Nanostructures & Spectroscopies
Dernières publications
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High-Order Commensurate Zwitterionic Quinonoid Phase Induces a Nanoscale Dipole Lattice on Graphene ![doi link](plugins/aigle//images/ext_link.jpg)
Auteur(s): Nassar Gaelle, Cortés-Arriagada Diego, Sanhueza-Vega Luis, Landois P., Paillet M., Hrich H., Contreras S., Siri Olivier, Pascal Simon, Masson Laurence, Becker Conrad, Ranguis Alain, Parret R., Canard Gabriel, Leoni Thomas
(Article) Publié:
The Journal Of Physical Chemistry C, vol. p. (2024)
Ref HAL: hal-04609427_v1
DOI: 10.1021/acs.jpcc.4c01695
Exporter : BibTex | endNote
Résumé: Since the introduction of hybrid van der Waals heterostructures (h-vdWHs) for device architecture development, many vertically staked organic two-dimensional materials have been investigated in order to control transport properties. This article introduces a novel h-vdWH that achieves periodicinteraction by the development of a superlattice. We describe a complete investigation of the diphenyl-functionalized p-benzoquinonemonoimine zwitterion on highly oriented pyrolytic graphiteand monolayer graphene using high-resolution scanning tunneling microscopy images and numerical simulations. The molecular phase on both substrates exhibits a structurally identical antiparallel dipole alignment in a head-to-tail dimer configuration. Density functional theory calculations reveal that this molecularadsorption induces a local dipole at the graphene interface due to the rearrangement of the electron density distribution.
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Long‐time high‐pressure processing of a patatin‐rich potato proteins isolate: impact on aggregation and surface properties ![doi link](plugins/aigle//images/ext_link.jpg)
Auteur(s): Bahri Asma, Charpentier Claudine, Khati Paula, Le Parc R., Chevalier-Lucia Dominique, Picart-Palmade Laetitia
(Article) Publié:
International Journal Of Food Science And Technology, vol. p. (2024)
Ref HAL: hal-04582437_v1
DOI: 10.1111/ijfs.17192
Exporter : BibTex | endNote
Résumé: Summary In this study, a 4% (w/w) dispersion of a commercial patatin‐rich potato protein isolate (Po‐PI) was pressurised at 400 MPa up to 48 h at 20 °C. Protein aggregation induced by high‐pressure processing (HHP) was followed by dynamic light scattering, intrinsic fluorescence ( in‐situ or ex‐situ ) or SAXS analysis. Surface properties (surface hydrophobicity and interfacial properties) of the HHP‐induced aggregates were also investigated. A gradual dimer dissociation/protein unfolding was observed under pressure. Po‐PI exhibited a slow relaxation time under pressure. Long‐time HHP (>4 h) induced significant modification of the Po‐PI protein structure with partial non‐reversible unfolding. After 48 h of pressurisation at 400 MPa, large aggregates (160 nm) were obtained and a monomodal distribution in intensity and in number frequency was observed indicating a controlled aggregation. Up to 24 h of pressurisation at 400 MPa, intermediate states were obtained after high‐pressure release. SDS‐PAGE profiles showed that HHP‐induced aggregation of Po‐PI was driven by non‐covalent interactions. All high‐pressure processed dispersions displayed a higher surface hydrophobicity as compared to non‐treated Po‐PI. Po‐PI dispersion treated for 8 h at 400 MPa presented the lowest adsorption rate, the highest final surface tension and formed the most rigid interfacial film. Po‐PI showed resistance to moderate pressure levels (400 MPa) and long pressure application times were required to induce significant protein denaturation/aggregation (≥24 h) and to optimally modify its interfacial properties (8 h).
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Ball-milling for efficient synthesis of pyridine-containing iron(ii) photosensitizers ![doi link](plugins/aigle//images/ext_link.jpg)
Auteur(s): Rastoder Enita, Michel T., Lamaty Frédéric, Bantreil Xavier
(Article) Publié:
Rsc Mechanochemistry, vol. 1 p.116 - 122 (2024)
Ref HAL: hal-04539390_v1
DOI: 10.1039/D3MR00033H
Exporter : BibTex | endNote
Résumé: Photoredox catalysis is becoming more and more prevalent in the 21st century as a new tool for organic and polymer synthesis. In addition, this domain clearly fits the expectations of the twelve principles of green chemistry. However, access to metal containing photosensitizers is not always straightforward and can require long reaction times, the use of toxic solvents and multi-step synthesis. These are definitely drawbacks that could be overcome with the use of novel technologies. In this report, we develop a one-pot two-step synthesis of iron(II) photosensitizers using ball-milling. Overall reaction times were drastically reduced, no solvent was needed during the reaction, and ten complexes could be isolated in high yields (73–99%). Using a transparent milling jar, the formation of the complexes could be followed using in situ Raman spectroscopy.
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