A5082653053- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Advanced NMR Techniques and Applications
- Crystallography and molecular interactions
- Zeolite Catalysis and Synthesis
- Metal-Organic Frameworks: Synthesis and Applications
- Carbon Dioxide Capture Technologies
- Mesoporous Materials and Catalysis
- Covalent Organic Framework Applications
- Advanced Photocatalysis Techniques
- Membrane Separation and Gas Transport
- Solid-state spectroscopy and crystallography
- Advanced Nanomaterials in Catalysis
- Lipid Membrane Structure and Behavior
- Nonlinear Optical Materials Research
- Chemistry and Chemical Engineering
- NMR spectroscopy and applications
- Cellular transport and secretion
- Advanced Condensed Matter Physics
- Clay minerals and soil interactions
- Chemical Synthesis and Characterization
- Nanoparticle-Based Drug Delivery
- History and advancements in chemistry
- Nuclear materials and radiation effects
- Food Chemistry and Fat Analysis
University of Aveiro
2015-2025
Helmholtz-Institute Ulm
2019
Complejo Hospitalario Universitario de Santiago
2019
ETH Zurich
2013
Heptazine-based polymeric carbon nitrides (PCN) are promising photocatalysts for light-driven redox transformations. However, their activity is hampered by low surface area resulting in concentration of accessible active sites. Herein, we report a bottom-up preparation PCN nanoparticles with narrow size distribution (ca. 10±3 nm), which fully soluble water showing no gelation or precipitation over several months. They allow photocatalysis to be carried out under quasi-homogeneous conditions....
Two different structures of zeolites, faujasite (FAU) and Linde type A (LTA), were studied to investigate their suitability for drug delivery systems (DDS). The zeolites in the sodium form (NaY NaA) used as hosts encapsulation α-cyano-4-hydroxycinnamic acid (CHC). CHC, an experimental anticancer drug, was encapsulated both by diffusion liquid phase. These new systems, CHC@zeolite, characterized spectroscopic techniques (FTIR, 1H NMR, 13C 27Al solid-state MAS UV–vis), chemical analysis,...
Reaching a historic high of 36.3 gigatonnes in 2021, global CO2 emissions from fossil fuel combustion continue to increase at an alarming rate. removal technologies are part the solution tackle this crucial environmental challenge. Thus, development porous materials for storage and capture gas molecules (in particular, carbon storage) has attracted great interest both academic industrial communities due its potential mitigating atmospheric concentrations. Atomic-scale studies essential...
This study delves into the potential advantage of utilizing crab shells as sustainable solid adsorbents for CO
For the first time, solid-liquid phase diagrams of five binary mixtures saturated fatty acids are here presented. These formed caprylic acid (C(8:0))+capric (C(10:0)), capric (C(10:0))+lauric (C(12:0)), lauric (C(12:0))+myristic (C(14:0)), myristic (C(14:0))+palmitic (C(16:0)) and palmitic (C(16:0))+stearic (C(18:0)). The information used in these was obtained by differential scanning calorimetry (DSC), X-ray diffraction (XRD), FT-Raman spectrometry polarized light microscopy, aiming at a...
Here, we report that the dispersion and environment of acid sites anchored on a periodic mesoporous organosilica play crucial role in its catalytic activity water.
Two new cocrystals of theophylline were prepared by liquid assisted grinding. While compound 1 (theophylline:4-aminosalicylic acid 2:1) was characterized single crystal X-ray diffraction, the structure 2 (theophylline:4-aminobenzoic 1:1) determined combining powder diffraction (XRPD), solid-state NMR and DFT calculations. The use 1D/2D 1H high-resolution techniques provided structural insight on local length scales revealing internuclear proximities relative orientations between building...
Chemisorbent materials, based on porous aminosilicas, are among the most promising adsorbents for direct air capture applications, one of key technologies to mitigate carbon emissions. Herein, a critical survey all reported chemisorbed CO2 species, which may form in aminosilica surfaces, is performed by revisiting and providing new experimental proofs assignment distinct species thus far literature, highlighting controversial assignments regarding existence still under debate. Models...
This work entails a comprehensive solid-state NMR and computational study of the influence water CO2 partial pressures on CO2-adducts formed in amine-grafted silica sorbents. Our approach provides atomic level insights hypothesised mechanisms for capture under dry wet conditions tightly controlled atmosphere. The method used sample preparation avoids use liquid slurries, as performed previous studies, enabling molecular understanding, by NMR, amounts vapor (down to ca. 0.7 kPa) chemisorption...
Adsorption isotherms obtained through volumetric measurements are widely used to estimate the gas adsorption performance of porous materials. Nonetheless, there is always ambiguity regarding contributions chemi- and physisorption processes overall retained volume. In this work, we propose, for first time, use solid-state NMR (ssNMR) generate CO2 adsorbed onto an amine-modified silica sorbent. This method enables separation six individual physisorbed components, a feat only possible using...
Metal-organic frameworks (MOFs) are promising porous materials for CO2 adsorption due to their high surface area, tunable properties, and selective capabilities. The recently reported Calgary Framework 20 (CALF-20) MOF has very appealing capture properties: uptake capacity; low regeneration energy; durability (>450 000 cycles) under steam wet acid gases; simple scalable synthesis. This study investigates the microwave (MW)-assisted synthesis of CALF-20, which reduces reaction time 12-fold...
Nonfunctionalized and functionalized periodic mesoporous phenylene–silicas (Ph–PMOs) with different kinds of amine groups were prepared their capacity to uptake CO2 CH4 molecules experimentally evaluated considering biogas upgrading. It was found that aminopropyl grafted the free silanols Ph–PMO displayed highest selectivity for gas, adsorbing 26.1 times more than at 25 °C. The interaction effect surface these materials or obtained through calculation Henry constants, adsorption mechanisms...
We present a complete set of experimental approaches for the NMR assignment powdered tripeptide glutathione at natural isotopic abundance, based on J-coupling and dipolar techniques combined with (1)H CRAMPS decoupling. To fully assign spectra, two-dimensional (2D) high-resolution methods, such as (1)H-(13)C INEPT-HSQC/PRESTO heteronuclear correlations (HETCOR), (1)H-(1)H double-quantum (DQ), (1)H-(14)N D-HMQC correlation experiments, have been used. support interpretation data, periodic...
The wealth of site-selective structural information on CO2 speciation, obtained by spectroscopic techniques, is often hampered the lack easy-to-control synthetic routes. Herein, an alternative experimental protocol that relies high sensitivity 13 C chemical shift anisotropy (CSA) tensors to proton transfer, presented unambiguously distinguish between ionic/charged and neutral species, formed upon adsorption in amine-modified porous materials. Control surface amine spacing was achieved...
Yeast cell walls undergo modifications during the brewing process, leading to a remodelling of their architecture. One significant change is increased insolubility wall glycogen pool, likely due formation covalent bonds between and polysaccharides. To verify this hypothesis, we extracted brewer's spent yeast with 4 M KOH, obtaining an insoluble glucan fraction (AE.4 M) primarily composed (α1 → 4)- (1 3)-linked Glc residues. Dynamic nuclear polarization solid-state NMR AE.4 revealed distinct...
Thermal stability of lanthanide (Ln = La, Nd, Gd, Yb) containing glass and glass–ceramics (GCs) was characterized for their application as sealants solid oxide fuel cells (SOFCs). X-ray diffraction (XRD) in conjunction with the Rietveld-RIR solid-state NMR techniques employed to quantify crystalline amorphous fractions glasses sintered/heat treated at 850 °C air 1–1000 h. The structure phase evolution Ln aluminosilicate depend markedly on Ln3+ cation field strength over both short...
The reactivity of the active pharmaceutical ingredient azelaic acid (AA) with carboxylic acid, alcohol, amine, and amide based co-formers was screened. Five new multicomponent crystal forms AA were obtained by liquid assisted grinding conventional solution methods. forms: (i) a co-crystal 4,4′-bipyridine (AA:BIP, 1), (ii) an anhydrous hydrated molecular salt piperazine (AA:PIP, 2 3), (iii) two salts morpholine (AA:MORPH, 4) 1,4-diazobicyclo[2.2.2]octane (AA:DABCO, 5), fully characterized...
Two-dimensional 1H-31P heteronuclear correlation NMR of trimethylphosphine oxide (TMPO) adsorbed in zeolites, tandem with DFT calculations, challenges previous one-dimensional 31P assignments, enabling the unambiguous discrimination Brønsted and Lewis acid sites, extending understanding TMPO:Brønsted complexes formed distinct stoichiometries at HZSM-5 zeolite surface, proton-transfer mechanism.
Abstract Heptazine‐based polymeric carbon nitrides (PCN) are promising photocatalysts for light‐driven redox transformations. However, their activity is hampered by low surface area resulting in concentration of accessible active sites. Herein, we report a bottom‐up preparation PCN nanoparticles with narrow size distribution (ca. 10±3 nm), which fully soluble water showing no gelation or precipitation over several months. They allow photocatalysis to be carried out under quasi‐homogeneous...
Abstract Nanoscale flows of liquids can be revealed in various biological processes and underlie a wide range nanofluidic applications. Though the integral characteristics these systems, such as permeability effective diffusion coefficient, measured experiments, behaviour within nanochannels is still matter speculation. Herein, we used combination quadrupolar solid-state NMR spectroscopy, computer simulation, dynamic vapour sorption measurements to analyse water inside peptide nanochannels....
5-FU release profiles reveled to be dependent on the host structures. DDS led significant potentiation of effect in cancer cells.