María González-Béjar

María González-Béjar
University of Valencia | UV · Instituto de Ciencia Molecular (ICMol)/ Departamento de Química Orgánica

About

81
Publications
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1,654
Citations
Additional affiliations
September 2011 - present
Universitat de València
June 2007 - August 2011
Université d'Ottawa
Position
  • University of Ottawa

Publications

Publications (81)
Article
Near-infrared optical imaging offers some advantages over conventional imaging, such as deeper tissue penetration, low or no autofluorescence, and reduced tissue scattering. Lanthanide-doped nanoparticles (LnNPs) have become a trend in the field of photoactive nanomaterials for optical imaging due to their unique optical features and because they c...
Article
Full-text available
Nanoparticles for medical use should be non-cytotoxic and free of bacterial contamination. Upconversion nanoparticles (UCNPs) coated with cucurbit[7]uril (CB[7]) made by combining UCNPs free of oleic acid, here termed bare UCNPs (UCn), and CB[7], i.e., UC@CB[7] nanohybrids, could be used as photoactive inorganic-organic hybrid scaffolds for biologi...
Article
Correction for ‘NIR laser scanning microscopy for photophysical characterization of upconversion nanoparticles and nanohybrids’ by Juan Ferrera-González et al. , Nanoscale , 2021, 13 , 10067–10080, DOI: 10.1039/D1NR00389E.
Article
Full-text available
This review explores the current state‐of‐the‐art for functional photoactive hybrids containing inorganic nanoparticles (magnetic and metal) and conjugated organic porous polymers (CPPs). Albeit new in the field, with the first hybrid material of this kind reported in 2012, those materials have gained increasing interest in applications such as sen...
Article
Photophysical characterization of upconversion nanoparticles (UCNPs) and nanohybrids (UCNHs) is more challenging than that of down-conversion nanomaterials. Moreover, it is still difficult to gain knowledge about the homogeneity of the sample and colocalization of emissive chromophores and nanoparticles in nanohybrids. Near infrared laser scanning...
Article
Full-text available
Sensitized emission of lead halide perovskite nanoparticles (LHPNPs) can be achieved by near‐infrared (NIR) excitation of nearby lanthanide‐doped upconversion nanoparticles (UCNPs) by using a low‐cost diode laser. Here, the first preparation of linear assemblies of core and core–shell NPs, as well as linear coassemblies of LHPNPs and UCNPs, within...
Chapter
Upconversion nanoparticles (UCNPs) and dyes are combined to make nanohybrid systems, which take advantage of the synergic relationship between lanthanide (Ln)-based UCNPs and dyes. Ln-UCNPs are inorganic nanophosphors which absorb NIR light and emit narrow emission bands in the UV-NIR region with long luminescence lifetimes. These unique properties...
Article
Chemical/biological sensing by means of luminescence still requires improvement of signal contrast and depth of sample imaging. Though there is a considerable number of emissive molecular and quantum dot probes, most of them absorb in the UV–vis range and emit in the visible and exhibit emission lifetime in the nanoscale. Optical bioimaging in the...
Article
Full-text available
The stability of organic cappings on hexagonal NaYF 4 :Ln ³⁺ upconversion nanoparticles (UCNPs) is crucial for their luminescence efficiency in aqueous solutions. The capping removal quickens as the acidity of the medium increases. We demonstrate here that polysulfonates, namely poly(2-acrylamido-2-methyl-1-propanesulfonate) (PAMPS) and poly(sodium...
Conference Paper
Full-text available
Se ha diseñado una página web para involucrar a los estudiantes de máster en el aprendizaje colaborativo y cooperativo, mejorando así su aprendizaje y comprensión de los temas y conceptos relevantes. Para ello, los temas incluidos en la asignatura Técnicas Avanzadas en Química que forma parte del Máster en Química Sostenible de la Universidad de Va...
Article
Full-text available
Up to now, most strategies to build efficient 800-nm-light responsive upconversion nanoparticles (UCNPs) have included onion-layered structures, in which Nd3+ is confined within the inorganic crystal structure of at least one layer. We report here an easy room-temperature modular preparation of core-shell UCNPs consisting of NaYF4:Yb,Er(Tm)/NaYF4 (...
Article
Theranostic upconversion nanoparticles (UCNPs) are ideal candidates for personalized medicine. We present a smart, easy-to-prepare nanohybrid (NH) suitable for NIR-theragnosis and imaging tracking without triggering therapy simultaneously. The photophysical features of each component have been carefully selected in order to maximize the capabilitie...
Article
Full-text available
A new family of cobalt complexes with the general formula [CoII(OTf)2(Y,XPyMetacn)] (1R, Y,XPyMetacn= 1-[(4-X-3,5-Y-2-pyridyl)methyl]-4,7-dimethyl-1,4,7-triazacyclononane, X= CN (1CN), CO2Et (1CO2Et), Cl (1Cl), H (1H), NMe2 (1NMe2)) where Y= H, and X= OMe when Y= Me (1DMM)) is reported. We found that the electronic tuning of the Y,XPyMetacn ligand...
Article
The photopysical behaviour of 7-mercapto-4-methylcoumarin (C-SH) and derivatives has been studied in different solvents. In contrast to 7-hydroxy-4-methylcoumarin, C-SH shows poor emission, but high fluorescence when the thiol is alkylated. The origin and character of the lowest singlet states are discussed, specifically proposing that the thione-l...
Article
Heterogeneous catalysts that can absorb light in the solar range are ideal for green photocatalysis. Recently, attention has been directed towards the generation of novel solar-light photocatalysts, in particular metal-free polymers. We demonstrate here that a metal-free, non-conjugated, anthraquinone-based copolymer (COP) with strong absorption in...
Article
CH3NH3PbBr3 perovskite nanoparticles (PAD) are prepared with a photoluminescence quantum yield of ≈100% in air atmosphere by using the quasi-spherical shaped 2-adamantylammonium bromide (ADBr) as the only capping ligand. The photostability under wet conditions of this kind of nanoparticles is enhanced by using cucurbit[7]uril-adamantylammonium (AD@...
Article
Upconversion-perovskite nanohybrids are prepared by assembling CH3NH3PbBr3 perovskite nanoparticles (PK) with naked NaYF4:Yb3+,Tm3+ nanoparticles (UCn) via an innovative strategy consisting of using cucurbit[7]uril (CB[7]) to anchor the perovskite nanoparticles firmly and closely to the upconversion nanoparticles, thus leading to UCn@PKCB nanohybri...
Article
Full-text available
Nanomaterials are proving useful for regenerative medicine in combination with stem cell therapy. Nanoparticles (NPs) can be administrated and targeted to desired tissues or organs and subsequently be used in non-invasive real-time visualization and tracking of cells by means of different imaging techniques, can act as therapeutic agent nanocarrier...
Article
Water-dispersible upconversion nanoparticles (β-NaYF4:Yb(3+),Er(3+), UCNP) coated with a thin shell of a biocompatible copolymer comprising 2-hydroxyethylmethacrylate (HEMA) and 2-acrylamido-2-methyl-1-propanesulphonsulphonic acid (AMPS), which we will term COP, have been prepared by multidentate grafting. This capping is remarkably resistant to st...
Article
Reduction of Au3+ in the presence of just adenosine 5′-monophosphate (AMP) and a zwitterionic organic chemical buffering agent, specifically 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), combined with light exposure, gives rise to luminescent, water-soluble Au+ nanoclusters (Au+ NCs). The photoluminescence of these NCs is considerably...
Article
Full-text available
Steady-state and time-resolved emission studies on nanohybrids consisting of NaYF4:Yb,Er and a diiodo-substituted Bodipy (UCNP-IBDP) show that the Yb(3+) metastable state, formed after absorption of a near-infrared (NIR) photon, can decay via two competitive energy transfer processes: sensitization of IBDP after absorption of a second NIR photon an...
Article
The most frequently used strategy for sensing is based on the emission variation of a photoactive system and it can be classified as chemical or physical depending on its response to either a chemical or a physical stimulus. There are a large number of luminescent nanomaterials that respond to chemical species, but comparatively, with the exception...
Conference Paper
Full-text available
Rare earth nanocrystalline phosphors exhibit unique upconversion luminescence with sharp bandsand long emission lifetimes. Upconversion luminescence is a process in which two or more low energy photons (near-infrared light) are converted into higher energy photons (visible light). Near infrared light allows deeper tissue penetration and suppresses...
Article
A generalization of the molar-ratio method is applied to the determination of the stoichiometry and apparent binding constant of metal nanoparticle-organic capping complexes (MmLx) using voltammetric data for the oxygen reduction reaction (ORR) in air-saturated aqueous phosphate buffer solutions. The method is applied to the formation of binary nan...
Article
Full-text available
Spontaneous adsorption of cucurbit[n]uril CB[n] (n = 6, 7, and 8) on the surface of naked upconversion nanoparticles (UCNPs), in particular, NaYF4:Er(3+)(2%),Yb(3+)(18%) gave rise to UCNP@CB[n] exclusion complexes. These complexes proved to be highly stable as well as highly emissive under near-infrared excitation. By using two tricyclic basic dyes...
Chapter
Metallic nanoparticles are considered a new class of heterogeneous photocatalysts due to their ability to absorb solar light and convert it into chemical energy. Here, we focus on the use of silver nanoparticles in light driven catalytic processes. This chapter will start with a brief introduction to the currently available nanocomposites that cont...
Article
Upconversion nanoparticles (β-NaYF4:Er3+, Yb3+, UCNPs) were capped with a thin polymer shell by replacing the oleate ligand of hydrophobic UCNPs by multidentate thiolate-grafting of P(MEO2MA-co-SEMA) copolymers. The presence of the 2-(2-methoxyethoxy)ethyl side chains of MEO2MA extending out of the nanohybrid made them water-dispersible. The UCNP@P...
Article
Gold nanoparticles capped with cucurbituril[7] have been prepared in the absence of metallic cations and organic ligands. Remarkably, these nanohybrids encapsulate dissolved oxygen and are highly active in its electrochemical reduction. The effect of the presence of sodium and ammonium salts on this catalysed process is also analysed.
Conference Paper
Full-text available
Curcubit[7]urils-capped NaYF 4 : Yb 3+ (18%), Er 3+ (2%) nanoparticles. Surface modification of nanoparticle with cyclic molecules wich have molecular recognition abilities holds great importance in the construction of functional nanodevices. Curcubit[n]urils (CB[n]) are a family of water soluble macrocycles of glycoluril units which have increased...
Article
Texture and phase recognition analysis (TPRA) based on electron nanodiffraction technique is used to characterize the geometry of up-conversion nanocrystals (UCNCs) synthesized by the common thermal-decomposition protocol in the presence of a stoichiometric amount of NH4F. Here, we confirmed experimentally that despite the apparently different shap...
Article
Full-text available
We report the preparation of water-dispersible, ca. 30 nm-sized nanohybrids containing NaYF4:Er3+, Yb3+ up-conversion nanoparticles (UCNPs), capped with a polyethylene glycol (PEG) derivative and highly loaded with a singlet oxygen photosensitizer, specifically a diiodo-substituted Bodipy (IBDP). The photosensitizer, bearing a carboxylic group, was...
Data
Full-text available
We report the preparation of water-dispersible, ca. 30 nm-sized nanohybrids containing NaYF4:Er3+, Yb3+ up-conversion nanoparticles (UCNPs), capped with a polyethylene glycol (PEG) derivative and highly loaded with a singlet oxygen photosensitizer, specifically a diiodo-substituted Bodipy (IBDP). The photosensitizer, bearing a carboxylic group, was...
Article
The preparation of [FeIV(O)(MePy2tacn)]2+ (2, MePy2tacn = N-methyl-N,N-bis(2-picolyl)-1,4,7-triazacyclononane) by reaction of [FeII(MePy2tacn)(solvent)]2+ (1) and PhIO in CH3CN and its full characterization are described. This compound can also be prepared photochemically from its iron(II) precursor by irradiation at 447 nm in the presence of catal...
Article
Full-text available
Amine-capped, lipophilic CdSe/ZnS quantum dots can be transferred in the presence of a switchable surfactant, specifically N′-oleyl-N,N-dimethylacetamidine, from an organic phase to water and then reverted to the organic phase simply by the addition/removal of carbon dioxide. The strategy is based on interdigitation of the surfactant between the no...
Article
The catalytic epoxidation of cis-stilbene using cumene as a solvent in the presence of supported gold nanoparticles (AuNP) yields a mixture of cis and trans-stilbene oxides. EPR and product distribution studies support a new mechanistic proposal where oxygen centred radicals activate the AuNP surface and form active surface oxygen species responsib...
Article
A simple, fast, and highly selective and sensitive colorimetric assay to detect nanomolar levels of spermine in human urine (healthy donors, cancer patients) is reported. This assay is based on the absence of a competitive organic capping on the gold nanoparticles together with the high affinity of the amine groups of the analyte for the nanopartic...
Article
Ketorolac shows reduced photohemolytic activity and low phototoxicity against human skin fibroblasts when compared to ketoprofen. The low decarboxylation quantum yield together with the efficient non-radiative deactivation of the triplet and singlet excited states of ketorolac are believed to be responsible for this behaviour.
Article
Silver ions (Ag+) can be quantified in situ in the presence of AgNPs by using a colorimetric sensing probe (3,3´,5,5´-tetramethylbenzidine). Interestingly, it also enables detection of the Ag+ adsorbed on the AgNP surface. This is relevant to design new methods to make AgNPs while ensuring the total reduction of Ag+.
Article
A simple and straightforward method for the orthogonal functionalisation of upconverting NaYF4 nanocrystals (UCNCs)-doped withYb(3+) and Er(3+) -based on N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysuccinimide (EDC/NHS) selective reactions between two dyes and two different reactive groups present at the periphery of the upconverting na...
Article
Ablated, "pseudo-naked" gold nanoparticles (AuNPs) catalyze the cis-trans isomerization of substituted azobenzenes. para-Substitution was found to affect the rate of isomerization, suggesting the participation of AuNP-mediated electron transfer in the isomerization mechanism.
Data
Due to the considerable industrial implications, an in-depth study of cumene peroxidation using supported gold and silver nanoparticles was carried out to gain more insight into the mechanism of this reaction. Supported gold nanoparticles were found to efficiently catalyze the decomposition of cumene hydroperoxide with a selectivity of 25% at 80 de...
Article
Surface plasmon excitation of supported gold nanoparticles in the presence of H2O2 leads to selective oxidation of sec-phenethyl and benzyl alcohols to the carbonyl products acetophenone and benzaldehyde, respectively, in the absence of additional solvents. Light-emitting diodes are compared with microwave irradiation as excitation sources. Hydrota...
Article
Full-text available
Gold nanoparticles capped with oleylamine can be effectively transferred from an organic solvent to water in the presence of an acetamidine surfactant by CO2 bubbling and then effectively reverted back to the organic phase by N2 bubbling.
Article
Surface plasmon excitation of gold nanoparticles on ZnO in the presence of an aldehyde, an amine and phenylacetylene led to rapid and selective formation of propargylamines with good yields (50-95%) at room temperature. Plasmon mediated catalysis is the best available route for this ternary coupling.
Article
We report a novel nanosecond laser ablation synthesis for spherical gold nanoparticles as small as 4 nm in only 5 s (532 nm, 0.66 J/cm(2)), where the desired protecting agent can be selected in a protocol that avoids repeated sample irradiation and undesired exposure of the capping agent during ablation. This method takes advantage of the recently...
Article
Spherical 3.5 nm diameter silver nanoparticles (AgNP) stabilized in type I collagen (AgNP@collagen) were prepared in minutes (5-15 min) at room temperature by a photochemical method initiated by UVA irradiation of a water-soluble non-toxic benzoin. This biocomposite was examined to evaluate its biocompatibility and its anti-bacterial properties and...
Article
Methylene blue shows an isotope dependent triplet lifetime that is 50% longer in D(2)O compared with H(2)O as a result of electronic-to-vibrational relaxation. The effect is enhanced when the dye is bound to curcubit[7]uril due to a combination of restricted mobility and a unfavorable vibrational coupling.
Article
There is no doubt that light is the greenest reagent for catalytic processes. In this chapter the use of organic molecules, organometallic complexes, semiconductors and metallic nanoparticles in catalytic processes driven by light is discussed. Basic photochemistry concepts are highlighted in each example. Light-driven processes are used in many ap...
Article
Gold nanoparticles (AuNP) supported on hydrotalcite, γ-Al2O3 and TiO2 P25 have been prepared photochemically under mild conditions using ketyl radicals as the primary reducing agent; these nanocomposites were prepared directly in the solid phase. Such dry, solventless methods are attractive from an environmental perspective. The composite materials...
Article
Surface plasmon excitation of aqueous colloidal gold nanoparticles with visible light in the presence of H2O2 led to rapid and selective oxidation of sec-phenethyl and benzyl alcohols to acetophenone and benzaldehyde, respectively. Laser drop, light emitting diode, and microwave irradiation have been used as energy sources. Interestingly, sec-phene...
Article
The ketone-photoinduced formation of Au, Ag, and Cu nanoparticles from their corresponding ions in solution has been carried out using benzoin photoinitiators. Ketones are good photosensitizers for nanoparticle synthesis not because of the energy they can absorb or deliver, but rather because of the reducing free radicals they can generate. Efficie...
Article
The influence of the phenolic hydroxyl group of ortho-hydroxy atorvastatin metabolite (Ato-OH) on the photochemistry of atorvastatin (Ato) has been evaluated by steady and time-resolved experiments. Direct excitation of Ato and Ato-OH led to phenanthrene-like intermediate formation, being ∼30% for Ato-OH less efficient than that for its parent comp...
Article
The dependence of the interaction between human serum albumin (HSA) and two epimeric bioconjugates, which contain (S)- or (R)-naproxen (NPX) bound to a cyclopentapeptide with an arginine-glycine-aspartate sequence (cRGD), on the absolute configuration of the naproxen moiety has been studied using several complementary experiments, such as direct ph...
Article
The understanding of the interaction of CdSe/ZnS semiconductor quantum dots (QD) with their chemical environment is fundamental, yet far from being fully understood. p-Methylphenyldiazonium tetrafluoroborate has been used to get some insight into the effect of diazonium salts on the spectroscopy of QD. Our study reveals that the surface of CdSe/ZnS...
Article
The photobehavior of merocyanine 540 (MC) was studied in homogeneous media (ethanol, buffer and glycerol), and in microheterogenous systems (Triton X-100 micelles and in the presence of human serum albumin) using stationary and time-resolved techniques. Merocyanine 540 in aqueous solution mostly forms aggregates, which in the presence of Triton X-1...
Article
Aqueous gold nanoparticles (AuNPs) cause a large increase in the yield of methylene blue triplets ((3)MB*) obtained upon 650 nm laser excitation as a result of surface plasmon field interactions that can be described as transmitter-receiver antenna effects. Two distinct (3)MB* populations are observed; a fast decaying one (tau(T) approximately 25 n...
Article
Cucurbiturils (CBs) of the appropriate size (CB[7] and CB[8]) form strong guest-host complexes in phosphate buffer solution (PBS) with acridine orange (AO) and pyronine Y (PYY) with 1 : 1 and 2 : 1 stoichiometries for CB[7] and CB[8] complexes, respectively. Binding constants in the range 0.87-1.60 x 10(6) M(-1) and 5.2-6.3 x 10(13) M(-2) were dete...
Article
The effect of methylene blue (MB) encapsulation in cucurbit[7]uril (CB[7]) on triplet excited-state behavior and singlet oxygen (1O2) generation has been studied by using laser flash photolysis (LFP) and time-resolved near-IR luminescence spectroscopy. The lifetime of the triplet excited state of MB is longer in the CB[7] cavity (140 micros for MB-...
Article
Full-text available
Interaction of 7-mercapto-4-methylcoumarin with the surface of core-shell CdSe-ZnS quantum dots leads to characteristic absorption and emission bands that are excellent reporters for thiol interactions at the nanoparticle surface.
Article
Efficient intramolecular fluorescence quenching in pyrene-benzoylthiophene systems leads to formation of exciplexes. These species interact with 1,3-cyclohexadiene (or styrenes), leading to reactive excited triplexes. The overall process affords [2+2] cross-cycloadducts with an average yield of 57%.
Article
[reaction: see text] Naphthalene photo-catalyzes formation of cyclohexadiene-indole cycloadducts in a wavelength-dependent process. Steady-state irradiation and time-resol