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António Pires de Matos

António Pires de Matos
New University of Lisbon (a) ; (b) Portuguese Nuclear Institute /IST Universidade de Lisboa · (a) Research Unit "Glass and Ceramics for the Arts; (b) CTN

PhD University of Cambridge 1970

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124
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Publications

Publications (124)
Article
In this work polyelectrolyte multilayers (PEMs) produced through the layer-by-layer (LbL) method were used for the in situ synthesis of Au and Ag metal nanoparticles on the surface of float glass in order to colour it. The samples were characterized by UV-Vis absorption spectroscopy, Scanning Electron Microscopy (SEM), Rutherford Backscattering Spe...
Conference Paper
Lanthanide ions display intense photoluminescence under UV light. When incorporated in glass they are used not only in technological applications, but in artworks as well. Luminescent glasses with compositions similar to those used in utilitarian, decorative and architectural applications, doped with small amounts of several lanthanides oxides, nam...
Article
Due to its non-crystalline, amorphous structure, glass is particularly susceptible to radiation-induced coloration/discoloration. Oxide glasses reveal a variety of colors depending upon their composition when exposed to high energy radiations such as gamma and X-rays, and the colors induced have been explained in terms of the formation of color cen...
Article
Metal nanoparticles inside glass present useful properties to photonic applications and have been object of several research works. In particular, laser beams have shown their potential in its creation and both ultraviolet beams with nanosecond pulses, and near-infrared beams with femtosecond pulses, have been used. In this paper, the authors add n...
Article
Local decolorizing of gamma-ray irradiated silicate glasses has been studied under thermal annealing by a laser beam. The influence of the beam's exposure time was studied, showing that an increase of the glass temperature on the irradiated areas can locally induce complete decolorizing (bleaching) of glass. In this work, the heat conduction differ...
Conference Paper
Full-text available
Contemporary stained glass models were developed in this work using colourless float glass with luminescent glass threads or flecks, and painted with luminescent enamels. CO2 laser engraving was also used to explore the image effects on float glass coated with layers of luminescent glass.
Article
In this work, coloured glasses were produced based on the synthesis of gold and silver nanoparticles by the sol–gel process having in mind their application in art works. Gold and silver were used separately or as a mixture by varying the mole fractions in order to get a range of colours from yellow to red. The gold and silver nanoparticles were pr...
Article
For the first time copper nanoparticles were formed inside Cu ion-doped glass after infrared irradiation by a nanosecond laser and sucessive annealing at 700 °C for 1 h. The surface plasmon resonance was observed in the absorption spectra of copper nanoparticles. Their spectral position is in good agreement with the values predicted by Mie theory f...
Article
The hydrogenation of propionitrile on copper-lanthanide oxide catalysts (2Cu·CeO2 and 4Cu·Ln2O3 (Ln=La, Pr, Nd)) was studied in the gas phase. The activity of the catalysts varies with the lanthanide in the order 2Cu·CeO2>4Cu·Pr2O3>4Cu·La2O3≥4Cu·Nd2O3, while the activation energies varies in the opposite order, except for 2Cu·CeO2. The main product...
Article
Laser ablation of solid UO(3) or (NH(4))(2)U(2)O(7) yielded in the gas phase molecular uranium oxide anions with compositions ranging from [UO(n)](-) (n = 2-4) to [U(14)O(n)](-) (n = 32-35), as detected by Fourier transform ion cyclotron resonance mass spectrometry. The cluster series [U(x)O(3x)](-) for x < or = 6 and various [U(x)O(3x-y)](-), in w...
Article
The gas-phase reactivity of doubly charged lanthanide cations, Ln2+ (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), with alkanes (methane, ethane, propane, n-butane) and alkenes (ethene, propene, 1-butene) was studied by Fourier transform ion cyclotron resonance mass spectrometry. The reaction products consisted of different combinat...
Article
Gold ruby glass was made by irradiating a soda-lime-silicate glass with ca. 0.2 weight % of gold with gamma rays and further heating instead of using a reducing agent such as stannous oxide. Different colours were obtained by controlling the temperature and heating times. A comparison of this process to develop ruby glass with the conventional ones...
Article
Full-text available
In this study the application of luminescent glasses under UV light in artworks is explored. Several lanthanide oxides were used in the glass composition to obtain different colours. A brief comparison with the conventional glass artwork using neon is made. Future conservation was taken into account and the compatibility studies of mixtures of diff...
Article
The presence of uranium glass objects in museum and private collections has raised radiation protection concerns resulting from possible exposure to ionizing radiation emitted by this type of object. Fourteen glass objects with different uranium contents were studied. Dose rates (β + γ radiation) were measured with a beta/gamma probe at several dis...
Article
Fourier transform ion cyclotron resonance mass spectrometry was employed to study the products and kinetics of gas-phase reactions of Cm (+) and Cm (2+); parallel studies were carried out with La (+/2+), Gd (+/2+) and Lu (+/2+). Reactions with oxygen-donor molecules provided estimates for the bond dissociation energies, D[M (+)-O] (M = Cm, Gd, Lu)....
Article
The study of isoprene (2-methyl-1,3-butadiene) gas phase hydrogenation on ThNi2 and UNi2 was undertaken and the effect of the 5f element on nickel catalytic behavior investigated. At nearly steady state, the reaction products were isopentane and isopentenes (2-methyl-2-butene, 2-methyl-1-butene and 3-methyl-1-butene). The total selectivity to isope...
Article
The reduction of the heterobimetallic copper–lanthanide oxides 2CuO·CeO2 and 3CuO·Ln2CuO4 (Ln=La, Pr, Nd) was studied by H2-TG/DTA and H2-TPR. All systems exhibit two main reduction steps accompanied by mass losses in the temperature range 20–1000°C. The first step was attributed to CuO reduction, whereas the second step is due either to copper red...
Article
Full-text available
Fundamental aspects of the chemical and physical properties of atomic and molecular actinide ions and neutrals are being examined by Fourier transform ion cyclotron resonance mass spectrometry (FTICR/MS). To date, gas-phase reactivity studies of bare and ligated An+ and An2+ ions, where An = Th, Pa, U, Np, Pu, Am, and Cm, with oxidants and with hyd...
Article
The hydrogenation of propionitrile over binary copper−lanthanide intermetallic compounds (LnCu2, Ln = La, Ce, Pr, Nd) was studied in the gas phase. The results show that the reaction main product is the primary amine, the n-propylamine. To our knowledge, it is the first time that such behavior is reported for copper catalysts.
Article
Activation of small (C1−C4) alkanes and alkenes by bare and oxo-ligated actinide cations (Th+ through Cm+) has been systematically examined using Fourier transform ion cyclotron resonance mass spectrometry. The reduced reactivities of Pu+, Am+, and Cm+ correlate with the energies for electronic excitation to a 5fn-26d7s configuration, which indicat...
Article
Recent theoretical calculations have shown that Ir should behave as a chemical analogue to N, with the result that IrUO{sup +}, like known NUO{sup +}, is predicted to be a stable species isoelectronic with UO{sup 2+}, the uranyl dication. The target heterometallic analogue to uranyl has now been prepared by direct laser desorption/ionization of a U...
Article
Oxidation reactions of bare and ligated, monopositive, and dipositive Pa ions in the gas phase were studied by Fourier transform ion cyclotron resonance mass spectrometry. Seven oxidants were employed, ranging from the thermodynamically robust N(2)O to the relatively weak CH(2)O-all oxidized Pa(+) to PaO(+) and PaO(+) to PaO(2)(+). On the basis of...
Article
The ionization energy of NpO 2 was determined by the electron-transfer bracketing technique employing Fourier transform ion cyclotron resonance mass spectrometry. Under thermoneutral conditions the NpO2+ ion was found to abstract an electron from N, N, N', N'-tetramethyl-1,4-phenylenediamine (IE = 6.20 ± 0.05 eV) but not from N, N-dimethyl-1,4-phen...
Article
Reactions of atomic and ligated dipositive actinide ions, An2+, AnO2+, AnOH2+, and AnO2(2+) (An = Th, U, Np, Pu, Am) were systematically studied by Fourier transform ion cyclotron resonance mass spectrometry. Kinetics were measured for reactions with the oxidants, N2O, C2H4O (ethylene oxide), H2O, O2, CO2, NO, and CH2O. Each of the five An2+ ions r...
Article
In our laboratories we have been studying the synthesis and reactivity of binary actinide and lanthanide intermetallic compounds. In this work, the air-oxidation of ThCu2 and AnNi2 (An = Th, U) was followed by thermogravimetry (TG) and the products were characterized by X-ray powder diffraction (XRD). The heterobimetallic oxides obtained are descri...
Article
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...
Article
The gas-phase reactions of the lanthanide series cations Ln+ (Ln=La-Lu, except Pm) with methanol, ethanol, and 2-propanol were studied by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The majority of the lanthanide cations react exothermically with the alcohols, with formation of LnO+ and LnOH+ ions as main primary product...
Article
Gas-phase ion chemistry experiments with americium using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) were performed for the first time. Reactions of Am+ and AmO+ with the oxidants N2O, C2H4O (ethylene oxide), H2O, O2, CO2, and NO have been studied. Am+ formed AmO+ with all the reagents except NO, while AmO+ only reacted w...
Article
The elemental composition (K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Ba, Nd and Pb) of modern coloured glasses was obtained by energy-dispersive x-ray fluorescence (EDXRF) spectrometry. This non-destructive technique is frequently used in the analysis of historical glass objects. Two reference glasses were also measured to assess the overa...
Article
The reactions of europium and ytterbium with 2,6-di-tert-butylphenol were studied by the metal vapour synthesis technique and by dissolution in liquid ammonia. The lanthanide complexes [Eu(OC6H3But2-2,6)2(THF)3]·0.75C7H81 and [Yb(OC6H3But2-2,6)2(NCMe)4] 2 were synthesized and characterized by X-ray diffraction studies.
Article
The first gas-phase ion chemistry studies of the transuranium actinides Np and Pu by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) have been performed. Reactions of An+ and AnO+ (An = Th, U, Np, and Pu) with N2O, C2H4O (ethylene oxide), H2O, O2, CO2, NO, and CH2O have been studied, with a focus on the oxidation of transuran...
Article
Gas-phase ion chemistry studies of lanthanide organometallic species have been performed, seeking differences and similarities with equivalent condensed-phase systems. Several examples of the work done are given, namely investigations of lanthanide–arene complexes, lanthanocenes, lanthanide alkoxides and aryloxides, and complexes with lanthanide–tr...
Article
The gas-phase reactions of lanthanide (Ln+=La+–Lu+, except Pm+) and actinide (An+=Th+, U+) cations with iron pentacarbonyl, Fe(CO)5, and with ferrocene, Fe(C5H5)2, were studied by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). In the case of Fe(CO)5, the observed primary products were of the type MFe(CO)x+ (M=La, Ce, Pr, N...
Article
Isoprene hydrogenation on LnNi (Ln=Pr, Gd, Tm) rare earth intermetallic compounds has been studied. The effect of rare earth elements on nickel catalytic behaviour was investigated. The results at steady state indicate that the compounds are all more active than pure nickel. The main reaction products are 2M2B (2-methyl-2-butene) and 2M1B (2-methyl...
Article
In this work we report the synthesis and characterization of europium(II) hydrotris(pyrazol-1-yl)borate complexes, Eu(HBPz3)2L2 (L=bis(pentamethylene)urea, diphenylphosphineamide, 2-azacyclononanone, 2-azacycloheptanone). The characterization of the complexes was accomplished by Fourier transform ion cyclotron resonance mass spectrometry using elec...
Article
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.
Data
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Article
Tetra(tetraphenylimidophosphinato)thorium, Th(tpip)4 (1), was obtained from Th(NO3)4·4H2O and Ktpip in aqueous medium. The analogous uranium compound, U(tpip)4 (2), has been prepared by reacting UCl4 with Ktpip in a 1:4 stoichiometric ratio, either in THF or in aqueous solution. X-ray diffraction analysis showed that compounds 1 and 2 were isostruc...
Article
Europium(II) hydrotris(pyrazol-1-yl)borate complexes, Eu(HBpz3)2L2 (L=diphenylsulfoxide (1) and bis(pentamethylene)urea (2)), have been synthesized. Characterization of 1 and 2 by infrared absorption spectroscopy points to coordination of the neutral ligands through the sulfoxide and carbonyl oxygens, respectively. This was corroborated by X-ray di...
Article
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 ca...
Article
Reaction of UCl4 with one equivalent of the thallium salt of [HB(3-Mspz)3]− (=TpMs, Ms = mesityl) afforded UCl3TpMs*1, due to isomerization of the TpMs ligand to give [HB(3-Mspz)2(5-Mspz)]− (=TpMs*). Crystals of UCl3TpMs2 were obtained fortuitously in one particular instance, but a real synthetic route to this compound was not achieved. 1 adds THF...
Article
Uranium tetrachloride reacts with two equivalents of K[B(pz)4] in THF affording [UCl2{B(pz)4}2] (1) in 75% yield. Complex 1 is monomeric and crystallizes in the monoclinic space group C2/c with cell parameters a=13.700(6), b=12.759(2), c=17.513(8) Å, β=101.37(2)°, V=3001(2) Å3, Z=4. Derivatives [UCl(OR){B(pz)4}2] (R=C2H5 (2), tBu (3), C6H4-o-OMe (4...
Article
Reactions of PuCl3 and LnCl3 (Ln=Pr, Nd ) with the stoichiometric amount of KTpMe2 (TpMe2=HB (3,5-Me2pz)3) yielded the dimeric [MCl (μ-Cl)TpMe2 (Me2pzH)]2 compounds (M=Pu (1), Pr (2), Nd (3)). The analogous reaction with YbCl3 afforded the monomeric YbCl2TpMe2 (THF) complex (4). The crystal and molecular structures of 2 and 4 have been assessed by...
Article
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 pr...
Article
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...
Article
Direct 'dissolution' of metallic europium and ytterbium in alcohols, without the use of a catalyst, was studied. In this work we report the reactions with methanol, ethanol and isopropanol. The Mossbauer spectra of the europium compounds indicated that the element in the obtained products is in the oxidation state II, whereas for the ytterbium comp...
Article
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...
Article
Gas-phase reactions of M+, M2+, MO+ (M = Th and U), and UO2+ with several arenes (benzene, naphthalene, toluene, mesitylene, hexamethylbenzene, and 1,3,5-tri-tert-butylbenzene) have been studied by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). For M+ ions C−H and/or C−C bond activation was observed in the primary reaction...
Article
The gas-phase reactivity of lanthanide (Ln+ = La+−Lu+), group 2 (Ca+, Sr+, and Ba+), and group 3 (Sc+ and Y+) cations, and of their corresponding monoxide ions MO+, with pentamethylcyclopentadiene (C5Me5H) was studied by Fourier transform ion cyclotron resonance mass spectrometry. The reactivity of Eu+, Tm+, Yb+, and the alkaline earth metal ions w...
Article
The reaction of [UCl2HB(pz)32] (1) with lithium alkyls LiR (R = Me, CH2SiMe3, C6H4-o-CH2NMe2) in the 1:1 or 1:2 molar ratio affords the compounds [UCIRHB(pz)32] (pz = C3H3N2, R = Me (2), CH2SiMe3 (3), C6H4-o-CH2NMe2 (4)) and [UR2HB(pz)32] (R = Me (5), CH2SiMe3 (6)) respectively in 60–80% yield. Complex 2 can also be obtained (60% yield) by redistri...
Article
The gas phase chemistry of bis(pentamethylcyclopentadienyl)samarium, (C5Me5)2Sm, was studied by Fourier transform ion cyclotron resonance mass spectrometry (FTICR/MS). Positive electron impact (EI) spectra showed the formation of (C5Me5)2Sm+, (C5Me5)Sm+, and Sm+. All three ions reacted with (C5Me5)2Sm by charge transfer, as verified by double-reson...
Article
The reaction [LnI2(THF)x] (Ln - Sm, Eu, Yb) with 2 equiv. of K[B(pz)4] (pz = pyrazolyl) in THF resulted in the formation of [Ln{B(pz)4}2(THF)2] complexes. The molecular structure of [Eu{B(pz)4}2(THF)2] has been determined by single-crystal X-ray diffraction analysis. The [Sm{B(pz)4}2(THF)2] and [Yb{B(pz)4}2(THF)2] complexes are fluxional in solutio...
Article
The complex YbCp2·3TMU (TMU = 1,1,3,3-tetramethylurea) has been synthesized by addition of (CH3)2NCON(CH3)2 to YbCp2·2THF, obtained by reduction of YbCp2Cl·THF with sodium naphthalenide. The characterization was done by metal analysis and IR and 1H nuclear magnetic resonance spectroscopies. Orange-reddish crystals of YbCp2·2TMU, were obtained by sl...
Article
The rhenium(VII) compound [ReO3{B(pz)(4))}] (1) is easily reduced by triphenylphosphine in tetrahydrofuran providing, in 60% yield, a very reactive oxo complex of Re that, on the basis of its reactivity, we tentatively formulate as ''[ReO(mu-O){B(pz)(4)}](2)'' (2). This air-stable compound is insoluble in tetrahydrofuran and water and slightly solu...
Article
The air-oxidation of the intermetallic compounds LaCuâ, CeCuâ, PrCuâ, and NdCuâ was followed by thermogravimetry. The mass uptake occurred over a wide range of temperature (423-1100 K), leading to two stoichiometrics according to the lanthanide; CeCuâOâ and LnCuâO{sub 3.5} (Ln = La, Pr, Nd). The characterization by powder X-ray diffraction, scannin...
Article
The rhenium(V) ethylene glycolate complex [ReO(OCH2CH2O){B(pz)(4)}] (1) has been prepared in one step synthesis by reacting [ReOCl3(SMe(2))(OPPh(3))] or [ReOCl3(PPh(3))2(]) with ethylene glycol and K[B(pz)4(]) (50-60% isolated yield). Complex 1 reacts with 2-mercaptoethanol and with 1,2-ethanedithiol in the presence of triethylamine providing respe...
Article
Gas-phase reactions of Sc+, Y+, and lanthanide metal ions (M(+)) with 1,3,5-tri-tert-butylbenzene (L) have been investigated at 10(-6) to 10(-7) Torr by means of FT/ICR mass spectrometry in the first systematic study in which all of the lanthanide series elements (except for Pm+) are included. For Sm+, Eu+, Tm+, and Yb+, sandwich complex ions, ML(2...
Article
The tetravalent uranium hydrocarbyl compounds UCl2[CH(SiMe3)2]L* (L* = HB(3,5-Me2-pz)3) and UCl3-x(CH2SiMe3)(x)L* (x = 1-3) have been prepared by salt metathesis from UCl3L* (THF) and the appropriate lithium alkyls. The reactivity of the carbyls UCl2[CH(SiMe3)2]L* (1) and UCl2(CH2SiMe3)L* (2) toward ketones has been studied. Compound 2 reacts with...
Article
During the reaction of a uranium pellet with freshly sublimed elemental iodine in THF, ring opening of the THF was observed and a U-IV species was obtained. Further reaction of the solution with Na[HB(3,5Me(2)pz)(3)] in THF at room temperature gave, after recrystallization, a green crystalline solid 2 formulated as [UI2{O(CH2)(4)I}{HB(3,5-Me(2)pz)(...
Article
The 1 : 1 adducts of UCl3[HB(3,5-Me2Pz)3] with thf, pyridine (NC5H5), acetonitrile (MeCN), benzonitrile (PhCN), cyclohexylisocyanide (C6H12NC), triethylphosphate (tep), tributylphosphate (tbp) and triphenylphosphine oxide (tppo) have been prepared and characterized. The structure of the tep compound was determined by single-crystal X-ray analysis....
Article
The Re(VII)complex (Bpz4)ReO3 (1) has been isolated in the reaction of Re2O7 with KBpz4 in THF and characterized. The solid-state structure of this complex has been determined by X-ray crystallography. The complex is monomeric with an approximately octahedral arrangement of ligands around the rhenium and crystallizes in the monoclinic space group C...