Open Access
Diverse methods with stereoselective induction in the asymmetric Biginelli reaction
(MDPI Publishing, 2024-08-15) Díaz Fernández, Marcos; Algarra González, Manuel; Calvo Losada, Saturnino; Quirante, José Joaquín; Sarabia, Francisco; Pino-González, María Soledad; Institute for Advanced Materials and Mathematics - INAMAT2
The relevance of the asymmetric Biginelli reaction (ABR) has been increased in this century, due to the pharmacological application of its products. This review focuses predominantly on articles published in the period from 2015 to 2024 on asymmetric synthetic advances in the formation of dihydropyrimidinones (DHPMs), dihydropyrimidinethiones (DHPMTs), and related compounds. The relevant bibliography on general processes in the Biginelli reaction and some methods of separation of isomers have also been referenced.
Embargo
Testing of black-carrots-derived fluorescence imaging and anti-metastatic potential
(Elsevier, 2024) Algarra González, Manuel; Carrillo, Celia; Nesic, Maja D.; Filipovic Trickovic, Jelena; Zakula, Jelena; Koricanac, Lela; Jiménez-Jiménez, José; Rodríguez-Castellón, Enrique; Bandosz, Teresa J.; Petkovic, Marijana; Soto, Juan; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
This paper explains the basis for the excitation energy-independent fluorescence emission of biomass-derived carbon dots (CDs) and shows that these CDs have excellent anti-melanoma and anti-metastatic potential. Additionally, we demonstrate that the black carrots´-derived CDs can be exploited as cell cycle-sensing agents, because of the interaction with chromatin material. Besides their optical properties, fluorescent CDs have gained increased attention for image-guided cancer treatment due to their water solubility, environmental friendliness, affordability, ease of synthesis, and primary biocompatibility. CDs have excellent photostability, determined by their precursors and synthesis pathways. In this study, CDs with chemically homogenous surface functional groups were made using a hydrothermal technique from black carrot extract, an anthocyanin-rich substance derived from biomass. The anti-cancer and anti-metastatic properties of black carrot-derived CDs can be attributed to flavylium cations on the surface, spherical forms, and high water dispersibility. Most importantly, these CDs demonstrate a stable emission at a single wavelength, 612 nm, independent of the excitation energy, which we have explained theoretically for the first time.
Open Access
Green chitosan: thiourea dioxide cleaning gel for manganese stains on granite and glass substrates
(Springer Nature, 2021) Campos, Bruno; Marco, Alexandra; Cadeco, Guilhermina; Freire-Lista, David M.; Silvestre-Albero, Joaquín; Algarra González, Manuel; Vieira, Eduarda; Pintado, Manuela; Moreira, Patricia; Ciencias; Zientziak
The cleaning or removal of manganese stains on Cultural Heritage has not been much tested or successful so far. The aim of this article was to assess a new green cleaning gel for Mn-rich black-blue stains on different substrates. The black-blue stains were characterized at optical and chemical level through colour-related data, optical microscope, FTIR, XRF and XPS. Mn-stained granite found on historical churches at Vila Real (North of Portugal) and glass jars of Leclanché cells, belonging to the ISEP's Museum (Portugal) collection, were the ideal case studies to test the efficiency of chitosan: thiourea dioxide (TD) cleaning gel. TD proved to be the best candidate to reduce insoluble manganese oxides, over Hydroxylamine Hydrochloride and Hydroxymethanesulfinic Acid. Cleaning assays performed on stained granite samples collected at a historical quarry and in situ application on stained granite churches allowed removal of the stains to a satisfactory level. Similar results were obtained on stained glass jars.
Open Access
Cellulose polymers with β-amino ester pendant group: design, synthesis, molecular docking and application in adsorption of toxic metals from wastewater
(BioMed Central, 2022) Nairat, Noor; Hamed, Othman; Berisha, Avni; Jodeh, Shehdeh; Algarra González, Manuel; Azzaoui, Khalil; Dagdag, Omar; Samhan, Subhi; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
Background: Cellulose polymers with multidentate chelating functionalities that have high eficiency for toxic metal ions present in water were designed, synthesized, and analyzed. The synthesis was carried out by reacting microcrystalline cellulose extracted from the solid waste of the olive industry with tert-Butyl acetoacetate (Cell-AA), produced cellulose with β-ketoester functionality was then reacted with aniline and the amino acid glycine to produce Cellβ-AN and Cell-β-GL, respectively. Results: The adsorption efciency of the three polymers toward Pb(II) and various toxic metal ions present in sewage was evaluated as a function of adsorbent dose, time, temperature, pH value, and initial ion concentration to determine optimum adsorption conditions. The three polymers showed excellent efciency toward about 20 metal ions present in a sewage sample collected from the sewer. The adsorption process follows the Langmuir adsorption isotherm model with a second-order of adsorption rate, the calculated qe values (2.675, 15.252, 20.856 mg/g) were close to the experimental qe values (2.133, 13.91, 18.786 mg/g) for the three polymers Cell-AA, Cell-β-AG and Cell-β-AN, respectively. Molecular Dynamic (MD) and Monte Carlo (MC) simulations were performed on the three polymers complexed with Pb(II). Conclusion: The waste material of the olive industry was used as a precursor for making the target cellulose polymers with β-Amino Ester Pendant Group. The polymer was characterized by SEM, proton NMR, TGA, and FT-IR spectroscopy. The efcacy of adsorption was quantitative for metal ions present in a real sample of wastewater and the efciency didn’t drop even after 7 cycles of use. The results indicate the existence of strong complexation. The thermodynamic study results showed a spontaneous bonding between of Pb(II) and the polymers pendant groups expressed by the negative value of the Gibbs free energy.
Open Access
Micro sized interdigital capacitor for gases detection based on graphene oxide coating
(Springer, 2023) Vitoria Pascual, Ignacio; Armas, Dayron; Coronel Camones, Carlos Manuel; Algarra González, Manuel; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Mukhopadhyay, Subhas C.; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
A micro sized interdigital capacitor sensible to CO2 and NO is studied in this work. The photolithography technique enables to obtain fingers with dimensions of 10 × 500 µm and separated 7 µm between them. The deposition of a film composed of graphene oxide particles as the dielectrics of the capacitor allows to measure the gas concentration of CO2 and NO mixed with N2. The sensors were characterized in a gas chamber with a constant flow, obtaining promising results in changes of capacitance at 100 Hz. The sensors have a good linearity and sensitivity with a R2 = 0.996 and 5.026·10-1 pF/ % v/v for CO2 and R2=0.972 and 1.433·10-1 pF/ppb for NO.
Open Access
Catalyzed methods to synthesize pyrimidine and related heterocyclic compounds
(MDPI, 2023) Díaz Fernández, Marcos; Calvo Losada, Saturnino; Quirante, José Joaquín; Sarabia, Francisco; Algarra González, Manuel; Pino-González, María Soledad; Institute for Advanced Materials and Mathematics - INAMAT2
This review covers articles published in the period from 2010 to mid-2022 on synthetic advances in the formation of pyrimidine and related heterocyclic compounds. Special emphasis has been given to the different types of cycloadditions, taking into account the number of their components and leading to the formation of the pyrimidine ring. Due to the large number of publications on the Biginelli reaction and related reactions, this will be dealt with in a separate review in the near future.
Open Access
Nitrogen doped carbon dots as a photocatalyst based on biomass: a life cycle assessment
(Elsevier, 2023) Rodríguez-Carballo, Gabriela; Moreno-Tost, Ramón; Fernandes, Sónia; Esteves da Silva, Joaquim C.G.; Pinto da Silva, Luís; Castro Galiano, Eulogio; Algarra González, Manuel; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
The effectiveness of various transition metal phosphate-based acid catalysts, including vanadium and niobium, in the hydrothermal synthesis of carbon dots (CDs), has been assessed. Two sources of carbohydrates were employed for this: commercial xylose and liquor of xylose produced by processing olive pits. Catalysts were identified using the NH3-TPD, DTA/TG, XRD, and XPS techniques. The reaction was conducted for 4 h at a temperature of 180 °C. The existence of such nanoparticles, regardless of the carbohydrate source, was confirmed by an analysis of the features and characteristics of CDs nanoparticles. N-doped CDs with increased fluorescence were also created at the same time using a similar hydrothermal technique, and their photocatalytic activity was investigated. A Life Cycle Assessment (LCA) was conducted for both syntheses with the goal of comparing the environmental effects of the synthesis from commercial xylose to the synthesis from biomass. It was revealed that, although energy is the primary driver of both synthesis pathways' effect categories, the fundamental variations that seem to determine their relative sustainability are connected to the nature of the carbon precursor. Regarding the latter, it is determined that electricity has the greatest environmental impact.
Open Access
Low-cost Titania-Hydroxyapatite (TiHAp) nanocomposites were synthesized for removal of methylene blue under solar and UV irradiation
(Elsevier, 2025-07-01) Latifi, Souhayla; Saoiabi, Sanaa ; Alanazi, Mohammed M. ; Boukra, Omar ; Krime, Anas ; El Hammari, Larbi; Azzaoui, Khalil; Hammouti, Belkheir; Hanbali, Ghadir; Jodeh, Shehdeh; Saoiabi, Ahmad ; Sabbahi, Rachid ; Algarra González, Manuel; Abidi, Noureddine ; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Water pollution from industrial dyes like methylene blue (MB) poses significant environmental and health risks due to their toxicity and persistence. In this study, we synthesized a novel titania-hydroxyapatite (TiHAp) nanocomposite via a low-cost, scalable sol-gel method to address these challenges. The composite was comprehensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Photocatalytic degradation of MB under both solar and UV irradiation was evaluated using kinetic (pseudo-first-order and pseudo-second-order) and isotherm (Langmuir and Freundlich) models, demonstrating hydroxyapatite's key role in enhancing adsorption and facilitating effective interactions with the catalyst. Under optimized conditions, the TiHAp nanocomposite achieved 96.58 % degradation of MB at an initial concentration of 120 mg/L and retained over 95 % activity after five reuse cycles. These results illustrate that the synergistic combination of TiO₂'s photocatalytic activity and HAp's adsorptive capacity produces a highly effective composite for degrading organic pollutants. The study underscores the potential of TiHAp nanocomposites as sustainable materials for wastewater treatment applications, while future work will explore their performance against a broader range of contaminants under realistic environmental conditions.
Open Access
Synergistic enhancement of targeted wound healing by near-infrared photodynamic therapy and silver metal-organic frameworks combined with S- or N-doped carbon dots
(MDPI, 2024) Nesic, Maja D.; Popovic, Iva; Zakula, Jelena; Koricanac, Lela; Filipovic Trickovic, Jelena; Valenta Šobot, Ana; Jiménez, María Victoria; Algarra González, Manuel; Dučić, Tanja; Stepic, Milutin; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
The literature data emphasize that nanoparticles might improve the beneficial effects of near-infrared light (NIR) on wound healing. This study investigates the mechanisms of the synergistic wound healing potential of NIR light and silver metal–organic frameworks combined with nitrogen- and sulfur-doped carbon dots (AgMOFsN-CDs and AgMOFsS-CDs, respectively), which was conducted by testing the fibroblasts viability, scratch assays, biochemical analysis, and synchrotron-based Fourier transform infrared (SR-FTIR) cell spectroscopy and imaging. Our findings reveal that the combined treatment of AgMOFsN-CDs and NIR light significantly increases cell viability to nearly 150% and promotes cell proliferation, with reduced interleukin-1 levels, suggesting an anti-inflammatory response. SR-FTIR spectroscopy shows this combined treatment results in unique protein alterations, including increased α-helix structures and reduced cross-β. Additionally, protein synthesis was enhanced upon the combined treatment. The likely mechanism behind the observed changes is the charge-specific interaction of N-CDs from the AgMOFsN-CDs with proteins, enhanced by NIR light due to the nanocomposite’s optical characteristics. Remarkably, the complete wound closure in the in vitro scratch assay was achieved exclusively with the combined NIR and AgMOFsN-CDs treatment, demonstrating the promising application of combined AgMOFsN-CDs with NIR light photodynamic therapy in regenerative nanomedicine and tissue engineering.
Open Access
Nanoporous alumina support covered by imidazole moiety-based ionic liquids: optical characterization and application
(MDPI, 2022) Algarra González, Manuel; López Escalante, María Cruz; Martínez de Yuso, María Valle; Soto, Juan; Cuevas, Ana L.; Benavente, Juana; Institute for Advanced Materials and Mathematics - INAMAT2
This work analyzes chemical surface and optical characteristics of a commercial nanoporous alumina structure (NPAS) as a result of surface coverage by different imidazolium-based ionic liquids (1-butyl-3-metylimidazolium hexafluorophosphate, 3-methyl-1-octylimidazolium hexafluorophosphate, or 1-ethyl-3-methylimidazolium tetrafluoroborate). Optical characteristics of the IL/NPAS samples were determined by photoluminescence (at different excitation wavelengths (from 300 nm to 400 nm), ellipsometry spectroscopy, and light transmittance/reflectance measurements for a range of wavelengths that provide information on modifications related to both visible and near-infrared regions. Chemical surface characterization of the three IL/NPAS samples was performed by X-ray photoelectron spectroscopy (XPS), which indicates almost total support coverage by the ILs. The IL/NPAS analyzed samples exhibit different photoluminescence behavior, high transparency (<85%), and a reflection maximum at wavelength ~380 nm, with slight differences depending on the IL, while the refractive index values are rather similar to those shown by the ILs. Moreover, the illuminated I–V curves (under standard conditions) of the IL/NPAS samples were also measured for determining the efficiency energy conversion to estimate their possible application as solar cells. On the other hand, a computational quantum mechanical modeling method (DFT) was used to establish the most stable bond between the ILs and the NPAS support.