Bernardo Monteiro, Leonor Maria, Adelaide Cruz, José M. Carretas, Joaquim Marçalo, João Paulo Leal,
Ionic liquids (ILs) have been revealed as promising solvents, namelly for the selective extraction of metals from aqueous solutions. ILs extractive properties can be trimmed but to do that in a programmed and educated way it is necessary to know their basic properties. The range of temperature in which they can be used as solvents as well as their specific heat, necessary to perform thermodynamic calculations with them, are fundamental properties needed to achieve this desideratum. Thus, the goal ...
Tópico(s): Chemistry and Chemical Engineering
2019 - Elsevier BV | Thermochimica Acta
Leonor Maria, Adelaide Cruz, José M. Carretas, Bernardo Monteiro, Catarina Galinha, Susana Sousa Gomes, M. Fátima Araújo, de Paiva, Joaquim Marçalo, João Paulo Leal,
Four ionic liquids, tetraoctylammonium oleate – [N8888][OL], 1-butyl-3-methylimidazolium-di(2-ethylhexyl)-oxamate – [C4mim][DEHOX], tetraoctylammonium dioctyl-diglycolamate – [N8888][DODGA] and tetraoctylammonium di(2-ethylhexyl)-oxamate – [N8888][DEHOX]), were studied concerning the extraction and selective separation of lanthanides from aqueous solutions. The influence of several factors (pH, time of contact between phases, ionic strength, ionic liquid to metal ratio) were analysed. Also, back-extraction and ...
Tópico(s): Radioactive element chemistry and processing
2019 - Elsevier BV | Separation and Purification Technology
Ana F. Lucena, José M. Carretas, Joaquim Marçalo, Maria C. Michelini, Yu Gong, John K. Gibson,
Gas-phase complexes of uranyl(V) ligated to anions X(-) (X = F, Cl, Br, I, OH, NO3, ClO4, HCO2, CH3CO2, CF3CO2, CH3COS, NCS, N3), [UO2X2](-), were produced by electrospray ionization and reacted with O2 in a quadrupole ion trap mass spectrometer to form uranyl(VI) anionic complexes, [UO2X2(O2)](-), comprising a superoxo ligand. The comparative rates for the oxidation reactions were measured, ranging from relatively fast [UO2(OH)2](-) to slow [UO2I2](-). The reaction rates of [UO2X2](-) ions containing polyatomic ...
Tópico(s): Nuclear Materials and Properties
2015 - American Chemical Society | The Journal of Physical Chemistry A
Ana F. Lucena, Célia Lourenço, Maria C. Michelini, Philip X. Rutkowski, José M. Carretas, Nicole Zorz, Laurence Berthon, Ana Dias, M. Conceição Oliveira, John K. Gibson, Joaquim Marçalo,
Gas-phase hydrolysis of lanthanide/actinide MO 3 (NO 3 ) 3 − ions relates to the stabilities of the M IV oxidation states, which correlate with IV/III solution reduction potentials and 4th ionization energies.
Tópico(s): Catalytic Processes in Materials Science
2015 - Royal Society of Chemistry | Physical Chemistry Chemical Physics
Elsa Mora, Leonor Maria, Biplab Biswas, Clément Camp, Isabel C. Santos, Jacques Pécaut, Adelaide Cruz, José M. Carretas, Joaquim Marçalo, Marinella Mazzanti,
The homoleptic compounds [U(salan-R2)2] (R = Me (1), tBu (2)) were prepared in high yield by salt-metathesis reactions between UI4(L)2 (L = Et2O, PhCN) and 2 equiv of [K2(salan-R2)] in THF. In contrast, the reaction of the tetradentate ligands salan-R2 with UI3(THF)4 leads to disproportionation of the metal and to mixtures of U(IV) [U(salan-R2)2] and [U(salan-R2)I2] complexes, depending on the ligand to M ratio. The reaction of K2salan-Me2 ligand with U(IV) iodide and chloride salts always leads to mixtures ...
Tópico(s): Lanthanide and Transition Metal Complexes
2012 - American Chemical Society | Organometallics
Sónia Barroso, Jinlan Cui, José M. Carretas, Adelaide Cruz, Isabel C. Santos, M. Teresa Duarte, João P. Telo, N. Marques, Ana M. Martins,
Reactions of titanium and yttrium trichlorides with 1 equiv of the sodium or potassium salts of the diamine bis(phenolate) H2tBu2O2NN′ (Me2NCH2CH2-(CH2-2-HO-3,5-C6H2tBu2)2) led to formation of [TiCl(tBu2O2NN′)(L)] (L = THF, 1; py, 2) and [YCl(tBu2O2NN′)(DME)], 3. Reactions of 1 or 3 with MCH2-(2-NMe2)C6H4 and with M[2-(CH2NMe2)C6H4] (M = Li, K) led to [Ti(tBu2O2NN′)(κ2-(CH2C6H4NMe2))], 5, [Y(tBu2O2NN′)(κ2-(CH2C6H4NMe2))], 6, and [Y(tBu2O2NN′)(κ2-(C6H4CH2NMe2))], 7. [Y(tBu2O2NN′)N(SiMe3)2], 4, was obtained from ...
Tópico(s): Synthesis and characterization of novel inorganic/organometallic compounds
2009 - American Chemical Society | Organometallics
José M. Carretas, Joaquim Marçalo, António Pires de Matos,
Tópico(s): Chemical Thermodynamics and Molecular Structure
2004 - Elsevier BV | International Journal of Mass Spectrometry
Nadine Marchandé, Sylvie Breton, Serge Géribaldi, José M. Carretas, António Pires de Matos, Joaquim Marçalo,
Abstract Gas phase reactions of the rare earth metal cations Y + and Ln + (Ln = La–Lu, except Pm) with trimethylorthoformate and of Y + and Lu + with triethyl and tripropyl orthoformates were studied by Fourier transform ion cyclotron resonance mass spectrometry. The results obtained were compared with previous observations made with the remaining rare earth cation Sc + and confirmed that, in the gas phase, trialkylorthoformates can be good alkoxy group suppliers, leading to dialkoxymetal ions, which subsequently ...
Tópico(s): Crystallography and molecular interactions
2000 - Elsevier BV | International Journal of Mass Spectrometry
José M. Carretas, António Pires de Matos, Joaquim Marçalo, M. Pissavini, Michèle Decouzon, Serge Géribaldi,
The gas-phase reactions of Sc+, Y+, and Ln+ (Ln=La-Lu, except Pm) ions with phenol were studied by Fourier transform ion cyclotron resonance mass spectrometry. All the ions except Yb+ were observed to react with the organic substrate, activating O-H, C-O, and/or C-H bonds, with formation of MO+, MOH+, and/or MOC6H4+ ions as primary products. The product distributions and the reaction efficiencies obtained showed the existence of important differences in the relative reactivity of the rare earth metal ...
Tópico(s): Chemical Reaction Mechanisms
1998 - American Chemical Society | Journal of the American Society for Mass Spectrometry
José M. Carretas, António Pires de Matos,
Abstract The synthesis of metal alkoxides and aryloxides of lanthanides by the metal vapour technique has been investigated. The reactions of Ce, Sm, Eu and Yb with MeOH, EtOH and Pr i OH were studied. The compound Sm[OC 6 H 3 (Bu t ) 2 ] 3 was obtained from the reaction of samarium with 2,6-di-t-butylphenol.
Tópico(s): Chemical Thermodynamics and Molecular Structure
1992 - Elsevier BV | Materials Chemistry and Physics
José M. Carretas, Joaquim Branco de Oliveira, Joaquim Marçalo, Ângela Domingos, António Pires de Matos,
Tópico(s): Inorganic Chemistry and Materials
2003 - Elsevier BV | Polyhedron
Produção Nacional
Revisado por pares
José M. Carretas, Joaquim Branco de Oliveira, Joaquim Marçalo, P.C. Isolani, Ângela Domingos, António Pires de Matos,
The reactions of europium and ytterbium in liquid ammonia with a solution of 1-naphthol in tetrahydrofuran provide a convenient route to lanthanide aryloxides. The polymetallic lanthanide complexes [Eu4(μ-OC10H7)6(OC10H7)2(THF)10].2THF 1 and [Yb(μ-OC10H7)(OC10H7)2(THF)(MeCN)]2.2MeCN 2 were synthesized and characterized by X-ray diffraction studies.
Tópico(s): Lanthanide and Transition Metal Complexes
2001 - Elsevier BV | Journal of Alloys and Compounds
José M. Carretas, Joaquim Branco de Oliveira, Joaquim Marçalo, João C. Waerenborgh, N. Marques, António Pires de Matos,
Tópico(s): Advanced Materials Characterization Techniques
1998 - Elsevier BV | Journal of Alloys and Compounds
Produção Nacional
Revisado por pares
Bernardo Monteiro, Nuno A. G. Bandeira, Célia Lourenço, Ana F. Lucena, José M. Carretas, John K. Gibson, Joaquim Marçalo,
The diverse gas-phase reactivity of [LnO 2 (NO 3 ) 2 ] − complexes with water (Ln = Ce, Pr, Nd), examined in a quadrupole ion trap and complemented by ab initio computations, illuminates the chemical stability of Pr in the unusual +5 oxidation state.
Tópico(s): Analytical chemistry methods development
2019 - Royal Society of Chemistry | Chemical Communications
Ana F. Lucena, José M. Carretas, Joaquim Marçalo, María del Carmen Michelini, Philip X. Rutkowski, John K. Gibson,
Complementary experimental and computational methods for evaluating relative charge densities of metal cations in gas-phase clusters are presented. Collision-induced dissociation (CID) and/or density functional theory computations were performed on anion clusters of composition MM'A(m+n+1)(-), where the two metal ions have formal charge states M(m+) and M'(n+) and A is an anion, NO3(-), Cl(-), or F(-) in this work. Results for alkaline earth and lanthanide metal ions reveal that cluster CID generally ...
Tópico(s): Catalytic Processes in Materials Science
2014 - American Chemical Society | The Journal of Physical Chemistry A
N. Marques, Joaquim Marçalo, Teresa Almeida, José M. Carretas, António Pires de Matos, Kenneth W. Bagnall, Josef Takats,
Tópico(s): Thermal and Kinetic Analysis
1987 - Elsevier BV | Inorganica Chimica Acta
Cláudia C. L. Pereira, José M. Carretas, Bernardo Monteiro, João Paulo Leal,
Searching in the Web of Knowledge for "ionic liquids" AND "luminescence" AND "lanthanide", around 260 entries can be found, of which a considerable number refer solely or primarily to europium (90%, ~234). Europium has been deemed the best lanthanide for luminescent applications, mainly due to its efficiency in sensitization, longest decay times, and the ability to use its luminescence spectra to probe the coordination geometry around the metal. The remaining lanthanides can also be of crucial importance ...
Tópico(s): Radioactive element chemistry and processing
2021 - Multidisciplinary Digital Publishing Institute | Molecules
José M. Carretas, Jinlan Cui, Isabel C. Santos, Adelaide Cruz, Leonor Maria, Joaquim Marçalo,
Reactions of UI3(THF)4, UCl4 and ThCl4 with 1 equiv. of tris(3,5-dimethylpyrazolyl)methane (Tpm∗) in THF led to the formation of the complexes [U(Tpm∗)I3(THF)] (1), [U(Tpm∗)Cl4] (2) and [Th(Tpm∗)Cl4] (3) in good yields. The NMR spectra indicated symmetrical structures in solution, with equivalent pyrazolyl groups of the Tpm∗ ligand. The X-ray crystal structures of the three complexes were determined and in all cases the metallic centre is seven-coordinated, presenting distorted capped octahedral coordination ...
Tópico(s): Crystal structures of chemical compounds
2011 - Elsevier BV | Inorganica Chimica Acta
Phuong D. Dau, José M. Carretas, Joaquim Marçalo, Wayne W. Lukens, John K. Gibson,
The gas-phase complexes AnO2(CH3CO2)2(-) are actinyl(V) cores, An(V)O2(+) (An = U, Np, Pu), coordinated by two acetate anion ligands. Whereas the addition of O2 to U(V)O2(CH3CO2)2(-) exothermically produces the superoxide complex U(VI)O2(O2)(CH3CO2)2(-), this oxidation does not occur for Np(V)O2(CH3CO2)2(-) or Pu(V)O2(CH3CO2)2(-) because of the higher reduction potentials for Np(V) and Pu(V). It is demonstrated that NO2 is a more effective electron-withdrawing oxidant than O2, with the result that ...
Tópico(s): Lanthanide and Transition Metal Complexes
2015 - American Chemical Society | Inorganic Chemistry
Tópico(s): Early Modern Spanish Literature
2014 - | Revista portuguesa de musicologia
Francisco Varona-Cordero, Francisco José Gutiérrez Mendieta, María Esther Castillo,
During an annual cycle (2002–2003), spatio-temporal differences and/or similarities in phytoplankton communities and their relationship with physical and chemical characteristics were determined in two coastal lagoons on the Mexican South Pacific coast: Chantuto-Panzacola (CHP) and Carretas-Pereyra (CP), Chiapas. Phytoplankton assemblages, characteristic of the two main seasons (dry and wet), were identified using principal component analysis (PCA), while canonical correspondence analysis (CCA) was used ...
Tópico(s): Marine Toxins and Detection Methods
2010 - Oxford University Press | Journal of Plankton Research
José M. Carretas, Sónia Barroso, Jinlan Cui, Adelaide Cruz, Isabel C. Santos, Ana M. Martins,
Samarium complexes supported by the diamine bis(phenol) proligand H2(tBu2O2NN′) = Me2N(CH2)2N{CH2-(2-OH-3,5-tBu2-C6H2)2} were prepared and structurally characterized. [Sm(tBu2O2NN′)]2(μ-Cl)2 (1) was obtained from reaction of SmCl3 with K2(tBu2O2NN′) in THF, DME or pyridine. The reaction of 1 with LiNEt2 gave a zwitterionic bimetallic complex of Sm and Li, [Sm(tBu2O2NN′)2Li] (2) that formed upon ligand redistribution and did not allow the isolation of the expected diethylamido derivative. Analogously treatment ...
Tópico(s): Synthesis and characterization of novel inorganic/organometallic compounds
2013 - Elsevier BV | Inorganica Chimica Acta
José M. Carretas, L.M. Ferreira, Pedro M.P. Santos, Susana Sousa Gomes, M. Fátima Araújo, Leonor Maria, João Paulo Leal,
Lanthanides are critical elements, and their recovery from wastewater increases the availability of these elements and reduces their impacts on the environment. In this study, tentative approaches to extract lanthanides from low-concentration aqueous solutions were investigated. PVDF membranes soaked with different active compounds or synthesized chitosan-based membranes containing these active compounds were used. The membranes were immersed in 10-4 M of aqueous solutions of selected lanthanides, ...
Tópico(s): Radioactive element chemistry and processing
2023 - Multidisciplinary Digital Publishing Institute | Membranes
Jéssica D. S. Vicente, Domingas C. Miguel, Afonso M. P. Gonçalves, Diogo M. Cabrita, José M. Carretas, Bruno J. C. Vieira, João C. Waerenborgh, Dulce Belo, A.P. Gonçalves, João Paulo Leal,
Ionic liquids are critical reagents for science and technical processes nowadays. Metals are the most used reagents in the industry. It is crucial to have a deeper understanding of how ionic liquids and metals could interact. In this article the interaction of those two families of compounds is accessed. The dissolution (reaction) of metals with ionic liquids is studied, namely the influence of temperature, redox potential, and availability of an oxidant in the process. The final state achieved by ...
Tópico(s): Electrochemical Analysis and Applications
2021 - Multidisciplinary Digital Publishing Institute | Sustainable Chemistry
José M. Carretas, Joaquim Branco de Oliveira, J MARCEDILALO, Nuno Valente, J CARLOSWAERENBORGH, Angelita Alves de Carvalho, N. Marques, Matheus David Inocente Domingos, A PIRESDEMATOS,
The reactions of samarium, europium and ytterbium metals with the potential bidentate ligand 2-methoxyphenol were investigated. The europium and ytterbium aryloxides were synthesized by dissolution of the metals in liquid ammonia, whereas the samarium aryloxide was synthesized by metal vapour synthesis (MVS). The compounds obtained were formulated as Ln(OC6H4OMe)3, Ln=Sm, Yb and Eu(OC6H4OMe)2. Recrystallization of Yb(OC6H4OMe)3 in the presence of THF/pentane resulted in the crystallographically characterized ...
Tópico(s): Coordination Chemistry and Organometallics
2004 - Elsevier BV | Journal of Alloys and Compounds
S. Abisset, F. Maury, Luc Pelletier, José M. Carretas, A PIRESDEMATOS,
Vanadium carbide coatings V8C7 have been deposited on steel substrates by MOCVD using bis(arene)vanadiums as precursors at temperatures lower than 550 °C. Addition of C6Cl6 in the gas phase allows to reduce the carbon content of the films to 13 at. %. These metal coatings exhibit the features of a metastable carbon-rich solid solution. Carbonitride V(C,N) and nitride δ-VN layers with only 5 at. % carbon have been deposited in the presence of NH3. These reactive gas phases allow to grow almost all the ...
Tópico(s): Diamond and Carbon-based Materials Research
1998 - International Information and Engineering Technology Association | Annales de Chimie Science des Matériaux
Filipe M.J. Figueiredo, José M. Carretas, João Paulo Leal, José P. Sardinha,
Abstract The measurement of metals in solution is usually performed using inductive coupled plasma hyphenated techniques or atomic absorption. Although very sensitive and accurate, these analytical techniques are quite expensive and do not allow field measurements. The present work takes advantage of energy-dispersive X-ray fluorescence (ED-XRF) ease-of-use features to determine the concentration of rare earth elements (Y, Pr, Nd, Eu) and others (S, Fe, Ni, Cu, Zn) in aqueous solutions, after appropriate ...
Tópico(s): Analytical chemistry methods development
2024 - Springer Nature | Journal of Analytical Science & Technology
Sandrina Oliveira, Nuno A. G. Bandeira, João Paulo Leal, Leonor Maria, José M. Carretas, Bernardo Monteiro, Joaquim Marçalo,
The gas-phase reactions of noble gas (Ng) cations, namely Kr+ and Xe+, with SF6 were investigated experimentally by Fourier transform ion cyclotron resonance mass spectrometry and computationally using RI-MP2 and BCCD(T) methods. The study revealed a new interaction between Kr+ and neutral SF6 that gave rise to a new cationic, weakly bound complex of Kr, [KrSF5]+, although the major reaction channel was dissociative electron transfer to yield SF5+ and {Kr, F}. Experimental studies examined the formation ...
Tópico(s): Fluorine in Organic Chemistry
2022 - Royal Society of Chemistry | Physical Chemistry Chemical Physics
Tópico(s): History, Culture, and Society
2016 - University of Costa Rica | Cuadernos Inter c a mbio sobre Centroamérica y el Caribe
Tópico(s): Archaeology and Cultural Heritage
2011 - University of Costa Rica | Anuario de Estudios Centroamericanos