All posts by Pau

Additives on the Ca(BH) system

2013-02-13Our Publications11B-NMR, borohydrides, hydrogen-desorption, hydrogen-Storage, solid-state nmrPau

“Chemical State, Distribution and Role of Ti- and Nb-Based Additives on the Ca(BH₄)₂ System” by Christian Bonatto Minella, Eva Pellicer, Emma Rossinyol, Fahim Karini, Claudio Pistidda,Sebastiano Garroni, Chiara Milanese, Pau Nolis, Maria Dolors Baró, Oliver Gutfleisch, Klaus Pranzas, Andreas Schreyer, Thomas Klassen, Rüdiger Bormann and Martin Dornheim. The Journal of Physical Chemistry C. 117:4394-4403 (2013). DOI: 10.1021/jp3116275

Light metal tetrahydroborates are regarded as promising materials for solid state hydrogen storage. Due to both a high gravimetric hydrogen capacity of 11.5 wt. % and an ideal de-hydrogenation enthalpy of 32 kJ mol-1 H2, Ca(BH4)2 is considered to be one of the most interesting compounds in this class of materials. In this work, a comprehensive investigation of the effect of different selected additives (TiF4, NbF5, Ti-isopropoxide and CaF2) on the reversible hydrogenation reaction of calcium borohydride is presented combining different investigation techniques. Continue reading Additives on the Ca(BH) system →

Ca(BH₄)₂ + MgH₂: Desorption Reaction

2013-02-11Our Publications11B-NMR, borohydrides, hydrogen-desorption, hydrogen-Storage, solid-state nmrPau

“Ca(BH4)2 + MgH2: Desorption Reaction and Role of Mg on its Reversibility” by Christian Bonatto Minella, Claudio Pistidda, Sebastiano Garroni, Pau Nolis, Maria Dolors Baró, Oliver Gutfleisch, Thomas Klassen, Rüdiger Bormann, and Martin Dornheim. The Journal of Physical Chemistry C. 117:3846-3852 (2013). DOI: 10.1021/jp312271s

The Ca(BH4)2-MgH2 composite system represents a promising candidate for mobile hydrogen storage due to a 10.5 wt. % theoretical hydrogen storage capacity and an estimated equilibrium temperature lower than 160 °C. For this system, the reversibility was achieved without further addition of additives. Continue reading Ca(BH₄)₂ + MgH₂: Desorption Reaction →

Chiral secondary structure in β-peptides determined by NMR

2012-10-04Our Publicationschirality, conformational-study, foldamers, hydrogen-bonds, peptides, secondary structuresPau

“Secondary Structure of Short β-Peptides as the Chiral Expression of Monomeric Building Units: a Rational and Predictive Model”Esther Gorrea, Gabor Pohl, Pau Nolis, Sergio Celis, Kepa K Burusco, Vicenç Branchadell, András Perczel, and Rosa M. Ortuño. Journal Of Organic Chemistry. ACCEPTED 2012 DOI: 10.1021/jo302034b

Chirality of the monomeric residues controls and determines the prevalent folding of small oligopeptides (from di- to tetramers) composed of the 2-aminocyclobutane-1-carboxylic acid (ACBA) derivatives with the same or different absolute and relative configuration. The cis-form of the monomeric ACBA gives rise to two conformers, namely Z6 and Z8, while the trans-form manifests uniquely as an H8 structure. Continue reading Chiral secondary structure in β-peptides determined by NMR →

Organic composition in soil studied by solid state NMR

2012-09-14Our Publications13C-NMR, climate change, ecology, soil, solid-state nmrPau

“Changes in soil bacterial community: diversity, composition and function triggered by drought-induced gap succession preceded changes in soil C stocks and quality ” Curiel-Yuste J., Barba J., Fernandez-Gonzalez A.J., Fernandez-Lopez M., Mattana S., Martinez-Vilalta J., Pau Nolis, Lloret F. Ecology and Evolution. Accepted 2012.

We investigated soil bacterial taxonomic composition, soil respiration and soil organic matter quantity and quality in a mixed Mediterranean forest where the Scots pine (Pinus sylvestris) population is affected by climatic drought-induced die-off, and replaced by Holm-oak (Quercus ilex) populations as the dominant tree species. Continue reading Organic composition in soil studied by solid state NMR →

Sodium mobility on dry-cured ham studied by T₂ relaxation times

2012-08-27Our Publications23Na-NMR, dry-cured ham, food-science, T2-relaxationPau

“High pressure processing of dry-cured ham: Ultrastructural and molecular changes affecting sodium and water dynamics” Pierre A. Picoueta, Xavier Sala, Núria Garcia-Gila, Pau Nolis, Maddalena Colleo, Teodor Parella, Jacint Arnau. Innovative Food Science & Emerging Technologies. Available online 4 August 2012. DOI: 10.1016/j.ifset.2012.07.008

High pressure processing (HPP) has become a popular method to reduce bacterial load on dry-cured ham. However, HPP processed hams tend to present higher saltiness than non-processed ones. In this study was evaluated the effect of processing Biceps femoris samples of 9 dry-cured hams aged for 15 months at a pressure of 0.1, 300, 600 and 900 MPa. 23Na-Nuclear Magnetic Resonance (NMR) relaxation values were used to determine the mobility of sodium. Continue reading Sodium mobility on dry-cured ham studied by T₂ relaxation times →

Cryoprobe: a key tool for the NMR characterization of small amount of peptides

2012-04-29Our Publications19F-NMR, cryoprobe, HMBC, peptidesPau

“Fast cysteine labelling of peptides promoted by an adjacent arginine has been observed with a standard labelling agent specific for amines, N-succinimidyl 4-[18F]fluorobenzoate” Sergio Abad, Pau Nolis, Juan D. Gispert, Jan Spengler, Fernando Albericio, Santiago Rojas and José R. Herance, ChemComm, Volume 48, pages 6118-6120, April 2012. DOI: 10.1039/C2CC32095A

Fast cysteine labelling of peptides promoted by an adjacent arginine has been observed with a standard labelling agent specific for amines, N-succinimidyl 4-[18F]fluorobenzoate. HMBC experiment was the key experiment to corroborate this treat. The small amounts of some peptides herein studied required the sensitivty beneffits of a 500 MHz equipped with TCI cryprobe.

HR-MAS: a key technique to study Nanoparticles

2012-01-26Our Publications31P-NMR, aromatic hydrogenation, HRMAS, ligand effect, nanoparticles, ruthenium nanoparticles, surface bound molecules characterizationPau

“Phosphine Stabilized Ruthenium Nanoparticles: the Effect of the Nature of the Ligand in Catalysis” David González-Gálvez, Pau Nolis, Karine Philippot, Bruno Chaudret and Piet W. N. M. van Leeuwen. ACS Catalysis, Volume 2, Pages 317-321, January 2012 DOI: 10.1021/cs200633k

Various ligands not forming monometallic complexes were used for Ru nanoparticle stabilization, enabling the control of size, shape and electronic properties. HRMAS NMR spectroscopy allowed us to study surface-bound molecules, evidencing ligand hydrogenation and decomposition of THF during the RuNP synthesis. Continue reading HR-MAS: a key technique to study Nanoparticles →

Designing hybrid foldamers

2011-10-16Our Publicationsconformational-study, foldamers, hydrogen-bonds, peptides, secondary structuresPau

“Designing hybrid foldamers: The effect on the peptide conformational bias of beta- versus alpha- and gamma-linear residues in alternation with (1R,2S)-2-aminocyclobutane-1-carboxylic acid” Sergi Celis, Esther Gorrea, Pau Nolis, Ona Illa, Rosa Maria Ortuño. Organic and Biomolecular Chemistry. Volume 10, Pages 861-868, October 2011 DOI: 10.1039/C1OB06575K

Several oligomers constructed with (1R,2S)-2-aminocyclobutane-1-carboxylic acid and glycine, beta-alanine, and gamma-amino butyric acid (GABA), respectively, joined in alternation have been synthesized and studied by means of NMR and CD experiments as well as with computational calculations. Continue reading Designing hybrid foldamers →

Experimental evidence of Na₂[B₁₂H₁₂] and Na formation in the desorption pathway of the 2NaBH₄ + MgH₂ system

2011-07-18Our Publications11B-NMR, 23Na-NMR, borohydrides, hydrogen-desorption, hydrogen-Storage, solid-state nmrPau

“Experimental evidence of Na2[B12H12] and Na formation in the desorption pathway of the 2NaBH4+ MgH2 system”, by Sebastiano Garroni, Chiara Milanese, Daphiny Pottmaier, Gabriele Mulas, Pau Nolis, Alessandro Girella, Riccarda Caputo, David Olid-Britos, Francesc Teixidor, Marcello Baricco, Amedeo Marini, Santiago Suriñach, and Maria Dolores Baró. The Journal of Physical Chemistry C, Volume 115, Pages 16664-16671, July 2011. DOI: 10.1021/jp202341j

In the present work we report the desorption pathway of the 2NaBH4 + MgH2 system. Ex-situ X-ray powder diffraction (XRPD) and solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) measurements have been performed on samples heat-treated up to 450°C for different times. Ex-situ X-ray powder diffraction experiments conducted on fully desorbed samples allowed to identify nanocrystalline MgB2 and metallic Na as dehydrogenation products. Continue reading Experimental evidence of Na₂[B₁₂H₁₂] and Na formation in the desorption pathway of the 2NaBH₄ + MgH₂ system →

Structural study of γ,γ-peptides

2011-05-19Our Publicationschirality, conformational-study, hydrogen-bonds, nanometric size, peptides, secondary structures, self-assembly, vesiclesPau

“Synthesis and structural study of highly constrained hybrid cyclobutane-proline γ,γ-peptides” by R. Gutiérrez-Abad, D. Carbajo, P. Nolis, C. Acosta-Silva, J. A. Cobos, O. Illa, M. Royo and R. Ortuño. Aminoacids, Volume 41, pages 673-686, 2011. DOI: 10.1007/s00726-011-0912-4.

Two diastereomeric series of hybrid γ,γ-peptides derived from conveniently protected derivatives of (1R,2S)- and (1S,2R)-3-amino-2,2-dimethylcyclobutane-1-carboxylic acid and cis-4-amino-l-proline joined in alternation have efficiently been prepared through convergent synthesis. Continue reading Structural study of γ,γ-peptides →

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