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15 results on '"School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...)"'

1. Clean synthesis of linear and star amphiphilic poly(ε-caprolactone)-block-poly(ethyl ethylene phosphonate) block copolymers: assessing self-assembly and surface activity

Author

Timo Rheinberger, Steven M. Howdle, Payal Baheti, Patrick Lacroix-Desmazes, Olinda Gimello, Frederik R. Wurm, Cécile Bouilhac, Sustainable bio-inspired organic materials chemistry, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Max-Planck-Institut für Polymerforschung (MPI-P), Max-Planck-Gesellschaft, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., and School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...)

Subjects
Ethylene, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Pollution, 6. Clean water, 0104 chemical sciences, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, Monomer, chemistry, Chemical engineering, Polymerization, Amphiphile, Copolymer, Environmental Chemistry, Self-assembly, 0210 nano-technology, Caprolactone, Ethylene glycol, ComputingMilieux_MISCELLANEOUS
Abstract

Anionic ring-opening polymerization (AROP) of 2-ethyl-2-oxo-1,3,2-dioxaphospholane (EP) has been utilized to create alternative hydrophilic moieties for utilization in surfactants. The current “go-to” hydrophilic unit is poly(ethylene glycol) (PEG), but this is non-biodegradable and there is some evidence that its use can lead to accumulation of toxic by-products. We have created new approaches leading to water-dispersible, fully degradable amphiphilic block copolymers. Our approach utilized poly(ε-caprolactone)-based macroinitiators in a solvent free process with organocatalyst DBU. We have prepared a comprehensive set of novel amphiphilic PCL-b-PEP block copolymers including linear diblock, triblock and star diblock copolymers characterized by SEC, 1H and 31P NMR and MALDI-TOF analyses. Supercritical carbon dioxide (scCO2) was exploited to efficiently extract the residual EP monomer leading to significantly increased gravimetric yields of purified product compared to conventional techniques such as dialysis. The self-assembly of the amphiphilic copolymers in water was investigated by DLS and cryo-TEM and their surface-activity as a function of concentration was investigated by tensiometry showing behavior that matches or exceeds commercially available surfactants.

Published
2020

2. An integrated approach to determine interactive genotoxic and global gene expression effects of multiwalled carbon nanotubes (MWCNTs) and benzo[a]pyrene (BaP) on marine mussels: evidence of reverse ‘Trojan Horse’ effects

Author

Lorna J. Dallas, Audrey Barranger, Volker M. Arlt, Mohamed Banni, Andrei N. Khlobystov, Michael Moore, James W. Readman, Yann Aminot, Awadhesh N. Jha, Susanna Sforzini, Rhys W. Lodge, Aldo Viarengo, Nicola Weston, Graham A. Rance, School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Centre for Chemical Sciences, University of Plymouth, Plymouth PL4 8AA, UK, Department of Sciences and Technological Innovation (DiSIT), Università degli Studi del Piemonte Orientale - Amedeo Avogadro (UPO), Nanoscale and Microscale Research Centre, University of Nottingham, University Park, Nottingham NG7 2RD, UK, Institut Supérieur d'Agronomie de Chott-Mariem, Department of Analytical, Environmental and Forensic Sciences, King’s College London, MRC-PHE Centre for Environmental & Health, London SE1 9NH, UK, Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3HD, UK, and Dipartimento di Scienze dell'Ambiente e della Vita (DiSAV)

Subjects
animal structures, Biomedical Engineering, chemistry.chemical_element, 02 engineering and technology, 010501 environmental sciences, Toxicology, Multiwalled carbon, complex mixtures, 01 natural sciences, chemistry.chemical_compound, Adsorption, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], Gene expression, Benzo(a)pyrene, polycyclic compounds, Animals, 14. Life underwater, van der Waals interactions, 0105 earth and related environmental sciences, Mytilus, Pollutant, integumentary system, Nanotubes, Carbon, benzo[a]pyrene, Biota, multi-walled carbon nanotubes, Integrated approach, 021001 nanoscience & nanotechnology, Gene Expression Regulation, Mytilus galloprovincialis, chemistry, adsorption, 13. Climate action, Environmental chemistry, Comet Assay, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, 0210 nano-technology, Carbon, Water Pollutants, Chemical, DNA Damage
Abstract

International audience; The interactions between carbon-based engineered nanoparticles (ENPs) and organic pollutants might enhance the uptake of contaminants into biota. The present integrated study aimed to assess this potential ‘Trojan Horse’, probing the interactive effects of purpose-made multi-walled carbon nanotubes (MWCNTs), a representative ENP, and benzo[a]pyrene (BaP), a ubiquitous polycyclic aromatic hydrocarbon (PAH) pollutant, on the marine mussel Mytilus galloprovincialis. Mussels were exposed to MWCNTs and BaP either alone or in various combinations. The co-exposure of BaP with MWCNTs revealed that the presence of MWCNTs enhanced the aqueous concentrations of BaP, thereby reducing the uptake of this pollutant by mussels as evidenced by lowering BaP concentrations in the tissues. Determination of DNA damage (comet assay) showed a concentration-dependent response for BaP alone which was absent when MWCNTs were present. Global gene expression using microarray analyses indicated that BaP and MWCNTs, in combination, differentially activated those genes which are involved in DNA metabolism compared to the exposures of BaP or MWCNTs alone, and the gene expression response was tissue-specific. Mechanisms to explain these results are discussed and relate primarily to the adsorption of BaP on MWCNTs, mediated potentially by van der Waals interactions. The use of a novel approach based on gold-labeled MWCNTs to track their uptake in tissues improved the traceability of nanotubes in biological samples. Overall, our results did not indicate the ‘Trojan Horse’ effects following co-exposure to the contaminants and clearly showed that the adsorption of BaP to MWCNTs modified the uptake of the pollutant in marine mussels.

Published
2019

3. Polymerisation-Induced Self-Assembly (PISA) as a straightforward formulation strategy for Stimuli-Responsive Drug Delivery Systems and Biomaterials: Recent Advances

Author

Hien Phan, Jacques Penelle, Benoit Couturaud, Vincenzo Taresco, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., and School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...)

Subjects
Emulsion solvent evaporation, Stimuli responsive, Polymers, Computer science, [SDV]Life Sciences [q-bio], Microfluidics, Biomedical Engineering, review, biomedicine, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Drug Delivery Systems, Amphiphile, phramaceutical sciences, General Materials Science, smart particles, PISA, self-assembly, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Drug Liberation, [CHIM.POLY]Chemical Sciences/Polymers, Polymerization, polymerization, Drug delivery, drug delivery, Nanoparticles, Self-assembly, Nanocarriers, 0210 nano-technology
Abstract

International audience; Stimuli-responsive amphiphilic block copolymers have emerged as promising nanocarriers for enhancing site-specific and on-demand drug release in response to a range of stimuli such as pH, the presence of redox agents, or temperature. The formulation of amphiphilic block copolymers into polymeric drug-loaded nanoparticles is typically achieved by various methods (e.g. oil-in-water emulsion solvent evaporation, solid dispersion, microphase separation, dialysis or microfluidic). Despite the several progresses that have been made, there remain many challenges to overcome to produce reliable polymeric systems. The main weakness of the above methods is that they imply very low solid contents (< 1 wt%) and multiple-step procedures, thus limiting their scope. Recently, a new self-assembly methodology, polymerisation-induced self-assembly (PISA), has shown great promise in the production of polymer-derived particles in a straightforward one-pot approach, whilst facilitating high yield, scalability, and cost-effectiveness for pharmaceutical industry protocols. We therefore focus this review primarily on the most recent studies involving in the design and preparation of PISA-generated nano-objects which are responsive to specific stimuli, thus providing an insight into how PISA may become an effective formulation strategy for the preparation of precisely tailored drug delivery systems and biomaterials, while some of the current challenges, conundrum, and limitations are also critically discussed.

Published
2020

4. Electronic Circular Dichroism Spectroscopy of Proteins

Author

Matthieu Réfrégiers, François Auvray, David M. Rogers, Naomi T. Dyer, Jonathan D. Hirst, Sarah B. Jasim, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Synchrotron SOLEIL (SSOLEIL), and Centre National de la Recherche Scientifique (CNRS)

Subjects
Circular dichroism, Materials science, General Chemical Engineering, Exciton, Biochemistry (medical), Ab initio, 02 engineering and technology, General Chemistry, Biomolecular structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Quantum chemistry, 0104 chemical sciences, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Atomic electron transition, Chemical physics, Materials Chemistry, Environmental Chemistry, Density functional theory, 0210 nano-technology, Spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

Electronic circular dichroism (CD) spectroscopy is an important tool for the elucidation of biomolecular structure. This review describes the latest progress and developments in experimental and theoretical studies of proteins using CD spectroscopy, including time-resolved measurements, oriented CD, and state-of-the-art experiments using polarized UV light from high-energy synchrotron radiation. Statistical and machine learning methods for the analysis of experimental spectra are surveyed. Computational methods employed to predict CD spectra from structure include ab initio quantum chemistry techniques, time-dependent density functional theory, and exciton theory. We describe recent computations using exciton theory, where we outline the importance of electronic-vibrational coupling and the influence of electrostatics of the protein environment on the electronic transitions in the chromophores responsible for CD signals in the near UV. Improvements in the accuracy of the computational approaches should allow more quantitative studies, applying a combination of experimental data and modeling to a variety of interesting questions.

Published
2019

5. Creating nanoporous graphene with swift heavy ions

Author

Flyura Djurabekova, Kai Nordlund, Arkady V. Krasheninnikov, E. H. Åhlgren, Marika Schleberger, Marko Karlušić, Henning Lebius, Milko Jakšić, Oliver Ochedowski, Rasim Mirzayev, Jani Kotakoski, Roland Kozubek, Aleksi A. Leino, Henrique Vázquez, Department of Physics, University of Helsinki, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Fakultät für Physik (CeNIDE), Universität Duisburg-Essen [Essen], Universität Wien, Department of Physics and Center for Nanointegration, University of Duisburg-Essen (CENIDE), Matériaux, Défauts et IRradiations (MADIR), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), Institut Ruđer Bošković (IRB), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Applied Physics [Aalto], Aalto University, National University of Science and Technology (MISIS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Universität Duisburg-Essen = University of Duisburg-Essen [Essen], Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, two-temperature model, Ionic bonding, 02 engineering and technology, 114 Physical sciences, 01 natural sciences, Ion, law.invention, symbols.namesake, law, 0103 physical sciences, General Materials Science, 010306 general physics, graphene, swift heavy ions, ta114, Swift heavy-ion irradiation, Nanoporous, Graphene, Ion track, ion irradiation, General Chemistry, Physik (inkl. Astronomie), 021001 nanoscience & nanotechnology, Nanopore, Chemical physics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], symbols, Atomic physics, 0210 nano-technology, Raman spectroscopy, atomistic simulations, Graphene nanoribbons
Abstract

This article has an erratum: DOI 10.1016/j.carbon.2017.03.065 We examine swift heavy ion-induced defect production in suspended single layer graphene using Raman spectroscopy and a two temperature molecular dynamics model that couples the ionic and electronic subsystems. We show that an increase in the electronic stopping power of the ion results in an increase in the size of the pore-type defects, with a defect formation threshold at 1.22–1.48 keV/layer. We also report calculations of the specific electronic heat capacity of graphene with different chemical potentials and discuss the electronic thermal conductivity of graphene at high electronic temperatures, suggesting a value in the range of 1 Wm−1 K−1. These results indicate that swift heavy ions can create nanopores in graphene, and that their size can be tuned between 1 and 4 nm diameter by choosing a suitable stopping power.

Published
2017

6. Time resolved transient circular dichroism spectroscopy using synchrotron natural polarization

Author

Frank Wien, D. Dennetiere, Frédéric Jamme, Bruno Lagarde, Claude Menneglier, Bastien Nay, François Auvray, Alexandre Giuliani, Séverine Zirah, Matthieu Réfrégiers, Jonathan D. Hirst, François Polack, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), University of Nottingham, UK (UON), Département Caractérisation et Elaboration des Produits Issus de l'Agriculture (CEPIA), Institut National de la Recherche Agronomique (INRA), École polytechnique (X), École Nationale Supérieure de Techniques Avancées (ENSTA Paris), Institut Polytechnique de Paris (IP Paris), Muséum national d'Histoire naturelle (MNHN), Molécules de Communication et Adaptation des Micro-organismes (MCAM), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Laboratoire de synthèse organique (DCSO), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de physiologie cérébrale (LPC - UMR 8118), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5), Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Circular dichroism, Materials science, Infrared, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Synchrotron radiation, 02 engineering and technology, medicine.disease_cause, Experimental Methodologies, 01 natural sciences, law.invention, ARTICLES, Optics, law, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, 0103 physical sciences, synchrotron, medicine, lcsh:QD901-999, structure, 010306 general physics, Spectroscopy, Instrumentation, ComputingMilieux_MISCELLANEOUS, Radiation, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], business.industry, Circular Dichroism, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Polarization (waves), Synchrotron, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM], time resolved spectroscopy, lcsh:Crystallography, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Time-resolved spectroscopy, 0210 nano-technology, business, protein, Ultraviolet
Abstract

International audience; Ultraviolet (UV) synchrotron radiation circular dichroism (SRCD) spectroscopy has made an important contribution to the determination and understanding of the structure of bio-molecules. In this paper, we report an innovative approach that we term time-resolved SRCD (tr-SRCD), which overcomes the limitations of current broadband UV SRCD setups. This technique allows accessing ultrafast time scales (down to nanoseconds), previously measurable only by other methods, such as infrared (IR), nuclear magnetic resonance (NMR), fluorescence and absorbance spectroscopies and small angle X-ray scattering (SAXS). The tr-SRCD setup takes advantage of the natural polarisation of the synchrotron radiation emitted by a bending magnet to record broadband UV CD faster than any current SRCD setup, improving the acquisition speed from 10 mHz to 130 Hz and the accessible temporal resolution by several orders of magnitude. We illustrate the new approach by following the isomers concentration changes of an azopeptide after a photoisomerisation. This breakthrough in SRCD spectroscopy opens up a wide range of potential applications to the detailed characterisation of biological processes, such as protein folding, protein-ligand binding.

Published
2019

7. Antagonistic Interactions between Benzo[a]pyrene and Fullerene (C60) in Toxicological Response of Marine Mussels

Author

Audrey Barranger, Nicola Weston, James W. Readman, Yann Aminot, Andrei N. Khlobystov, Volker M. Arlt, Vikram Sharma, Farida Akcha, Michael N Moore, Graham A. Rance, Awadhesh N. Jha, Laura M. Langan, Plymouth University, Nanoscale and Microscale Research Centre, University of Nottingham, University Park, Nottingham NG7 2RD, UK, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Laboratoire d'Écotoxicologie (LEX), Biogéochimie et Ecotoxicologie (BE), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3HD, UK, Department of Analytical, Environmental and Forensic Sciences, King’s College London, MRC-PHE Centre for Environmental & Health, London SE1 9NH, UK, NE/L006782/1, Natural Environment Research Council, EP/L022494/1, Engineering and Physical Sciences Research Council, School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK, School of Biomedical Sciences, University of Plymouth, Plymouth PL4 8AA, UK, Centre for Chemical Sciences, University of Plymouth, Plymouth PL4 8AA, UK, Laboratoire d'Ecotoxicologie, and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)

Subjects
Proteomics, animal structures, DNA damage, General Chemical Engineering, 010501 environmental sciences, 01 natural sciences, lcsh:Chemistry, 03 medical and health sciences, chemistry.chemical_compound, proteomics, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], Protein biosynthesis, Mussels, nC60, General Materials Science, KEGG, Co-exposure, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0105 earth and related environmental sciences, 0303 health sciences, biology, co-exposure, fungi, Translation (biology), B[a]P, nC(60), biology.organism_classification, Trojan horse effect, Mytilus, 3. Good health, mussels, lcsh:QD1-999, chemistry, Biochemistry, Benzo(a)pyrene, Pyrene, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, NC
Abstract

This study aimed to assess the ecotoxicological effects of the interaction of fullerene (C60) and benzo[a]pyrene (B[a]P) on the marine mussel, Mytilus galloprovincialis. The uptake of nC60, B[a]P and mixtures of nC60 and B[a]P into tissues was confirmed by Gas Chromatography&ndash, Mass Spectrometry (GC&ndash, MS), Liquid Chromatography&ndash, High Resolution Mass Spectrometry (LC&ndash, HRMS) and Inductively Coupled Plasma Mass Spectrometer (ICP&ndash, MS). Biomarkers of DNA damage as well as proteomics analysis were applied to unravel the interactive effect of B[a]P and C60. Antagonistic responses were observed at the genotoxic and proteomic level. Differentially expressed proteins (DEPs) were only identified in the B[a]P single exposure and the B[a]P mixture exposure groups containing 1 mg/L of C60, the majority of which were downregulated (~52%). No DEPs were identified at any of the concentrations of nC60 (p &lt, 0.05, 1% FDR). Using DEPs identified at a threshold of (p &lt, 0.05, B[a]P and B[a]P mixture with nC60), gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that these proteins were enriched with a broad spectrum of biological processes and pathways, including those broadly associated with protein processing, cellular processes and environmental information processing. Among those significantly enriched pathways, the ribosome was consistently the top enriched term irrespective of treatment or concentration and plays an important role as the site of biological protein synthesis and translation. Our results demonstrate the complex multi-modal response to environmental stressors in M. galloprovincialis.

Published
2019
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8. A comprehensive comparison of dye-sensitized NiO photocathodes for solar energy conversion

Author

Yoann Farré, Charlotte A. Clark, Fabrice Odobel, Nicolas Kaeffer, Yann Pellegrin, Christopher J. Wood, Luca D'Amario, Lea Roberta Carbone, Christopher D. J. Parmenter, Danilo Dini, Frédéric Oswald, Lee A. Stevens, Benjamin Dietzek, Alessandro La Torre, Elizabeth A. Gibson, Licheng Sun, Colin E. Snape, Michael W. Fay, Gareth H. Summers, Ke Fan, Stéphanie Narbey, Maximilian Braeutigam, Vincent Artero, Leif Hammarström, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Laboratoire de Chimie et Biologie des Métaux (LCBM - UMR 5249), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Institute of Photonic Technology (IPHT), IPHT Jena: Institute of Photonic Technology, Department of Chemistry University 'La Sapienza', Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Department of Chemistry-Ångström laborator, Uppsala University, Royal Institute of Technology [Stockholm] (KTH ), Department of Materials Science and Engineering, KTH (KTH), Department of Materials Science and Engineering, KTH, Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Solaronix, rue de l'Ouriette 129, CH-1170 Aubonne, Switzerland, Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, University Park, Nottingham, UK, Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, UK (UON), Department of Chemical and Environmental Engineering [Nottingham], Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Uppsala University, and Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Fabrication, General Physics and Astronomy, Nanotechnology, 02 engineering and technology, 010402 general chemistry, Electrochemistry, Physical Chemistry, 7. Clean energy, 01 natural sciences, law.invention, law, Solar cell, Physical and Theoretical Chemistry, Fysikalisk kemi, business.industry, Chemistry, Non-blocking I/O, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Solar cell efficiency, Electrode, Photocatalysis, Optoelectronics, 0210 nano-technology, business, Mesoporous material
Abstract

International audience; We investigated a range of different mesoporous NiO electrodes prepared by different research groups and private firms in Europe to determine the parameters which influence good quality photoelectrochemical devices. This benchmarking study aims to solve some of the discrepancies in the literature regarding the performance of p-DSCs due to differences in the quality of the device fabrication. The information obtained will lay the foundation for future photocatalytic systems based on sensitized NiO so that new dyes and catalysts can be tested with a standardized material. The textural and electrochemical properties of the semiconducting material are key to the performance of photocathodes. We found that both commercial and non-commercial NiO gave promising solar cell and water-splitting devices. The NiO samples which had the two highest solar cell efficiency (0.145% and 0.089%) also gave the best overall theoretical H2 conversion.

Published
2016

9. Photoionization dynamics of cis-dichloroethene from investigation of vibrationally resolved photoelectron spectra and angular distributions

Author

E. V. Gromov, D.M.P. Holland, Minna Patanen, Ivan Powis, R.C. Menzies, Christophe Nicolas, A. D. Skitnevskaya, Alexander B. Trofimov, Catalin Miron, E. Antonsson, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Daresbury Laboratory, Laboratory of Quantum Chemistry, Irkutsk State University, Irkutsk State University (ISU), Theoretische Chemie Universität Heidelberg, Universität Heidelberg [Heidelberg] = Heidelberg University, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg], and Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, Valence (chemistry), 010304 chemical physics, Scattering, Binding energy, General Physics and Astronomy, Photoionization, Photon energy, 010402 general chemistry, 01 natural sciences, Molecular physics, Spectral line, 0104 chemical sciences, Vibronic coupling, X-ray photoelectron spectroscopy, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physical and Theoretical Chemistry
Abstract

International audience; The influence of vibronic coupling on the outer valence ionic states of cis-dichloroethene has been investigated by recording photoelectron spectra over the excitation range 19–90 eV using plane polarized synchrotron radiation, for two polarization orientations. The photoelectron anisotropy parameters and electronic state branching ratios derived from these spectra have been compared to theoretical predictions obtained with the continuum multiple scattering approach. This comparison shows that the photoionization dynamics of the à 2B2, B̃ 2A1, C̃ 2A2, and D̃ 2B1 states, all of which are formed through the ejection of an electron from a nominally chlorine lone-pair orbital, exhibit distinct evidence of the Cooper minimum associated with the halogen atom. While retaining a high degree of atomic character, these orbital ionizations nevertheless display clear distinctions. Simulations, assuming the validity of the Born-Oppenheimer and the Franck-Condon approximations, of the X̃ 2B1, à 2B2, and D̃ 2B1 state photoelectron bands have allowed some of the vibrational structure observed in the experimental spectra to be assigned. The simulations provide a very satisfactory interpretation for the X̃ 2B1 state band but appear less successful for the à 2B2 and D̃ 2B1 states, with irregularities appearing in both. The B̃ 2A1 and C̃ 2A2 state photoelectron bands exhibit very diffuse and erratic profiles that cannot be reproduced at this level. Photoelectron anisotropy parameters, β, have been evaluated as a function of binding energy across the studied photon energy range. There is a clear step change in the β values of the à 2B2 band at the onset of the perturbed peak intensities, with β evidently adopting the value of the B̃ 2A1 band β. The D̃ 2B1 band β values also display an unexpected vibrational level dependence, contradicting Franck-Condon expectations. These various behaviors are inferred to be a consequence of vibronic coupling in this system

Published
2018

10. Rapid Photoinduced Charge Injection into Covalent Polyoxometalate\textendash Bodipy Conjugates

Author

Black, Fiona A., Jacquart, Aurélie, Toupalas, Georgios, Alves, Sandra, Proust, Anna, Clark, Ian P., Gibson, Elizabeth A., Izzet, Guillaume, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Institut Parisien de Chimie Moléculaire (IPCM), Chimie Moléculaire de Paris Centre (FR 2769), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Chimie Structurale Organique et Biologique (CSOB), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Chimie Moléculaire de Paris Centre (FR 2769), Edifices PolyMétalliques (E-POM), Central Laser Facility (CLF), STFC Rutherford Appleton Laboratory (RAL), and Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC)

Subjects
POLE 3, POLE 2, [CHIM]Chemical Sciences, E-POM, CSOB
Published
2018

11. Determination of accurate electron chiral asymmetries in fenchone and camphor in the VUV range: sensitivity to isomerism and enantiomeric purity

Author

Uwe J. Meierhenrich, Gustavo A. Garcia, Ivan Powis, Iuliia Myrgorodska, Vincent Wanie, Romain Géneaux, Samuel Beaulieu, Lipsa Nag, Valérie Blanchet, Laurent Nahon, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de Nice (ICN), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Attophysique (ATTO), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Spectrometer, Chemistry, Analytical chemistry, General Physics and Astronomy, Synchrotron radiation, Photoionization, Electron, Photoelectric effect, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Ion, 0103 physical sciences, Physical and Theoretical Chemistry, Enantiomer, 010306 general physics, Enantiomeric excess
Abstract

International audience; Photoelectron circular dichroism (PECD) manifests itself as an intense forward/backward asymmetry in the angular distribution of photoelectrons produced from randomly-oriented enantiomers by photoionization with circularly-polarized light (CPL). As a sensitive probe of both photoionization dynamics and of the chiral molecular potential, PECD attracts much interest especially with the recent performance of related experiments with visible and VUV laser sources. Here we report, by use of quasi-perfect CPL VUV synchrotron radiation and using a double imaging photoelectron/photoion coincidence (i2PEPICO) spectrometer, new and very accurate values of the corresponding asymmetries on showcase chiral isomers: camphor and fenchone. These data have additionally been normalized to the absolute enantiopurity of the sample as measured by a chromatographic technique. They can therefore be used as benchmarking data for new PECD experiments, as well as for theoretical models. In particular we found, especially for the outermost orbital of both molecules, a good agreement with CMS-Xα PECD modeling over the whole VUV range. We also report a spectacular sensitivity of PECD to isomerism for slow electrons, showing large and opposite asymmetries when comparing R-camphor to R-fenchone (respectively −10% and +16% around 10 eV). In the course of this study, we could also assess the analytical potential of PECD. Indeed, the accuracy of the data we provide are such that limited departure from perfect enantiopurity in the sample we purchased could be detected and estimated in excellent agreement with the analysis performed in parallel via a chromatographic technique, establishing a new standard of accuracy, in the ±1% range, for enantiomeric excess measurement via PECD. The i2PEPICO technique allows correlating PECD measurements to specific parent ion masses, which would allow its application to analysis of complex mixtures

Published
2016

12. 4-Arylbenzenesulfonamides as Human Carbonic Anhydrase Inhibitors (hCAIs): Synthesis by Pd Nanocatalyst-Mediated Suzuki–Miyaura Reaction, Enzyme Inhibition, and X-ray Crystallographic Studies

Author

Fabrizio Carta, Claudiu T. Supuran, Benedetta Cornelio, Marta Ferraroni, Mariangela Ceruso, Janos Sapi, Graham A. Rance, Antonella Fontana, Marie Laronze-Cochard, Andrei N. Khlobystov, Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Università degli studi 'G. d'Annunzio' Chieti-Pescara [Chieti-Pescara] (Ud'A), Dipartimento di Chimica ‘Ugo Schiff', Università degli Studi di Firenze, Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, UK (UON), and NEUROFARBA Department [Firenze, Italy]

Subjects
Models, Molecular, Gene isoform, Stereochemistry, [CHIM.THER]Chemical Sciences/Medicinal Chemistry, Crystallography, X-Ray, 01 natural sciences, Isozyme, Catalysis, Substrate Specificity, Adduct, Structure-Activity Relationship, chemistry.chemical_compound, Neoplasms, Carbonic anhydrase, Drug Discovery, Humans, Structure–activity relationship, Carbonic Anhydrase Inhibitors, Sulfonamides, biology, 010405 organic chemistry, Chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Aryl, Drug Design, Isoenzymes, Nanostructures, Palladium, Medicine (all), Molecular Medicine, Drug Discovery3003 Pharmaceutical Science, Lyase, 0104 chemical sciences, 010404 medicinal & biomolecular chemistry, Crystallography, biology.protein, Selectivity
Abstract

International audience; Benzenesulfonamides bearing various substituted (hetero)aryl rings in the para-position were prepared by palladium nanoparticle-catalyzed Suzuki–Miyaura cross-coupling reactions and evaluated as human carbonic anhydrase (hCA, EC 4.2.1.1) inhibitors against isoforms hCA I, II, IX, and XII. Most of the prepared sulfonamides showed low inhibition against hCA I isoform, whereas the other cytosolic isoenzyme, hCA II, was strongly affected. The major part of these new derivatives acted as potent inhibitors of the tumor-associated isoform hCA XII. An opposite trend was observed for phenyl, naphthyl, and various heteroaryl substituted benzenesulfonamides which displayed subnanomolar hCA IX inhibition while poorly inhibiting the other tumor-associated isoform hCA XII. The inhibition potency and influence of the partially restricted aryl–aryl bond rotation on the activity/selectivity were rationalized by means of X-ray crystallography of the adducts of hCA II with several 4-arylbenzenesulfonamides.

Published
2016

13. Two-Electron Reductive Carbonylation of Terminal Uranium(V) and Uranium(VI) Nitrides to Cyanate by Carbon Monoxide

Author

Alexander J. Blake, Christos E. Kefalidis, Laurent Maron, William Lewis, David M. King, Floriana Tuna, Jonathan McMaster, Stephen T. Liddle, Peter A. Cleaves, Eric J. L. McInnes, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), School of Chemistry and Photon Science Institute, University of Manchester [Manchester], Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
nitrides, Inorganic chemistry, chemistry.chemical_element, Ether, Carbonylation, carbonylation, Nitride, 010402 general chemistry, Medicinal chemistry, 01 natural sciences, 7. Clean energy, Catalysis, carbon monoxide, Nitrides, uranium, chemistry.chemical_compound, Nucleophile, cyanates, [CHIM]Chemical Sciences, Carbon monoxide, Cyanates, [PHYS]Physics [physics], 010405 organic chemistry, General Chemistry, General Medicine, Uranium, Cyanate, Communications, 0104 chemical sciences, chemistry, Azide
Abstract

International audience; Two‐electron reductive carbonylation of the uranium(VI) nitride [U(TrenTIPS)(N)] (2, TrenTIPS=N(CH2CH2NSiiPr3)3) with CO gave the uranium(IV) cyanate [U(TrenTIPS)(NCO)] (3). KC8 reduction of 3 resulted in cyanate dissociation to give [U(TrenTIPS)] (4) and KNCO, or cyanate retention in [U(TrenTIPS)(NCO)][K(B15C5)2] (5, B15C5=benzo‐15‐crown‐5 ether) with B15C5. Complexes 5 and 4 and KNCO were also prepared from CO and the uranium(V) nitride [{U(TrenTIPS)(N)K}2] (6), with or without B15C5, respectively. Complex 5 can be prepared directly from CO and [U(TrenTIPS)(N)][K(B15C5)2] (7). Notably, 7 reacts with CO much faster than 2. This unprecedented f‐block reactivity was modeled theoretically, revealing nucleophilic attack of the π* orbital of CO by the nitride with activation energy barriers of 24.7 and 11.3 kcal mol−1 for uranium(VI) and uranium(V), respectively. A remarkably simple two‐step, two‐electron cycle for the conversion of azide to nitride to cyanate using 4, NaN3 and CO is presented.

Published
2014
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14. The role of 5f-orbital participation in unexpected inversion of the σ-bond metathesis reactivity trend of triamidoamine thorium( iv ) and uranium( iv ) alkyls

Author

Christos E. Kefalidis, Laurent Maron, Jian Fang, Stephen T. Liddle, Alexander J. Blake, William Lewis, Benedict M. Gardner, Peter A. Cleaves, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Lanzhou University, Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)

Subjects
[PHYS]Physics [physics], 010405 organic chemistry, Thermal decomposition, Inorganic chemistry, Thorium, chemistry.chemical_element, Ionic bonding, General Chemistry, Uranium, 010402 general chemistry, Metathesis, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Salt metathesis reaction, Bibenzyl, [CHIM]Chemical Sciences, Reactivity (chemistry)
Abstract

International audience; We report on the role of 5f-orbital participation in the unexpected inversion of the s-bond metathesis reactivity trend of triamidoamine thorium(IV) and uranium(IV) alkyls. Reaction of KCH 2 Ph with [U(Tren TIPS)(I)] [2a, Tren TIPS ¼ N(CH 2 CH 2 NSiPr i 3) 3 3À ] gave the cyclometallate [U {N(CH 2 CH 2 NSiPr i 3) 2 (CH 2 CH 2 NSiPr i 2 C[H]MeCH 2)}] (3a) with the intermediate benzyl complex not observable. In contrast, when [Th(Tren TIPS)(I)] (2b) was treated with KCH 2 Ph, [Th(Tren TIPS)(CH 2 Ph)] (4) was isolated; which is notable as Tren N-silylalkyl metal alkyls tend to spontaneously cyclometallate. Thermolysis of 4 results in the extrusion of toluene and formation of the cyclometallate [Th {N(CH 2 CH 2 NSiPr i 3) 2 (CH 2 CH 2 NSiPr i 2 C[H]MeCH 2)}] (3b). This reactivity is the reverse of what would be predicted. Since the bonding of thorium is mainly electrostatic it would be predicted to undergo facile cyclometallation, whereas the more covalent uranium system might be expected to form an isolable benzyl intermediate. The thermolysis of 4 follows well-defined first order kinetics with an activation energy of 22.3 AE 0.1 kcal mol À1 , and Eyring analyses yields DH ‡ ¼ 21.7 AE 3.6 kcal mol À1 and DS ‡ ¼ À10.5 AE 3.1 cal K À1 mol À1 , which is consistent with a s-bond metathesis reaction. Computational examination of the reaction profile shows that the inversion of the reactivity trend can be attributed to the greater f-orbital participation of the bonding for uranium facilitating the s-bond metathesis transition state whereas for thorium the transition state is more ionic resulting in an isolable benzyl complex. The activation barriers are computed to be 19.0 and 22.2 kcal mol À1 for the uranium and thorium cases, respectively, and the latter agrees excellently with the experimental value. Reductive decomposition of "[U(Tren TIPS)(CH 2 Ph)]" to [U(Tren TIPS)] and bibenzyl followed by cyclometallation to give 3a with elimination of dihydrogen was found to be endergonic by 4 kcal mol À1 which rules out a redox-based cyclometallation route for uranium.

Published
2014

15. Simulation of Two-Dimensional Ultraviolet Spectroscopy of Amyloid Fibrils

Author

Shaul Mukamel, Jonathan D. Hirst, Cyril Falvo, Darius Abramavicius, Jun Jiang, Benjamin M. Bulheller, University of California [Irvine] (UCI), University of California, School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK., and School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Code (UMR, EA, ...)

Subjects
Circular dichroism, Protein Conformation, Amino Acid Motifs, Infrared spectroscopy, macromolecular substances, Molecular Dynamics Simulation, 010402 general chemistry, Fibril, 01 natural sciences, Article, Absorption, Molecular dynamics, Ultraviolet visible spectroscopy, Protein structure, Materials Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Amyloid beta-Peptides, 010405 organic chemistry, Chemistry, Circular Dichroism, Peptide Fragments, 0104 chemical sciences, Surfaces, Coatings and Films, Crystallography, Kinetics, Biophysics, Protein folding, Spectrophotometry, Ultraviolet
Abstract

Revealing the structure and aggregation mechanism of amyloid fibrils is essential for the treatment of over 20 diseases related to protein misfolding. Coherent two-dimensional (2D) infrared spectroscopy is a novel tool that provides a wealth of new insight into the structure and dynamics of biomolecular systems. Recently developed ultrafast laser sources are extending multidimensional spectroscopy into the ultraviolet (UV) region, and this opens up new opportunities for probing fibrils. In a simulation study, we show that 2DUV spectra of the backbone of a 32-residue β-amyloid (Aβ(9-40)) fibril associated with Alzheimer's disease and two intermediate prefibrillar structures carry characteristic signatures of fibril size and geometry that could be used to monitor its formation kinetics. The dependence of these signals on the fibril size and geometry is explored. We demonstrate that the dominant features of the β-amyloid fibril spectra are determined by intramolecular interactions within a single Aβ(9-40), and intermolecular interactions at the "external interface" have clear signatures in the fine details of these signals.

Published
2010

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