective manner. Diastereoselectivities of ca. 90 % were achieved for all substrates when a bulky phosphite was used as the Rh ligand. Thestereochemical outcomes of the hydroformylation reactions were established by detailed NMR studies. The olfactory evaluation of the different aldehydes is also presented.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) more...
- Published
- 2008
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27. Hydroesterification versus hydroformylation–acetalization of 1-hexene catalyzed by soluble carbonylrhodium complexes of pyridine ligands
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Clementina Longo, Fernando Hung-Low, Alvaro J. Pardey, Sergio A. Moya, Gabriela C. Uzcátegui, Angel B. Rivas, Marisol C. Ortega, Pedro Aguirre, and Jorge Yáñez
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Nucleophilic addition ,Process Chemistry and Technology ,chemistry.chemical_element ,Medicinal chemistry ,Catalysis ,Water-gas shift reaction ,Heptanal ,Rhodium ,chemistry.chemical_compound ,chemistry ,Hexene ,Organic chemistry ,Methanol ,Physical and Theoretical Chemistry ,Hydroformylation - Abstract
The rhodium(I) complexes, cis-[Rh(CO)2(amine)2](PF6) (amine = pyridine, 2-picoline, 3-picoline, 4-picoline, 3,5-lutidine or 2,6-lutidine) dissolved in methanol under carbon monoxide atmosphere are effective catalysts for the hydroesterification and hydroformylation–acetalization of 1-hexene. In the presence of these soluble complexes, 1-hexene, CO and methanol give methyl-heptanoate and 1,1-dimethoxy-heptane as major products, and minor amounts of heptanal. The acetal product comes from the nucleophilic addition reaction of the methanol with the formed heptanal. Gaseous by-products (H2 and CO2) from the catalysis of the water–gas shift reaction (WGSR) are also observed. The reaction products distribution depends on the nature of the coordinated amine to the rhodium center. The effects of the reaction variables such as CO pressure, temperature, catalyst concentration, 1-hexene/Rh molar ratio and reaction medium, were also examined. These data are discussed in terms of catalytic cycles, and it is concluded that common Rh–H catalytic species are involved. more...
- Published
- 2005
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28. Intramolecular Redox Processes Induced in Biquinoline-Centered and Metal to Ligand Charge Transfer Excited States of Ru(II)-(4,4‘-bipyridine)-Re(I)- and Ru(II)-(pyrazine)-Re(I)-Containing Dyads
- Author
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J. Guerrero, Pedro Aguirre, Guillermo Ferraudi, M. I. Azocar, S. A. Moya, C. Martinez, and L. Mikelsons
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Pyrazine ,Stereochemistry ,Ligand ,Organic Chemistry ,Photodissociation ,Reaction intermediate ,Photochemistry ,Redox ,4,4'-Bipyridine ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Excited state ,Intramolecular force ,Physical and Theoretical Chemistry - Abstract
The photochemical and photophysical properties of the (CO)3(biq)ReI(4,4‘-bipy)RuII(biq)(CO)2Cl2+ and (CO)3(biq)ReI(pz)RuII(biq)(CO)2Cl2+ dyads and the monometallic compounds ReI(biq)(CO)3(4,4‘-bipy)+, ReI(biq)(CO)3(pz)+, and RuII(biq)(CO)2Cl2 have been investigated. Deaerated solutions of these compounds were irradiated at wavelengths between ∼350 and 532 nm. Intraligand, biq-centered, excited states decay by populating Re(I) to biq charge transfer excited states. In the dyads, the Re(I) to biq charge transfer excited states decay by radiative/radiationless relaxation pathways and by forming reaction intermediates. Oxidants and reductants reacted with these intermediates. The Ru(II) to biq charge transfer excited state, 3MLCTRu(II)→biq, could not be observed in a time domain t ≥ 5 ns, and the transfer of energy from the 3MLCTRe(I)→biq to the Ru(II) moiety is an inefficient process. more...
- Published
- 2004
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29. Reactivity of 2,6-diethyl-4,8-dimethyl-1,5-dioxo-s-hydrindacene towards radical, anionic and cationic germylation
- Author
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Pierre Rivière, Fabien Delpech, A. El Kadib, Ivonne Chávez, Heinz Gornitzka, Diana Abril, Pedro Aguirre, Monique Rivière-Baudet, Annie Castel, and Juan M. Manriquez
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Inorganic Chemistry ,Diketone ,Chemistry ,Meso compound ,Spin trap ,Materials Chemistry ,Diastereomer ,Cationic polymerization ,Organic chemistry ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,Hydrindacene ,Medicinal chemistry - Abstract
The synthesis and diastereoisomeric resolution of 2,6-diethyl-4,8-dimethyl-1,5-dioxo-s-hydrindacene allowed the determination of the structure of the meso compound by X-ray diffractometry. The diastereoisomers were inactive towards radical germylation but reacted with acidic hydrogermanes or germylithium yielding α-germylated alcohols. By contrast, they were poorly reactive towards germylamines or SET reactions. This diketone acts as an efficient spin trap in radical hydrogermylation of alkenes. more...
- Published
- 2004
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30. Synthesis of ruthenium complexes with carbonyl and polypyridyl ligands derived from dipyrido[3,2-a:2′,3′-c]phenazine: application to the water gas shift reaction
- Author
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Alvaro J. Pardey, Pedro Aguirre, D. Villagra, I. Azocar-Guzman, R. López, and Sergio A. Moya
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chemistry.chemical_classification ,Ligand ,Phenazine ,Water gas ,chemistry.chemical_element ,General Chemistry ,Photochemistry ,Chemical reaction ,Water-gas shift reaction ,Ruthenium ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Polycyclic compound ,chemistry ,Polymer chemistry - Abstract
The preparation and spectroscopic properties of new dipyrido[3,2-a:2′,3′-c]phenazine ruthenium complexes are described. The complexes show high catalytic activity in the water gas shift reaction in a basic medium under mild conditions (PCO = 0.9 atm at 100 °C). Copyright © 2002 John Wiley & Sons, Ltd. more...
- Published
- 2002
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31. ChemInform Abstract: Methoxycarbonylation of Olefins Catalyzed by Palladium(II) Complexes Containing Naphthyl(diphenyl)phosphine Ligands
- Author
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Sergio A. Moya, Gabriel Abarca, José Parada, Gonzalo Valdebenito, Santiago Zolezzi, and Pedro Aguirre
- Subjects
chemistry.chemical_compound ,Carboxylation ,Chemistry ,chemistry.chemical_element ,General Medicine ,Medicinal chemistry ,Phosphine ,Catalysis ,Palladium ,Styrene - Abstract
The best result is obtained for the conversion of styrene by using the palladium complex PNC.
- Published
- 2014
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32. 2-octyl cyanoacrylate versus reintervention for closure of urethrocutaneous fistulae after urethroplasty for hypospadias: a randomized controlled trial
- Author
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Pedro Aguirre-Ramirez, Sergio Adrián Montero-Cruz, Gabriela Ambriz-González, Mariana Chávez-Tostado, Clotilde Fuentes-Orozco, Alejandro González-Ojeda, Xóchilt Trujillo, Michel Dassaejv Macías-Amezcua, Andrea Socorro Álvarez-Villaseñor, Ana Olivia Cortés-Flores, Francisco Javier León-Frutos, and José Manuel García-de León more...
- Subjects
Relative risk reduction ,Male ,Reoperation ,medicine.medical_specialty ,Urinary Fistula ,2-Octyl cyanoacrylate ,Urethroplasty ,medicine.medical_treatment ,Urology ,Cutaneous Fistula ,law.invention ,chemistry.chemical_compound ,Randomized controlled trial ,Double-Blind Method ,Urethra ,law ,Urethral Diseases ,medicine ,Urethrocutaneous fistula ,Humans ,Cyanoacrylates ,Child ,Surgical repair ,Hypospadias ,business.industry ,Fistula repair ,Infant ,General Medicine ,medicine.disease ,Surgery ,Treatment Outcome ,Reproductive Medicine ,chemistry ,Cyanoacrylate ,Child, Preschool ,Number needed to treat ,Tissue Adhesives ,business ,Research Article - Abstract
Urethrocutaneous fistulae (UCFs) represent one of the most frequent causes of morbidity after urethroplasty. Hypospadias can be repaired using different surgical techniques, but—regardless of technique—the incidence of UCF ranges between 10% and 40%. Surgical repair of UCF remains the treatment of choice, even if some patients need further surgery because of recurrences. Cyanoacrylates have been used as skin suture substitutes, and some evidence suggests a beneficial effect when these adhesives are used as an adjuvant in the management of UCF. Here we describe the results of management of UCF using 2-octyl cyanoacrylate (OCA) compared with surgical repair. A randomized clinical trial conducted from January 2008 to December 2012 included 42 children with UCF complications after urethroplasty for hypospadias. Twenty-one children were assigned to receive OCA as ambulatory patients and 21 were treated surgically. The main outcome variable was closure of the UCF. The estimated costs of both treatments were also calculated, as were absolute risk reduction (ARR), relative risk reduction (RRR) and number needed to treat (NNT) to prevent a surgical intervention. The mean numbers of UCF were 1.3 in the OCA group (n = 28) and 1.1 in the surgical group (n = 25) with no statistically significant difference. The external orifices measured were 2.96 ± 1.0 mm and 3.8 ± 0.89 mm, respectively (NS). Sixty per cent of the UCFs treated with cyanoacrylate were completely closed and 68% of the surgical group healed completely (NS). More than one reoperation to improve complications was needed in the surgical group (3.5 ± 1.2). The clinical significance of the therapeutic usefulness of OCA was demonstrated by an ARR of 0.08, RRR of 0.25 and NNT of 12 to avoid further surgical treatment. The total costs of adhesive applications and reoperations were $US 14,809.00 and $US 158,538.50, respectively. The results showed a similar success rate for both treatments. However, sealant use should be considered before surgical treatment because this is a simple outpatient procedure with a reasonable success rate. ClinicalTrials.gov Identifier: NCT02115191 . Date: April 13, 2014. more...
- Published
- 2014
33. RUTHENIUM (II) COMPLEXES IN CATALYTIC OXIDATION
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Pedro Aguirre, Renato Sariego, and Sergio A. Moya
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Chemistry ,Ligand ,Phenanthroline ,chemistry.chemical_element ,Photochemistry ,Medicinal chemistry ,Ruthenium ,Catalysis ,Metal ,chemistry.chemical_compound ,Bipyridine ,Catalytic oxidation ,visual_art ,Pyridine ,Materials Chemistry ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry - Abstract
Ruthenium (II) complexes of the type RuL(CO)2Cl2, [RuL(CO)2L− 2]2+ and [RuL(CO)2Cl L′]+ [L = bipyridine (bpy), phenanthroline (phen), biquinoline (biq) and L′ = pyridine (py), 4-chloropyridine (Cl-py), 4-methoxypyridine (MeO-py)] were synthesized from [Ru(CO)2Cl2]n and L, to produce the intermediate RuL(CO)2Cl2 followed by hydrolysis and reaction with L′. The catalytic activity of these complexes in epoxidation of olefins with iodosylbenzene under ambient conditions was investigated. A possible mechanism of these reactions, explaining the effects of the ligands on the reaction was explored. At least one carbonyl ligand remained bound to the metal through the reaction. The formation of an oxo intermediate was inferred from spectroscopic detection of bridged oxygen Ru—O—Ru and Ru=O species. more...
- Published
- 2001
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34. Synthesis, structure and catalytic activities for hydrogen transfer reaction of the carbonyl ruthenium(II) complex containing polypyridine and phosphine ligands
- Author
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C. Martinez, H. Le Bozec, Véronique Guerchais, Gabriel Abarca, S. Rodriguez, Matías Vidal, Sergio A. Moya, María Teresa Garland, and Pedro Aguirre
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Substrate (chemistry) ,chemistry.chemical_element ,Transfer hydrogenation ,Photochemistry ,Catalysis ,Ruthenium ,Inorganic Chemistry ,Metal ,chemistry.chemical_compound ,chemistry ,visual_art ,Basic solution ,Polymer chemistry ,Materials Chemistry ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,Triphenylphosphine ,Phosphine - Abstract
The synthesis and characterization of new ruthenium(II) carbonyl complexes containing polypyridine and triphenylphosphine ligands is reported. Crystallographic information obtained for the trans-PPh3-[Ru(biq)(PPh3)2(CO)]Cl2 complex (biq = 2,2’-biquinoline) reveals five-coordination on the metal. The complexes were studied as catalysts in hydrogen transfer reactions in basic solution. Turnover frequencies in the 2250-817 h-1 range were determined in 1 hour of reaction with a substrate/catalysts ratio of 830. more...
- Published
- 2010
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35. A reusable cu-ii based metal-organic framework as a catalyst for the oxidation of olefins
- Author
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Pedro Aguirre, Evgenia Spodine, Verónica Paredes-García, and Patricio Cancino
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Dichloroethane ,Benzaldehyde ,chemistry.chemical_compound ,chemistry ,Inorganic chemistry ,Cyclohexene ,Epoxide ,Metal-organic framework ,Heterogeneous catalysis ,Catalysis ,Nuclear chemistry ,Styrene - Abstract
The metal–organic framework [Cu2(bipy)2(btec)]∞ was used as a heterogeneous catalyst in the liquid phase oxidation of styrene and cyclohexene with tert-butylhydroperoxide (TBHP) as the oxidant either in water–dichloroethane or n-decane medium. Four catalytic systems were tested and compared after 6 hours of reaction. The oxidation of styrene using [Cu2(bipy)2(btec)]∞ showed a competitive conversion, as compared with some CuII heterogeneous catalysts and MOF catalysts. Conversion between 61–45% in dichloroethane:TBHP:water at 75 °C was obtained, using molar ratios of substrate:catalyst from 200 to 2400. When the solvent was replaced by n-decane, the conversion remained similar, that is, between 57–46%, at the same mole ratio range of substrate:catalyst. Styrene oxidation in dichloroethane:TBHP:water [Cu2(bipy)2(btec)]∞ is not selective; the products are benzaldehyde, styrene epoxide and 1-phenylacetaldehyde in 37%, 35% and 29% yields, respectively. The oxidation of cyclohexene showed a conversion of 34–16% under the same experimental conditions in dichloroethane:TBHP:water at 75 °C, with the catalytic reaction presenting a higher selectivity for the formation of 2-cyclohexen-1-one as the product. When n-decane was used, the total conversion in cyclohexene oxidation decreased approximately by 10%, as compared to the dichloroethane:TBHP:water system. The activities reported for the Cu-MOF showed a very high selectivity for the allylic oxidation product. Leaching during the catalytic reaction was found to be negligible, and the structure was maintained during the four catalytic runs, as confirmed by powder X-ray diffraction analysis of the reused catalyst. more...
- Published
- 2014
36. New fluorescent bis-dithienylethene (DTE)-based bipyridines as reverse interrupters: single vs. double photochromism
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Véronique Guerchais, Matías Vidal, Sergio A. Moya, Julien Boixel, Hubert Le Bozec, Pedro Aguirre, Loïc Toupet, Lucie Ordronneau, Vincent Aubert, J. A. Gareth Williams, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Unidad Biosuperficies (CIC biomaGUNE), Centro de Investigación Cooperativa en Biomateriales (CIC biomaGUNE), Facultad de Ciencias Química y Farmacéuticas, Groupe matière condensée et matériaux (GMCM), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry, Durham University, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES) more...
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Quenching (fluorescence) ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Biochemistry ,Acceptor ,Fluorescence ,[PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph] ,0104 chemical sciences ,3. Good health ,Photochromism ,Bipyridine ,chemistry.chemical_compound ,Photostationary state ,Thiophene ,Physical and Theoretical Chemistry ,Solvent effects - Abstract
International audience; The synthesis and characterization of a series of fluorescent bis-dithienylethene (DTE)-based bipyridines, where the donor (D) and acceptor (A) groups are located on the same thiophene ring of the DTE unit, and their zinc(II) and rhenium(I) complexes are reported. Their photochromic properties have been investigated by UV-visible and H-1 NMR spectroscopy. These studies reveal that in non-polar solvents it is possible to modulate the photoreactivity, single vs. double ring-closure, by changing the nature of the donor group. The solvent effect, as well as the influence of the organometallic moieties on the photochromic behavior of these molecules, is also discussed. Finally, upon photoconversion to the photostationary state (PSS), a quenching of fluorescence is observed for the bipyridine ligands, due to disruption of the conjugation upon ring-closing. more...
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- 2013
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37. AMINOCARBONYLATION REACTION USING PALLADIUM COMPLEXES CONTAINING PHOSPHORUS-NITROGEN LIGANDS AS CATALYSTS
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B Apanda, Gonzalo Valdebenito, J Cáceres-Vásquez, Sergio A. Moya, Santiago Zolezzi, and Pedro Aguirre
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inorganic chemicals ,Phosphorus ,Aryl ,chemistry.chemical_element ,Halide ,General Chemistry ,Medicinal chemistry ,Nitrogen ,Catalysis ,chemistry.chemical_compound ,chemistry ,Organic chemistry ,Amination ,Carbon monoxide ,Palladium - Abstract
The catalytic activities of palladium complexes containing phosphorus-nitrogen ligands is reported. The catalysts studied showed high activities in the aminocarbonylation of aryl iodides. The palladium complexes reported activities between 100% and 58% in the aminocarbonylation reaction. The reactions are very selective for the double carbonylative amination of aryl halides. The major product is N,N-diethyl-α-oxo benzeneacetamide (96/4). The reaction was made under mild conditions of temperature and carbon monoxide pressure. more...
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- 2013
38. Complexes with heterocyclic nitrogen ligands—III. Cationic rhodium(I) derivatives and applications in catalysis
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Rebeca Sartori, Sergio A. Moya, Rubén Pastene, Renato Sariego, Hubert Le Bozec, and Pedro Aguirre
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Ligand field theory ,Cationic polymerization ,chemistry.chemical_element ,Photochemistry ,Rhodium ,Catalysis ,Inorganic Chemistry ,Nitrobenzene ,Solvent ,chemistry.chemical_compound ,Aniline ,chemistry ,Polymer chemistry ,Materials Chemistry ,Selective reduction ,Physical and Theoretical Chemistry - Abstract
The preparation and spectroscopic properties of mononuclear cationic complexes of rhodium(I) coordinated to the diolefin 2,5-norbornadiene (NBD) and to the heterocyclic nitrogen ligands 6,7-dihydrodipyrido-[2,3-b:3′,2′-j]-1,10-phenanthroline ( 2-4N ), 7,8-dihydro-6H-cyclohepta-[2,1-b:3,4-b]-di-1,8-naphthyridine ( 3–4N ) and 2,2′-bi-(3-methyl)1,8-naphthyridine ( Me-4N ) are described. The complexes show the characteristic intraligand bands of the ligands and an electronic low energy band insensitive to solvent changes and of low intensity, which may be assigned to a ligand field band. The NMR properties agreed with the IR results showing the equivalence of the two naphthyridine fragments in the complexes. Electrochemically all the complexes display two reductions and one oxidation waves, in the potential region from +1.5 to −2.4 V vs Fc + /Fc. The water gas shift reaction (WGSR) and the selective reduction of nitrobenzene to aniline under WGSR conditions are effectively catalysed by these complexes. more...
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- 1996
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39. Synthesis and characterization of ruthenium (II) carbonyl complexes containing naphthyridine and acetylacetonate ligands and their catalytic activity in the hydrogen transfer reaction
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Hubert Le Bozec, Véronique Guerchais, Juana Gajardo, Loïc Toupet, Juan Carlos Araya, Pedro Aguirre, Sergio A. Moya, Universidad de Santiago de Chile, Universidad de Santiago de Chile [Santiago] (USACH), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Organométalliques: Matériaux et Catalyse, Organométalliques et catalyse : chimie et électrochimie moléculaires (OCCEM), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut des Sciences Chimiques de Rennes (ISCR), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Universidad de Chile, ECOS-CONICYT [CO7E02], CONICYT-Chile, Fondecyt-Chile [1120685], Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences Chimiques de Rennes (ISCR), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS) more...
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Denticity ,Stereochemistry ,chemistry.chemical_element ,[CHIM.INOR]Chemical Sciences/Inorganic chemistry ,010402 general chemistry ,Transfer hydrogenation ,01 natural sciences ,Medicinal chemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,8-Naphthyridine ,Materials Chemistry ,Physical and Theoretical Chemistry ,Carbon monoxide ,Acetophenone ,Acetylacetonate complexes ,010405 organic chemistry ,Hydrogen transfer ,3. Good health ,0104 chemical sciences ,Ruthenium ,chemistry ,Single crystal ,Ruthenium(II) - Abstract
International audience; A series of novel complexes of the Ru(L)(2)(CO)(2) L = 2-(3' methoxyphenyl)-1,8-naphthyridine (complex 1), and type Ru(acac)(2)(L)(CO) with L = 2-(3' methoxyphenyl)-1,8-naphthyridine (complex 2), 2-(2'-bromophenyl)-1,8-naphthyridine (complex 3) and 2-phenyl-1,8-naphthyridine (complex 4) was synthesized and characterized. We found that the complexes 2, 3, and 4 can be directly synthesized from Ru-3(CO)(12). The complex Ru(acac)(2)(L)(CO) L = 2-(3' methoxyphenyl)-1,8-naphthyridine (2) was characterized by X-ray single crystal analysis which confirms the monodentate coordination mode of the 1,8-naphthyridine derivate and the cis arrangement of the acac ligands. Preliminary studies in transfer hydrogenation of acetophenone in the presence of 2-propanol show the good catalytic activity of complex 2 with 92% conversion. (C) 2012 Elsevier B.V. All rights reserved. more...
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- 2013
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40. Ruthenium carbonyl compounds containing polypyridine ligands as catalysts in the reaction of n-benzylideneaniline hydrogenation
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Gabriel Abarca, Sergio A. Moya, C. Negrete-Vergara, Matías Vidal, Pedro Aguirre, and K. Brown
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Phenazine ,Hydrogen transfer ,chemistry.chemical_element ,Homogeneous catalysis ,Photochemistry ,Medicinal chemistry ,Catalysis ,Ruthenium ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Hydrogenation reaction ,Materials Chemistry ,High activity ,Physical and Theoretical Chemistry - Abstract
The synthesis and characterization of ruthenium complexes containing polypyridine ligands: Ru(dppz)(PPh 3 ) 2 Cl 2 , Ru(bpy)(PPh 3 ) 2 Cl 2 , Ru(phen)(PPh 3 ) 2 Cl 2 , Ru(dppz-Cl)(PPh 3 ) 2 Cl 2 , Ru(phen)(CO) 2 Cl 2 , Ru(bpy)(CO) 2 Cl 2 and Ru(dppz)(CO) 2 Cl 2 (where dppz: dipyrido[3,2- a :2′,3′- c ]phenazine, dppz-Cl: 10-chlororodypirido[3,2- a :2′,3′- c ]phenazine, phen: 1,10-phenanthroline and bipy: 2,2′-bipyridine) are reported. The ruthenium complexes show high activity as catalysts in the hydrogenation reaction of N-benzylideneaniline and the hydrogen transfer reaction. The products of the catalysis were obtained with conversions between 21 and 91% after 2 h of reaction. The Ru(phen)(CO) 2 Cl 2 complex was the catalyst that showed the highest conversion (91%) for the hydrogenation of N-benzylideneaniline. The complexes Ru(dppz)(PPh 3 ) 2 Cl 2 , Ru(bpy)(PPh 3 ) 2 Cl 2 and Ru(dppz)(CO) 2 Cl 2 showed 99% conversion in the hydrogen transfer reaction. more...
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- 2012
41. SOL-GEL INCORPORATION OF ORGANOMETALLIC COMPOUNDS INTO SILICA: USEFUL PRECURSORS TO METALLIC NANOSTRUCTURED MATERIALS
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Pedro Aguirre, Carlos Díaz, María Luisa Valenzuela, and Denisse Garrido
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Sol-gel ,Nanostructure ,Nanocomposite ,Materials science ,Nanoparticle ,Nanotechnology ,General Chemistry ,Nanocomposites ,Metal ,Agglomerate ,visual_art ,visual_art.visual_art_medium ,Nanostructured ,Pyrophosphates ,Pyrolysis ,Group 2 organometallic chemistry ,Nuclear chemistry - Abstract
Inclusion of the organometallic MLn = (HOC 5 H 4 NCp 2 TiCl)(PF 6 ) (1), HOC 5 H 4 NW(CO) 5 (2), HOC 5 H 4 NMo(CO) 5 (3), (HOC 6 H 4 CH 2 CNCp 2 TiCl)(PF 6 ) (4), HOC 6 H 4 CH 2 CNW(CO) 5 (5) and HOC 6 H 4 CH 2 CNMo(CO) 5 (6) into amorphous silica using the gelator precursor TEOS and N 3 P 3 {NH(CH 2 ) 3 Si(OEt) 3 } 6 afford the gels (MLn)(SiO 2 ) n . The inorganic-organic hybrid nanocomposites were pyrolyzed under air at 800°C to give nanostructured metal oxides and/or metal pyrophosphates (phosphates) included in the silica matrices. The morphology of the monolithic nanocomposites exhibited a strong dependence on the gel precursor used being mainly laminar for those prepared using N 3 P 3 {NH(CH 2 ) 3 Si(OEt) 3 } as gelator. TEM images show different shape and size such as circular nanoparticles, nanocables and agglomerates in some cases with sizes of 20 nm for the circular nanostructures, and diameter about 25 nm for the nanocables. more...
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- 2012
42. Chiral discrimination in diasteroisomeric systems of cadmium with 1,10-phenanthroline and S-amino acidates
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Antonio Decinti, Pedro Aguirre, and Guillermo Larrazábal
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Chemistry ,Stereochemistry ,Phenanthroline ,Solvation ,Diastereomer ,chemistry.chemical_element ,Zinc ,Ion-association ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,Intramolecular force ,Materials Chemistry ,Physical and Theoretical Chemistry ,Solvent effects ,Diimine - Abstract
Δ,Λ-[Cd(phen) 2 (S-aa)] + NO − 3 diastereomeric systems (where phen = 1,10-phenanthroline and S-aa = S -alaninate, S -serinate, S -threoninate, S -prolinate, S -valinate, S -leucinate and S -phenylalaninate) have been prepared in the form of methanolic solutions and characterized by spectral (UV, CD, ORD) and conductance measurements. The CD spectra of these systems in the β′ band region of the diimine ligand exhibit residuary exciton splittings, whose intensities and sign patterns suggest the following decreasing order of [Λ]/[Δ] diastereoisomeric equilibrium constants: S -prol > S -phenala > S -val > 1 > S -ala > S -leu > S -ser > S -threo. The same order is inferred from the ORD data over the range 400–600 nm. Comparison with the selectivities observed for some zinc analogues and the analysis of molecular models suggest that in the cadmium systems the chiral discriminations are governed mainly by a balancing between intramolecular steric repulsion, differential solvation and discriminating ion association. Solvent effects on the optical activity of some cadmium and zinc systems in methanol/n-propanol and methanol/benzene mixtures have also been studied. The corresponding results are discussed in terms of the contributions of the above discriminating forces. more...
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- 1993
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43. SYNTHESIS, CHARACTERIZATION AND PRELIMINARY CATALYTIC PROPERTIES OF NEW COPPER (I) COMPLEXE [Cu (pyrazolyl)2]X TYPE
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E Santander, C Díaz, Sergio A. Moya, Rubén Pastene, Alvaro J. Pardey, Pablo J. Baricelli, Pedro Aguirre, Ricardo Schmidt, Rebeca Sartori, and Clementina Longo
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Aqueous solution ,Denticity ,WGSR ,Chemistry ,Ligand ,Inorganic chemistry ,chemistry.chemical_element ,Homogeneous catalysis ,General Chemistry ,Electrochemistry ,Copper ,Catalysis ,Metal ,Copper Complexes ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Pyrazolyl Ligand ,Heterocyclic Nitrogen Ligand - Abstract
The preparation of tetracoordinated copper (I) complexes with the pyrazolyl heterocyclic nitrogen ligand is reported. The new complexes of [Cu(pyrazolyl) 2 ]X type with X = chloride, bromine, and iodine were characterized by spectroscopic and electrochemical techniques. The results obtained show that the heterocyclic nitrogen ligand is bonded in a bidentate fashion to form monometallic complexes. Exploratory homogeneous catalysis experiments of the water-gas shift reaction (WGSR) have been accomplished by the use of copper complexes in 80 % aqueous 4-picoline solutions. For such systems, formation of H 2 y CO 2 was observed in the initial gas samples. Keywords: Copper Complexes, Heterocyclic Nitrogen Ligand, Pyrazolyl Ligand, WGSR. e-mail: p.aguirre@ciq.uchile.cl INTROduCTION Copper species are widely present in Nature as mono- or multinuclear metal complexes and play a crucial role in different enzymes and catalytic systems, leading to a currently growing interest in the development of new copper models more...
- Published
- 2010
44. Modulating the luminescence of an iridium(III) complex incorporating a di(2-picolyl)anilino-appended bipyridine ligand with Zn2+ cations
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Muriel Escadeillas, Juan Carlos Araya, Sergio A. Moya, Juana Gajardo, J. A. Gareth Williams, Hubert Le Bozec, Pedro Aguirre, Loïc Toupet, Véronique Guerchais, Facultad de Química y Biología, Universidad de Santiago de Chile [Santiago] (USACH), Facultad de Ciencias Química y Farmacéuticas, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry, Durham University, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), This work was supported by ECOS-CONICYT (Action CO7E02), COST D35 and Region Bretagne (SIE 211-B3-11)., Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) more...
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010405 organic chemistry ,Ligand ,chemistry.chemical_element ,General Chemistry ,[CHIM.CATA]Chemical Sciences/Catalysis ,[CHIM.MATE]Chemical Sciences/Material chemistry ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Catalysis ,3. Good health ,0104 chemical sciences ,Ion ,Bipyridine ,chemistry.chemical_compound ,chemistry ,Excited state ,Materials Chemistry ,Iridium ,Absorption (chemistry) ,Luminescence - Abstract
International audience; A novel iridium complex incorporating a di(2-picolyl)anilino-appended bipyridine ligand was synthesized and its optical properties studied. The presence of Zn2+ ions specifically perturbs the excited state, giving rise to a blue-shifted absorption and emission, and a shorter luminescence lifetime. more...
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- 2010
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45. [Cu(H2btec)(bipy)]infinity: a novel metal organic framework (MOF) as heterogeneous catalyst for the oxidation of olefins
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Evgenia Spodine, Kareen Brown, Verónica Paredes-García, Miguel A. Novak, Santiago Zolezzi, Ricardo Baggio, Pedro Aguirre, and Diego Venegas-Yazigi
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Models, Molecular ,Coordination polymer ,Pyridines ,Inorganic chemistry ,Cyclohexene ,Epoxide ,Alkenes ,Heterogeneous catalysis ,Crystallography, X-Ray ,Catalysis ,Styrene ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,chemistry ,Metal-organic framework ,Selectivity ,Oxidation-Reduction ,Copper - Abstract
A new extended metal-organic framework [Cu(H2btec)(bipy)]infinity. (1) (H4btec= 1,2,4,5-benzenetetracarboxylic acid; bipy = 2,2'-bipyridine) has been hydrothermally synthesized. Violet crystals are formed in a monoclinic system with a space group C2/c; a = 10.1810(18) A, b = 14.4360(18) A, c = 12.894(3) A, beta = 112.94(3) degrees. In the title compound 1 each Cu(II) centre has a distorted square planar environment, completed by two N atoms from one bipy ligand and two O atoms belonging to two dihydrogen benzene-1,2,4,5-tetracarboxylate anions (H2btec2-). The {Cu(bipy)}2+ moieties are bridged by H2btec2- anions to form an infinite one-dimensional coordination polymer with a zig-zag chain structure along the c axis. A double-chain structure is formed by hydrogen bonds between adjacent zig-zag chains. There are also pi-pi stacking interactions between the bipy ligands, with an average distance of 3.62 A resulting in a two-dimensional network structure. Compound 1 was tested as a catalyst for the oxidation of cyclohexene and styrene, with tert-butyl hydroperoxide (TBHP) as oxidant. The catalytic activity (24 h and 75 degrees C) found for [Cu(H2btec)(bipy)]infinity shows a high value for the conversion of cyclohexene (64.5%), and a lower one for styrene (23.7%). High turnover frequency (TOF) values for the epoxide products were observed, indicating that the catalyst synthesized in this work, not only has a high activity and selectivity for epoxidation reactions but is also very efficient. more...
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- 2009
46. ChemInform Abstract: Lewis Super-Acid Catalyzed Cyclizations: A New Route to Fragrance Compounds
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Elisabet Duñach, Lydie Coulombel, Isabelle Favier, Xavier Chaminade, Michel Weïwer, Andreas Heumann, Pedro Aguirre, Fanny Grau, and J. Carles Bayon
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Terpene ,chemistry.chemical_compound ,Cycloisomerization ,chemistry ,Ligand ,Acid catalyzed ,Cyclohexanes ,Substituent ,Organic chemistry ,General Medicine ,Hydroformylation ,Catalysis - Abstract
This review deals with the application of Lewis super acids such as Al(III), In(III), and Sn(IV) triflates and triflimidates as catalysts in the synthesis of fragrance materials. Novel catalytic reactions involving C-C and C-heteroatom bond-forming reactions, as well as cycloisomerization processes are presented. In particular, Sn(IV) and Al(III) triflates were employed as catalysts in the selective cyclization of unsaturated alcohols to cyclic ethers, as well as in the cyclization of unsaturated carboxylic acids to lactones. The addition of thiols and thioacids to non-activated olefins, both in intra- and intermolecular versions, was efficiently catalyzed by In(III) derivatives. Sn(IV) Triflimidates catalyzed the cycloisomerization of highly substituted 1,6-dienes to gem-dimethyl-substituted cyclohexanes bearing an isopropylidene substituent. The hydroformylation of these unsaturated substrates, catalyzed by a Rh(I) complex with a bulky phosphite ligand, selectively afforded the corresponding linear aldehydes. The olfactory evaluation of selected heterocycles, carbocycles, and aldehydes synthesized is also discussed. more...
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- 2008
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47. Lewis super-acid catalyzed cyclizations: a new route to fragrance compounds
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Michel Weïwer, Andreas Heumann, Elisabet Duñach, Lydie Coulombel, Pedro Aguirre, Isabelle Favier, Xavier Chaminade, Fanny Grau, and J. Carles Bayon
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Substituent ,Carboxylic Acids ,Chemistry, Organic ,Bioengineering ,Stereoisomerism ,Biochemistry ,Catalysis ,chemistry.chemical_compound ,Cycloisomerization ,Cyclohexanes ,Organometallic Compounds ,Organic chemistry ,Molecule ,Molecular Biology ,Mesylates ,Molecular Structure ,Chemistry ,Ligand ,Cyclohexanones ,General Chemistry ,General Medicine ,Perfume ,Cyclization ,Alcohols ,Molecular Medicine ,Hydroformylation - Abstract
This review deals with the application of Lewis super acids such as Al(III), In(III), and Sn(IV) triflates and triflimidates as catalysts in the synthesis of fragrance materials. Novel catalytic reactions involving C-C and C-heteroatom bond-forming reactions, as well as cycloisomerization processes are presented. In particular, Sn(IV) and Al(III) triflates were employed as catalysts in the selective cyclization of unsaturated alcohols to cyclic ethers, as well as in the cyclization of unsaturated carboxylic acids to lactones. The addition of thiols and thioacids to non-activated olefins, both in intra- and intermolecular versions, was efficiently catalyzed by In(III) derivatives. Sn(IV) Triflimidates catalyzed the cycloisomerization of highly substituted 1,6-dienes to gem-dimethyl-substituted cyclohexanes bearing an isopropylidene substituent. The hydroformylation of these unsaturated substrates, catalyzed by a Rh(I) complex with a bulky phosphite ligand, selectively afforded the corresponding linear aldehydes. The olfactory evaluation of selected heterocycles, carbocycles, and aldehydes synthesized is also discussed. more...
- Published
- 2008
48. THE STEREOSELECTIVE SYNTHESIS OF THE WERNER COMPLEX WITH SUBSTOICHIOMETRIC SUGARS
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Cristian Garrido, Santiago Zolezzi, José Parada, Carmen P. Vega, Pedro Aguirre, and Guillermo Larrazábal
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Co(III) ,Circular dichroism ,congenital, hereditary, and neonatal diseases and abnormalities ,Chemistry ,Ligand ,Stereochemistry ,nutritional and metabolic diseases ,General Chemistry ,Partial resolution ,circular dichroism ,chemistry.chemical_compound ,Octahedron ,Werner complex ,sugar ,dd* transition dd ,enantioselectivity ,Hexol ,hexol ,Stereoselectivity ,Chirality (chemistry) - Abstract
A tetranuclear complex of Co(III) with hydroxo bridges, so-called “Werner Complex”, was synthesized in the presence of several sugars (1-8) with partial resolution of this complex. The sugars in 10 mol % with respect to Co(III) induce maximum resolution of the Werner complex.Keywords: Werner complex, hexol, sugar, Co(III), circular dichroism, dd* transition dd*, enantioselectivity.e-mail: jparada@ciq.uchile.cl. INTRODUCTION The present work is an example of induction of chirality from a chiral “sugar” ligand to the inorganic Werner complex (Fig.1). The Werner complex is a classic example of a chiral compound that does not contain carbon and was one of the first examples of chirality in octahedral complexes. 1, 2 Fig. 1. Structure of ∆-[Co[(OH) 2 Co(NH 3 ) 4 ] 3 ] 6+ .In an earlier publication 2 we showed that sugars induce stereoselective synthesis of the Werner complex, also known as “hexol”. We have now extended the work by synthesizing tetranuclear complex of Co(III) in presence of several sugars (Scheme 1, 1-8). more...
- Published
- 2008
49. Synthesis and characterization of new complexes of the type [Ru(CO)2Cl2(2-phely-1,8-naphthyridine-kN) (2-phenyl-1,8-naphthyridine-kN')] Preliminary applications in homogeneous catalysis
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Alvaro J. Pardey, Sergio A. Moya, Pedro Aguirre, Juan Carlos Araya, Véronique Guerchais, Hubert Le Bozec, J. Carles Bayón, Juana Gajardo, Jaime J. Cornejo, Universidad de Santiago de Chile, Universidad de Santiago de Chile [Santiago] (USACH), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Universidad Central de Venezuela (UCV), Facultad de Quimica [Santiago], Pontificia Universidad Católica de Chile (UC), Universidad de Chile, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) more...
- Subjects
010405 organic chemistry ,Stereochemistry ,Chemistry ,chemistry.chemical_element ,Homogeneous catalysis ,General Chemistry ,[CHIM.CATA]Chemical Sciences/Catalysis ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Ruthenium ,Inorganic Chemistry ,NMR spectra database ,Solvent ,chemistry.chemical_compound ,Polymer chemistry ,Dimethylformamide ,Chelation ,Hydroformylation ,ComputingMilieux_MISCELLANEOUS - Abstract
Novel ruthenium (II) complexes were prepared containing 2-phenyl-1,8-naphthyridine derivatives. The coordination modes of these ligands were modified by addition of coordinating solvents such as water into the ethanolic reaction media. Under these conditions 1,8-naphthyridine (napy) moieties act as monodentade ligands forming unusual [Ru(CO)2Cl2(η1-2-phenyl-1,8-naphthyridine-kN)(η1-2-phenyl-1,8-naphthyridine-kN′)] complexes. The reaction was reproducible when different 2-phenyl-1,8-naphthyridine derivatives were used. On the other hand, when dry ethanol was used as the solvent we obtained complexes with napy moieties acting as a chelating ligand. The structures proposed for these complexes were supported by NMR spectra, and the presence of two ligands in the [Ru(CO)2Cl2(η1-2-phenyl-1,8-naphthyridine-kN)(η1-2-phenyl-1,8-naphthyridine-kN′)] type complexes was confirmed using elemental analysis. All complexes were tested as catalysts in the hydroformylation of styrene showing moderate activity in N,N′-dimethylformamide. Copyright © 2008 John Wiley & Sons, Ltd. more...
- Published
- 2008
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50. Design and spectroscopic study of new ruthenium(ii) complexes containing ligands derived from terpyridine and dipyrido[3,2-a : 2 ,3 -c]phenazine: {ru(4 -rph-tpy)[dppz(cooh)]cl}pf6 with r=no2, br, cl
- Author
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M. Yañez, R. López, Sergio A. Moya, Cesar Zúñiga, Pedro Aguirre, and J. C. Bayón
- Subjects
Absorption spectroscopy ,Stereochemistry ,Ligand ,Phenazine ,Spectrophotometric titration ,chemistry.chemical_element ,General Chemistry ,Electrochemistry ,Medicinal chemistry ,Chemical synthesis ,Ruthenium ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Terpyridine - Abstract
A series of polypyridine ruthenium complexes of the general formula {Ru(Rph-tpy)[dppz(COOH)]Cl} PF6 with R = Br (1), Cl (2), NO2 (3) where Rph-tpy is 4′-(4-Rphenyl-2,2′:6′,2″-terpyridine and dppz(COOH) is dipyrido[3,2-a:2′,3′-c]phenazine-2-carboxylic acid were prepared and characterized. These complexes display intense metal-to-ligand charge-transfer (MLCT) bands centered about 500 nm. The effect of pH on the absorption spectra of these complexes consisting of protonatable ligands has been investigated in water solution by spectrophotometric titration. The electrochemistry shows oxidation potentials for the Ru(II)–Ru(III) couple at +0.881 (1), +0.907 (2) and +0.447 V (3), respectively. Copyright © 2006 John Wiley & Sons, Ltd. more...
- Published
- 2006
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