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  • L. Ben Haj Hassen, S. Dhifaoui, Y. Rousselin, V. Marvaud, C. Stern, C. E. Schulz, and H. Nasri, “New insights on the electronic, magnetic, electric and molecular structure of a bis-(4-cyanopyridine) iron(III) complex with the meso-tetrakis(4-methoxyphenyl)porphyrin”, Inorganica Chimica Acta, vol. 486, p. 675-683, Feb. 2019.
    Abstract: We have successfully synthesized and characterized a new low-spin iron(III) bis(4-cyanopyridine) complex with a meso-porphyrin substituted in the para positions of the phenyls by the methoxy group, namely the bis(4-cyanopyridine)[(meso-tetrakis(4-metoxyphenylporphyrinato)]iron(III) trifluoromethanesulfonate chlorobenzene monosolvate complex with the formula [FeIII(TMPP)(4-CNpy)2]SO3CF3.C6H5Cl (I). This species was characterized through ultraviolet–visible, Fourier-transform infrared and Mössbauer spectroscopy as well as by SQUID magnetometry, cyclic voltammetry, and X-ray crystallography. These characterizations indicated that our synthetic heme model is a low-spin (S = 1/2) coordination compound and especially shows that the structural, electronic and the magnetic properties of complex (I) are closely dominated by the presence of the methoxy σ-donor group at the para positions of the meso-porphyrin.
    Tags: Cyclic voltammetry, E-POM, Iron(III) porphyrin, Magnetic properties, X-ray Molecular structure.

  • J. Besnardiere, B. Ma, A. Torres-Pardo, G. Wallez, H. Kabbour, J. M. González-Calbet, H. J. Von Bardeleben, B. Fleury, V. Buissette, C. Sanchez, T. Le Mercier, S. Cassaignon, and D. Portehault, “Structure and electrochromism of two-dimensional octahedral molecular sieve h’-WO3”, Nature Communications, vol. 10, no. 1, p. 327, Jan. 2019.
    Abstract: Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h’-WO3, built of (WO6)6 tunnel cavities. h’-WO3 is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h’-H0.07WO3. Gentle heating results in h’-WO3 with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors.
    Tags: ERMMES, POLE 2.

  • A. Cartier, E. Levernier, V. Corcé, T. Fukuyama, A. - L. Dhimane, C. Ollivier, I. Ryu, and L. Fensterbank, “Carbonylation of Alkyl Radicals Derived from Organosilicates through Visible-Light Photoredox Catalysis”, Angewandte Chemie International Edition, vol. 58, no. 6, p. 1789-1793, 2019.
    Abstract: Primary, secondary, and tertiary alkyl radicals formed by the photocatalyzed oxidation of organosilicates underwent efficient carbonylation with carbon monoxide (CO) to give a variety of unsymmetrical ketones. This study introduces the possibility of radical carbonylation under a photooxidative regime.
    Tags: carbonylation, CHEMBIO, MACO, photocatalysis, POLE 1, POLE 3, radicals, silicates, three-component reactions.

  • F. Célerse, L. Lagardère, E. Derat, and J. - P. Piquemal, “Massively Parallel Implementation of Steered Molecular Dynamics in Tinker-HP: Comparisons of Polarizable and Non-Polarizable Simulations of Realistic Systems”, Journal of Chemical Theory and Computation, vol. 15, no. 6, p. 3694-3709, Jun. 2019.
    Abstract: Steered molecular dynamic (SMD) is a powerful technique able to accelerate rare event sampling in Molecular Dynamics (MD) simulations by applying an external force to a set of chosen atoms. Despite generating nonequilibrium simulations, SMD remains capable of reconstructing equilibrium properties such as the Potential of Mean Force (PMF). Of course, one would like to use all types of force fields (FF) ranging from classical ones to more advanced polarizable models using point induced dipoles and distributed multipoles such as AMOEBA. To enable such studies, the SMD methodology has been implemented in the framework of the massively parallel Tinker-HP software allowing for both long polarizable and non-polarizable MD simulations of large proteins. To validate this new implementation, we first compared the Tinker-HP SMD results to the literature. Tests have been performed on three different benchmark systems: the M–A deca-alanine (112 atoms), the ubiquitin (9737 atoms), and the CD2CD58 complex (97594 atoms). Non-polarizable (AMBER99, AMBER99SB, CHARMM22/CMAP, and OPLS–AA/L) and polarizable (AMOEBAPRO13 and AMOEBABIO18) force fields have been used. For each one of them, PMFs have been reconstructed and compared in terms of free energy barrier and hydrogen bonding fluctuations behavior over time. Using a SMD velocity of 0.01 Å/ps applied to a set of 20 trajectories, we show that polarizable and non-polarizable force fields do not always agree. As it could be anticipated, strong discrepancies are noticed between polarizable and non-polarizable models when considered in vacuum, whereas results are more comparable when a water environment is added. However, for the largest system, i.e., the CD2CD58 complex, strong differences related to the modeling of a salt bridge are noticed exhibiting some potential issues with classical FFs. Overall, such simulations highlight the importance of the inclusion of polarization effects as PMF free energy barriers computed with AMOEBA always decrease compared to non-polarizable force fields.
    Tags: MACO, POLE 1.
    Attachment Full Text PDF 3.9 Mb (source)

  • N. Daffé, J. - R. Jiménez, M. Studniarek, A. Benchohra, M. - A. Arrio, R. Lescouëzec, and J. Dreiser, “Direct Observation of Charge Transfer and Magnetism in Fe4Co4 Cyanide-Bridged Molecular Cubes”, The Journal of Physical Chemistry Letters, vol. 10, no. 8, p. 1799-1804, Apr. 2019.
    Abstract: We have studied the zero-dimensional cubane molecular correspondent of a Prussian blue analogue Cs–Fe4Co4 at low temperature and high magnetic field by means of L-edge X-ray absorption spectroscopy and X-ray magnetic circular dichroism. We probe the magnetic and electronic structures of Fe and Co separately upon light irradiation, which allows us to observe directly the electron transfer coupled to a spin transition phenomenon within the molecular cubes and to investigate the nature of the metastable photoexcited state. The magnetic moments in the photoexcited state are found to be M = 1.3μB (Mspin = 0.59μB with large orbital moment, Morbit = 0.74μB) for low-spin FeIII and M = 1.5μB (Mspin = 1.08μB with orbital moment, Morbit = 0.41μB) for high-spin CoII at 2 K and 6.8 T. From our results, we evidence that a strong antiferromagnetic coupling between the metal ions can be ruled out.
    Tags: ERMMES, POLE 2.

  • S. De, A. Flambard, D. Garnier, P. Herson, F. H. Köhler, A. Mondal, K. Costuas, B. Gillon, R. Lescouëzec, B. Le Guennic, and F. Gendron, “Probing the Local Magnetic Structure of the [FeIII(Tp)(CN)3]− Building Block Via Solid-State NMR Spectroscopy, Polarized Neutron Diffraction, and First-Principle Calculations”, Chemistry – A European Journal, vol. 25, no. 52, p. 12120-12136, 2019.
    Abstract: Abstract The local magnetic structure in the [FeIII(Tp)(CN)3]− building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutron diffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanido ligands: Spin-polarization on the carbon atoms and spin-delocalization on the nitrogen atoms. The results of our combined density functional theory (DFT) and multireference calculations were found in good agreement with the PND results and the experimental NMR chemical shifts. Moreover, the ab-initio calculations allowed us to connect the experimental spin-density map characterized by PND and the suggested distribution of the spin-density on the ligands observed by NMR spectroscopy. Interestingly, significant differences were observed between the pseudo-contact contributions of the chemical shifts obtained by theoretical calculations and the values derived from NMR spectroscopy using a simple point-dipole model. These discrepancies underline the limitation of the point-dipole model and the need for more elaborate approaches to break down the experimental pNMR chemical shifts into contact and pseudo-contact contributions.
    Tags: ERMMES, POLE 2.

  • N. Fischer-Durand, D. Lizinska, V. Guérineau, B. Rudolf, and M. Salmain, “‘Clickable’ cyclopentadienyl iron carbonyl complexes for bioorthogonal conjugation of mid-infrared labels to a model protein and PAMAM dendrimer”, Applied Organometallic Chemistry, vol. 33, no. 4, p. e4798, 2019.
    Abstract: Owing to the intrinsic limitations of the conventional bioconjugation methods involving native nucleophilic functions of proteins, we sought to develop alternative approaches to introduce metallocarbonyl infrared labels onto proteins on the basis of the [3?+?2] dipolar azide-alkyne cycloaddition (AAC). To this end, two cyclopentadienyl iron dicarbonyl (Fp) complexes carrying a terminal or a strained alkyne handle were synthesized. Their reactivity was examined towards a model protein and poly (amidoamine) (PAMAM) dendrimer, both carrying azido groups. While the copper (I)-catalysed azide-alkyne cycloaddition (CuAAC) proceeded smoothly with the terminal alkyne metallocarbonyl derivative, labelling by strain-promoted azide-alkyne cycloaddition (SPAAC) was less successful in terms of final coupling ratios. Infrared spectral characterization of the bioconjugates showed the presence of two bands in the 2000?cm?1 region, owing to the stretching vibration modes of the carbonyl ligands of the Fp entities.
    Tags: bioconjugation, CHEMBIO, copper (I)-catalysed azide-alkyne cycloaddition, infrared spectroscopy, metallocarbonyl complex, POLE 3, strain-promoted azide-alkyne cycloaddition.
    Note Note
    <p>doi: 10.1002/aoc.4798</p>

  • X. Frogneux, L. Hippolyte, D. Mercier, D. Portehault, C. Chanéac, C. Sanchez, P. Marcus, F. Ribot, L. Fensterbank, and S. Carenco, “Direct Synthesis of N-Heterocyclic Carbene-Stabilized Copper Nanoparticles from an N-Heterocyclic Carbene–Borane”, Chemistry – A European Journal, vol. 25, no. 49, p. 11481-11485, 2019.
    Abstract: N-Heterocyclic carbene (NHC)-stabilized copper nanoparticles (NPs) were synthesized from an NHC–borane adduct and mesitylcopper(I) under thermal conditions (refluxing toluene for 2.5 h). NPs with a size distribution of 11.6±1.8 nm were obtained. The interaction between Cu NPs and NHC ligands was probed by X-ray photoelectron spectroscopy, which showed covalent binding of the NHC to the surface of the NPs. Mechanistic studies suggested that NHC–borane plays two roles: contributing to the reduction of [CuMes]2 to release Cu0 species and providing NHC ligands to stabilize the copper NPs.
    Tags: carbene ligands, copper, MACO, nanoparticles, POLE 1, radical reactions, reaction mechanisms.
    Attachment Full Text PDF 853.3 kb (source)

  • F. Fus, Y. Yang, S. Lee, S. Top, M. Carriere, A. Bouron, A. Pacureanu, J. Da Silva, M. Salmain, A. Vessieres, P. Cloetens, G. Jaouen, and S. Bohic, “Intracellular localization of an osmocenyl-tamoxifen derivative in breast cancer cells revealed by synchrotron radiation X-ray fluorescence nanoimaging”, Angewandte Chemie, vol. 131, no. ja, p. 3499-3503, Jan. 2019.
    Abstract: We have recently developed a series of tamoxifen-like metallocifens of the group-8 metals (Fe, Ru and Os) with strong antiproliferative activity on the triple negative breast cancer cells (MDA-MB-231). This property, not observed for the organic analog 4-hydroxytamoxifen, has been associated with the unique redox behavior of metallocenic moieties, readily affording reactive quinone methides in cancer cells. To shed light on the mechanism of action of these molecules, synchrotron radiation X-ray fluorescence (SR-XRF) nanoimaging studies were performed on cells exposed to osmocenyl-tamoxifen (Oc-OH-Tam) to disclose its intracellular distribution using osmium as an intrinsic reporter. High resolution mapping of the lipophilic Oc-OH-Tam in cells, revealed its preferential accumulation in the endomembrane system encompassing endoplasmic reticulum, nuclear envelope and vesicular structures. This is consistent with the ability of the amino nitrogen chain of the compounds to be protonated at physiological pH and responsible for electrostatic interactions between Oc-OH-Tam and membranes. We propose a comprehensive scenario that provides new insight into the cellular behavior and activation of Oc-OH-Tam and advances the understanding of its mechanism of action.
    Tags: bioorganometallic chemistry, breast cancer cells, CHEMBIO, elemental tomography, osmium, POLE 3, synchrotron X-ray fluorescence.
    Note Note
    <p>doi: 10.1002/ange.201812336</p>

  • D. Garnier, A. Mondal, Y. Li, P. Herson, L. - M. Chamoreau, L. Toupet, M. Buron Le Cointe, E. M. B. Moos, F. Breher, and R. Lescouëzec, “Tetranuclear [FeII2FeIII2]2+ molecular switches: [FeII(bik)2(N–)2] spin-crossover complexes containing [FeIII(Tp)(CN)3]– metalloligands as N-donor”, Comptes Rendus Chimie, May 2019.
    Abstract: Three novel mixed valence cyanide-bridged {FeIII2FeII2} square complexes were obtained through the self-assembling of [FeIII(Tp)(CN)3]- or [FeIII(Tp*)(CN)3]− cyanido building blocks with the in situ formed [FeII(bik)2(S)2] complex (Tp = hydrotris (pyrazol-1-yl)borate, Tp* = hydrotris (3,5-dimethyl-pyrazol-1-yl)borate, bik = bis(1-methylimidazol-2-yl)ketone, S = solvent). The structures of these three complexes (2, 3 and 4) are reminiscent of that of our previously published square complex {[FeIII(Tp)(CN)3]2 [FeII(bik)2]2}·[FeIII(Tp)(CN)3]2·18H2O·4CH3OH (1). They consist of cyanide-bridged square dicationic complexes, ClO4− (2 and 3) or BF4− (4) counterions and solvate molecules. The FT-IR cyanide stretching vibrations observed at νCN ≈ 2145–60 cm−1 are typical of {FeIII–CN–FeII} moieties. The investigation of the magnetic properties of 2 reveals the occurrence of spin-crossover centered at T1/2 = 227 K. The χMT variation, ca. 7 cm3 mol−1 K, reflects the complete spin-state change occurring on both {FeII(bik)(–NC)2} moieties (–NC represents the cyanido building blocks). The Slichter–Drickamer model leads to a weak cooperativity factor, Γ = 1.6 kJ mol−1 (with Γ < 2RT1/2), which reflects the gradual spin-state change. This is in agreement with the molecular structure of 2, which does not present significant intermolecular interactions. The calculated enthalpy and entropy variations associated with the spin-state equilibrium are ΔH = 24 kJ mol−1 and ΔS = 105 J K−1 mol−1. In contrast, 3 and 4 show only partial spin-crossover in the accessible temperature range (2–400 K) as the T1/2 are shifted toward higher temperatures (ca. T1/2 > 400 K). Although no photomagnetic effect is observed for 3, compound 4 shows a moderate increase in the magnetization upon irradiation at low temperature. This phenomenon is ascribed to the light-induced excited spin-state trapping (LIESST) effect. Interestingly, the complex 2 also shows a remarkable LIESST effect, which is observed with different laser lights covering the visible and near-infrared range. The resulting χMT value obtained in the photoinduced state suggests the occurrence of a ferromagnetic interaction inside the {FeIII–CN–FeII} units. Résumé Trois nouveaux complexes carrés {FeIII2FeII2} à pont cyanure et à valence mixte ont été obtenus par auto-assemblage des précurseurs cyanurés [FeIII(Tp)(CN)3]− ou [FeIII(Tp*)(CN)3]− et du complexe cationique [FeII(bik)2(S)2] formé in situ (Tp = hydrotris (pyrazol-1-yl)borate, Tp* = hydrotris (3,5-dimethyl-pyrazol-1-yl)borate, bik = bis(1-methylimidazol-2-yl)cétone, S = solvant). Les structures de ces trois complexes (2, 3 et 4) sont similaires à celle du complexe {[FeIII(Tp)(CN)3]2[FeII(bik)2]2}[FeIII(Tp)(CN)3]2·18H2O·4CH3OH (1) préalablement publié. Elles sont constituées de complexes carrés dicationiques à pont cyanure, de contre-ions ClO4− (2 and 3) ou BF4− (4) et de molécules de solvant. Les vibrations d’élongation des cyanures, observée en spectroscopie IR à νCN ≈ 2145–60 cm−1, sont caractéristiques d'unités {FeIII–CN–FeII}. L’étude des propriétés magnétiques de 2 révèle un équilibre de spin centré à T1/2 = 227 K. La variation du produit χMT, ca. 7 cm3 mol−1 K, traduit une conversion de spin complète sur chacune des unités {FeII(bik)(–NC)2} du carré (–NC représente le complexe précurseur cyanuré). L'analyse des données par le modèle de Slichter–Drickamer conduit à un faible facteur de coopérativité, Γ = 1.6 kJ mol−1 K (with Γ < 2RT1/2), en accord avec un changement d’état de spin graduel. Ces données sont en accord avec la structure de 2 qui ne montre pas d'interactions intermoléculaires notables. Les valeurs des variations d'enthalpie et d'entropie associées à la conversion de spin sont ΔH = 24 kJ mol−1 et ΔS = 105 J K−1 mol−1. Au contraire de 2, les composés 3 and 4 présentent seulement une conversion de spin partielle dans le domaine de température exploré (2–400 K), avec des valeurs T1/2 déplacées vers les hautes températures (ca. T1/2 > 400 K). Tandis qu'on n'observe pas d'effet photomagnétique pour 3 et seulement un faible effet dans 4, le composé 2 présente une forte augmentation de son aimantation sous irradiation à basse température. Cet effet est dû au piégeage photo-induit d'un état excité de spin (effet « LIESST », Light-Induced Excited Spin-State Trapping). Il est observé avec différentes sources laser couvrant le spectre visible et le proche infrarouge. Les valeurs de χMT obtenues dans l’état photo-induit suggèrent la présence d'une interaction ferromagnétique au sein de la paire {FeIII–CN–FeII}.
    Tags: ERMMES, POLE 2.

  • M. Girardi, D. Platzer, S. Griveau, F. Bedioui, S. Alves, A. Proust, and S. Blanchard, “Assessing the Electrocatalytic Properties of the Cp*RhIII2+-Polyoxometalate Derivative [H2PW11O39RhIIICp*(OH2)]3– towards CO2 Reduction”, European Journal of Inorganic Chemistry, vol. 2019, no. 3-4, p. 387-393, 2019.
    Abstract: Storage of electricity produced intermittently by renewable energy sources is a societal issue. Besides the use of batteries and supercapacitors, conversion of excess electricity into chemical energy is also actively investigated. The conversion of CO2 to fuel or fuel precursors is an option that requires the use of a catalyst to overcome the high activation energy barrier. Of molecular catalysts, metal complexes with polypyridyl ligands are well represented, among which the [Cp*Rh(bpy)Cl]+ and [M(bpy)(CO)3X] (M = Re, Mn) complexes. As redox non-innocent ligand, the bipyridine ligand is generally involved in the reduction mechanisms. It is thus tempting to replace it by other redox non-innocent ligands such as vacant polyoxometalates (POMs). We have thus prepared [α-H2PW11O39RhIIICp*(OH2)]3– which is closely related to [Cp*RhIII(bpy)Cl]+ by substitution of the monovacant [PW11O39]7– Keggin-type POM for the bipyridine ligand. Its activity towards CO2 reduction has been assessed in acetonitrile in the presence of water. Compared to [Cp*Rh(bpy)Cl]+ that produces formate selectively over CO and H2, the POM derived catalyst favors proton reduction over CO2 reduction.
    Tags: Carbon dioxide fixation, CSOB, E-POM, Non-innocent ligands, Polyoxometalates, Redox chemistry.
    Attachment Full Text PDF 974.1 kb (source)

  • L. Guyon, E. Lepeltier, J. - C. Gimel, B. Calvignac, F. Franconi, N. Lautram, A. Dupont, C. Bourgaux, P. Pigeon, P. Saulnier, G. Jaouen, and C. Passirani, “Importance of Combining Advanced Particle Size Analysis Techniques To Characterize Cell-Penetrating Peptide–Ferrocifen Self-Assemblies”, The Journal of Physical Chemistry Letters, p. 6613-6620, Oct. 2019.
    Tags: CHEMBIO, POLE 3.
    Note Note
    <p>doi: 10.1021/acs.jpclett.9b01493</p>

  • A. Harbi, H. Moutaabbid, Y. Li, C. Renero-Lecuna, M. Fialin, Y. Le Godec, S. Benmokhtar, and M. Moutaabbid, “The effect of cation disorder on magnetic properties of new double perovskites La2NixCo1-xMnO6 (x = 0.2–0.8)”, Journal of Alloys and Compounds, vol. 778, p. 105-114, Mar. 2019.
    Abstract: Solid solutions of new double perovskite oxides La2NixCo1-xMnO6 (x = 0.2, 0.25, 0.5, 0.75, 0.8) were synthesized by solid-state reaction method. The X-ray powder diffraction data show that all the compounds crystallize in the monoclinic structure with space group P21/n at room temperature. The elementary composition of the powders was determined by the electron Probe Microanalysis. Raman and IR spectra show strong bands at (520, 650 cm−1) and (426, 600 cm−1) respectively, attributed to the stretching vibration of Ni/Co-O and Mn-O bonds in the structure. The magnetic studies for all the compounds have been performed in both DC and AC magnetic fields in the temperature range from 2 to 300 K. All samples exhibit a main paramagnetic to ferromagnetic (PM-FM) transition between 232 K and 260 K, and their Curie temperature increases rapidly with increasing x values. Three samples with x = 0.2, 0.25 and 0.5 respectively display also a secondary PM-FM transition between 200 K and 208 K. The thermal variation of out of phase component of AC susceptibility presents also frequency-dependent transitions between 65 K and 110 K unfolding the existence of super-paramagnetic mono-domains in all samples. The band gap energy has been calculated and revealing semiconductor behavior for all samples.
    Tags: ERMMES, POLE 2.

  • N. Illy, V. Corcé, J. Zimbron, V. Molinié, M. Labourel, G. Tresset, J. Degrouard, M. Salmain, and P. Guégan, “pH-Sensitive Poly(ethylene glycol)/Poly(ethoxyethyl glycidyl ether) Block Copolymers: Synthesis, Characterization, Encapsulation, and Delivery of a Hydrophobic Drug”, Macromolecular Chemistry and Physics, vol. 220, no. 16, p. 1900210, 2019.
    Abstract: Abstract Curcumin is a natural polyphenolic compound known for its numerous pharmacological properties. However, its low water solubility and instability at neutral pH are serious drawbacks preventing its use as an oral drug. Well-defined amphiphilic poly(ethylene glycol)-block-poly(ethoxyethyl glycidyl ether) (PEG-b-PEEGE) block copolymers carrying acid-labile acetal groups are synthesized by anionic ring-opening polymerization and investigated as potential pH-sensitive nano-carriers for delivery of curcumin to cancer cells. The nanoparticles, resulting from copolymer self-assembly in aqueous media, are characterized by dynamic light scattering and cryo-transmission electron microscopy. The nanoparticles? stabilities are evaluated in three different phosphate buffers (pH = 7.2, 6.4, and 5.3). The stability decreases at lower pH and a complete disappearance of the nanoparticles is noticed after 4 days at pH 5.3. Curcumin is encapsulated in hydrophobic core of mPEG40-b-PEEGE25 nanoparticles allowing significant enhancements of curcumin solubility in water and lifetime at neutral pH. In vitro curcumin release is studied at different pH by UV-spectroscopy and high-performance liquid chromatography (HPLC). The cytotoxicity of curcumin and curcumin encapsulated in micelles is evaluated by cell viability 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on MDA-MB-231 human breast cancer cells.
    Tags: amphiphilic polyethers, anionic-ring opening polymerization, CHEMBIO, curcumin encapsulation, pH-sensitive copolymers, POLE 3, POLE 4, POLYMERES, self-assembly.
    Note Note
    <p>doi: 10.1002/macp.201900210</p>

  • “15 Silicates in Photocatalysis”, in Photocatalysis in Organic Synthesis, 2019th ed., B. König, Eds. Stuttgart: Georg Thieme Verlag, 2019.

  • C. M. Kronfel, C. V. Hernandez, J. P. Frick, L. S. Hernandez, A. Gutu, J. A. Karty, M. N. Boutaghou, D. M. Kehoe, R. B. Cole, and W. M. Schluchter, “CpeF is the bilin lyase that ligates the doubly linked phycoerythrobilin on β-phycoerythrin in the cyanobacterium <i>Fremyella diplosiphon</i>”, Journal of Biological Chemistry, p. jbc.RA118.007221, Jan. 2019.

  • S. H. Z. Lee, F. Chau, S. Top, G. Jaouen, A. Vessières, E. Labbé, and O. Buriez, “New mechanistic insights into osmium-based tamoxifen derivatives”, Electrochimica Acta, vol. 302, p. 130-136, 2019.
    Abstract: The electrochemical behavior of osmociphenol (3, Oc-OH), an organometallic osmium-based anticancer drug candidate, has been investigated by cyclic voltammetry in the absence and presence of lutidine used as a base model. Osmociphenol exhibited spontaneous deprotonation of the phenol function upon oxidation of the osmocene moiety due to its high acidity. In the presence of lutidine, a base-dependent and different electrochemical behavior was observed at low scan rates indicating a second oxidation step leading to the corresponding cationic quinone methide precursor (3b+). However, compared to ruthenocene derivatives, the stability of 3b+ prevented its conversion into quinone methide as the final and stable complex. Despite differences in their oxidative processes, osmociphenol and ruthenociphenol derivatives exhibit similar biological activities.
    Tags: Anti-cancer, Bioorganometallic, CHEMBIO, Cyclic voltammetry, Osmium, POLE 3, Tamoxifen.

  • L. Lempenauer, G. Lemière, and E. Duñach, “Cyclisation Reactions Involving Alkyl Enol Ethers”, Advanced Synthesis & Catalysis, 2019.
    Abstract: Enol ethers are a fascinating product class and valuable building blocks with versatile reactivities and synthetic applications. With the emergence of silyl enol ethers, the chemistry of simple alkyl enol ethers has received less attention and targeted reviews of their chemistry are scarce. Especially intramolecular reactions under participation of an enol ether function have never been specifically surveyed. The construction of cyclic scaffolds is arguably one of the most important and challenging tasks of the organic chemist and intramolecular cyclisations represent the most straight-forward tool to achieve this goal. The potential of enol ether-containing substrates to form oxygenated carbo- and heterocycles is obvious. The purpose of this review is to discuss their particular reactivity and to direct the reader's attention to how their unique properties have been harnessed by organic chemists for the construction of rings.
    Tags: catalysis, cyclisations, enol ethers, intramolecular reactions, Lewis acids, MACO, POLE 1.
    Attachment Full Text PDF 983.3 kb (source)

  • D. Lesage, S. Mezzache, Y. Gimbert, H. Dossmann, and J. - C. Tabet, “Extended kinetic method and RRKM modeling to reinvestigate proline’s proton affinity and approach the meaning of effective temperature”, European Journal of Mass Spectrometry, p. 146906671882205, Jan. 2019.

  • E. Levernier, V. Corcé, L. - M. Rakotoarison, A. Smith, M. Zhang, S. Ognier, M. Tatoulian, C. Ollivier, and L. Fensterbank, “Cross coupling of alkylsilicates with acyl chlorides via photoredox/nickel dual catalysis: a new synthesis method for ketones”, Organic Chemistry Frontiers, vol. 6, no. 9, p. 1378-1382, 2019.
    Abstract: Photoredox/nickel dual catalysis using easily oxidized bis-catecholato hypercoordinated silicon derivatives as radical sources and acyl chlorides as electrophiles allows a new method of formation of dialkyl and alkyl-aryl ketones as well as dibenzyl ketones which are less easily accessed. Flow chemistry can be used.
    Tags: CHEMBIO, MACO, POLE 1, POLE 3.

  • Y. Liu, J. Oble, and G. Poli, “Switchable selectivity in Pd-catalyzed [3 + 2] annulations of γ-oxy-2-cycloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation”, Beilstein Journal of Organic Chemistry, vol. 15, no. 1, p. 1107-1115, May 2019.
    Abstract: Beilstein Journal of Organic Chemistry
    Tags: POLE 1, ROCS.
    Attachment Full Text PDF 559.7 kb (source)

  • O. Makrygenni, D. Brouri, A. Proust, F. Launay, and R. Villanneau, “Immobilization of polyoxometalate hybrid catalysts onto mesoporous silica supports using phenylene diisothiocyanate as a cross-linking agent”, Microporous and Mesoporous Materials, vol. 278, p. 314-321, Apr. 2019.
    Abstract: The hybrid derivative of heteropolytungstate bearing two aniline groups, namely (nBu4N)3[NaHPW9O34{As(O)C6H4NH2}2], was post-functionalized in the presence of 1,4-phenylene diisothiocyanate (PDITC). The resulting molecular moiety was characterized by IR, 1H and 31P NMR spectroscopy. In a second step, this post-functionalized hybrid of polyoxometalate was covalently grafted onto the surface of an amino-functionalized SBA-15 silica by means of the formation of thiourea bonds. This simple and efficient strategy of immobilization did not require the use of a coupling agent and was performed in mild reaction conditions. Various physicochemical techniques (13C and 31P CPMAS NMR spectroscopies, XPS, XRF, HR-TEM microscopy and N2 sorption) contributed to the full characterization of the supported catalyst. In addition HR-TEM was found to be an essential technique for the identification of the polyoxometalate units inside the pores of SBA-15. Finally, the catalytic performances of the supported polyoxometalates were evaluated in the epoxidation of cyclooctene with aqueous H2O2 in acetonitrile at 50 °C.

    rong> Anchored homogeneous catalysts, E-POM, Epoxidation catalysis, Functionalized mesoporous silica materials, Polyoxometalate hybrids.

  • C. Medena, F. Calogero, Q. Lemoine, C. Aubert, E. Derat, L. Fensterbank, G. Gontard, O. Khaled, N. Vanthuyne, J. Moussa, C. Ollivier, M. Petit, and M. Barbazanges, “A HELIXOL-Derived Bisphosphinite Ligand: Synthesis and Application in Gold-Catalyzed Enynes Cycloisomerization”, European Journal of Organic Chemistry, vol. 2019, no. 11, p. 2129-2137, 2019.
    Abstract: The synthesis, optical resolution through derivatization, characterization, and utilization of a new helical bis(phosphinite gold) complex derived from HELIXOL are described. By using an efficient cobalt catalyst, neither irradiation nor high catalytic loading was required to access the helicene of interest. The latter was phosphorylated to afford a new chiral ligand that was studied. Especially, treatment with AuCl(SMe2) gives a dinuclear gold complex that was used in cycloisomerization reactions.
    Tags: ARC, Chirality, Enyne Cycloisomerization, Helicene, Homogeneous catalysis, MACO, Phosphinite, POLE 1.
    Attachment Full Text PDF 1.5 Mb (source)

  • F. Medici, J. Maury, G. Lemière, and L. Fensterbank, “Interaction between Spirosilanes and Lewis Bases: from Coordination to Frustration”, Chemistry – A European Journal, vol. 25, no. 40, p. 9438-9442, 2019.
    Abstract: In this work, the interaction between Lewis bases, especially N-heterocyclic carbenes (NHCs), and hindered neutral silicon derivatives featuring high Lewis acidity is described. The formation of normal and abnormal Lewis adducts could be controlled by varying the acidity of the corresponding tetravalent spiro organosilane. Some DFT calculations permitted to gain insight into the thermodynamics of the NHC–spirosilane interaction featuring various NHCs differing in size and σ-donor capacity. Spirosilanes are introduced as new Lewis partners in frustrated Lewis pair (FLP) chemistry and some FLP-type reactivities are presented, in particular the activation of formaldehyde that could occur with both hindered NHCs and phosphines.
    Tags: frustrated Lewis pairs, Lewis acid, MACO, pentavalent silicon, spirosilanes.

  • T. Neva, T. Carmona, J. M. Benito, C. Przybylski, C. Ortiz Mellet, F. Mendicuti, and J. M. García Fernández, “Dynamic Control of the Self-Assembling Properties of Cyclodextrins by the Interplay of Aromatic and Host-Guest Interactions”, Frontiers in Chemistry, vol. 7, p. 72, 2019.
    Abstract: The presence of a doubly-linked naphthylene clip at the O-2I and O-3II positions in the secondary ring of -cyclodextrin (CD) derivatives promoted their self-assembly into head-to-head supramolecular dimers in which the aromatic modules act either as cavity extension walls (if the naphthalene moiety is 1,8-disubstituted) or as folding screens that separate the individual CD units (if 2,3-disubstituted). Dimer architecture is governed by the conformational properties of the monomer constituents, as determined by NMR, fluorescence, circular dichroism and computational techniques. In a second supramolecular organization level, the topology of the assembly directs host-guest interactions and, reciprocally, guest inclusion impacts the stability of the supramolecular edifice. Thus, inclusion of adamantane carboxylate, a well-known CD cavity-fitting guest, was found to either preserve the dimeric arrangement, leading to multicomponent species, or elicit dimer disruption. The ensemble of results highlights the potential of the approach to program self-organization and external stimuli responsiveness of CD devices in a controlled manner while keeping full diastereomeric purity.
    Tags: CSOB, POLE 3.

  • M. Okubo, J. Long, D. R. Talham, and R. Lescouëzec, “Solid-state electrochemistry of metal cyanides”, Comptes Rendus Chimie, vol. 22, no. 6, p. 483 - 489, 2019.
    Abstract: Efficient energy storage in the form of batteries contributes to building sustainable society. As advanced batteries need positive electrode materials capable of larger capacity, higher voltage, and lower cost, it is important to search for novel electrode materials. Among various inorganic/organic materials, cyanido-bridged coordination compounds are promising candidates for battery electrodes due to their ability to undergo solid-state redox reaction associated with ion (de)intercalation. In this review, recent results about the thermodynamic and kinetic aspects of the solid-state electrochemistry of cyanido-bridged coordination compounds are summarized, providing a fundamental basis toward developing cyanide electrodes for advanced batteries. Résumé Le stockage de l’énergie dans des batteries performantes est un élément clé pour le développement des énergies renouvelables et d'un modèle de société durable. Un des défis pour construire de nouvelles batteries plus performantes est le développement de matériaux d'intercalation pour cathode présentant de plus grandes capacités, de plus grands voltages et des coûts réduits. Parmi les divers matériaux organiques et inorganiques explorés, les polymères de coordination à pont cyanure sont des candidats prometteurs. Ceux ci peuvent s'oxyder et se réduire à l’état solide en (dés)intercalant des ions. Dans cette revue, quelques résultats récents sur les aspects thermodynamiques et cinétiques des propriétés électrochimiques des polymères de coordination à pont cyanure sont résumés, démontrant leur potentiel intérêt comme életcrodes dans de nouvelles batteries.
    Tags: ERMMES, POLE 2.
    Note Note
    <p>Forty years of exchange interactions on the occasion of the 75th birthday of Michel Verdaguer</p>

  • W. X. C. Oliveira, W. D. do Pim, C. B. Pinheiro, Y. Journaux, M. Julve, and C. L. M. Pereira, “Monitoring the hydrogen bond net configuration and the dimensionality of aniline and phenyloxamate by adding 1H-pyrazole and isoxazole as substituents for molecular self-recognition”, CrystEngComm, vol. 21, no. 17, p. 2818-2833, Apr. 2019.
    Abstract: This work describes the synthesis and characterization of a new class of oxamic acid derivatives containing pyrazole and isoxazole as substituents to investigate their ability to form hydrogen bonds aiming at applying them in crystal engineering and molecular self-recognition. In this respect, we report a new synthesis of 2-(4-nitrophenyl)-1,3-propanedial (1) in high yield using SOCl2 as a chlorinating agent. The new oxamic esters 4-(1H-pyrazol-4-yl)phenylene-N-(ethyloxamate) (2d) and 4-(1,2-oxazol-4-yl)phenylene-N-(ethyloxamate) (3d) were prepared from 1. The synthetic route consists of the cyclisation of 1 either with hydrazine to afford 4-(-aminophenyl)-1H-pyrazole (2a) or with hydroxylamine to obtain the isoxazole-based molecule 4-(4-nitrophenyl)-1,2-oxazole (3a). The reduction of 2a and 3a was carried out in an acidic/tin solution to yield 4-(4-ammoniophenyl)-1H-pyrazol-2-ium trichlorostannate(II) chloride monohydrate (2b) and 4-(4-ammoniophenyl)-1,2-oxazole hexachlorostannate(IV) (3b). Basic extraction of 3b provided 4-(4-aminophenyl)-1,2-oxazole (3c). The reduction of 2a to 4-(4-aminophenyl)-1H-pyrazole (2c) was achieved by means of hydrazine associated with supported palladium on carbon. The condensation of 2c and 3c with ethyl chlorooxoacetate delivers oxamic esters 2d and 3d. In n-tetrabutylammonium hydroxide solution 2d is fully hydrolyzed, obtaining the n-tetrabutylammonium salt of 4-(1H-pyrazole-4-yl)phenylene-N-oxamate as a hemihydrate (2e). The low stability of isoxazole molecules in basic solutions was proved by crystallizing the n-tetrabutylammonium salt of 1-cyano-1-(4-nitrophenyl)-2-oxoethanide (3f) (obtained by cleavage of 3d with n-Bu4NOH) and preparing its conjugated acid 2-(4-nitrophenyl-3-oxopropanenitrile (3e). The structures of 2b, 3b, 3d and 2e were solved by single crystal X-ray diffraction techniques. The analysis of their crystal packing reveals hydrogen bond features compatible for all compounds as well as some differences depending on the pH of the crystallization solution and the presence or absence of the oxamate group due to the increase of hydrogen bond donors and acceptors.
    Tags: ERMMES, POLE 2.
    Attachment Full Text PDF 3.1 Mb (source)

  • C. Przybylski, V. Bonnet, and R. R. Vivès, “A microscale double labelling of GAG oligosaccharides compatible with enzymatic treatment and mass spectrometry”, Chemical Communications, vol. 55, no. 29, p. 4182-4185, 2019.

  • C. Przybylski, H. Ramoul, V. Bonnet, M. Abad, and N. Jarroux, “Harnessing Polyisobutylene by Rotaxanation with γ-Cyclodextrin: Opportunities for Making Smart Molecular Necklaces”, Macromolecular Chemistry and Physics, vol. 220, no. 5, p. 1800502, Mar. 2019.
    Abstract: Abstract A new type of polyrotaxane based on the threading of ?-cyclodextrins (?-CDs) along a highly hydrophobic polymer, polyisobutylene (PIB), is successfully prepared and finely characterized. The used radical coupling associated with tuned reaction time and temperature leads to a fast and controlled necklace synthesis with low reagent consumption. Synthesis exhibits appealing conversion and threading rates with almost 100% and 62?73%, respectively. A combination of well-established SEC and NMR techniques, with a more forefront MALDI-TOF MS approach, provides details on the original PIB and the resulting polyrotaxanes (M w, M n, PDI, and average number of ?-CD threaded). Interestingly, tetramethylguanidinium-2-(4-hydroxyphenylazo)benzoate in DMF for MALDI analysis is revealed as a suitable matrix to overcome solubility troubles widely observed with PIB. Moreover, rotaxanation appears as an alternative to the grafting of polar groups to modify/handle hydrophobic polymers. Such an approach offers new opportunities to achieve the synthesis, with unambiguous evidence, of new supramolecular necklaces based on highly hydrophobic polymers.
    Tags: CSOB, cyclodextrins, mass spectrometry, POLE 3, polyisobutylene, polyrotaxane, radical coupling.
    Note Note
    <p>doi: 10.1002/macp.201800502</p>
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  • J. M. J. M. Ravasco, C. M. Monteiro, F. Siopa, A. F. Trindade, J. Oble, G. Poli, S. P. Simeonov, and C. A. M. Afonso, “Creating Diversity from Biomass: A Tandem Bio/Metal-Catalysis towards Chemoselective Synthesis of Densely Substituted Furans”, ChemSusChem, vol. 12, no. 20, p. 4629-4635, 2019.
    Abstract: A new chemoselective (enzymatic desymmetrization/Ru-catalyzed C−H activation) sequence to obtain differently substituted furans from the largely available 2,5-furandicarboxylic acid (FDCA) was developed. Series of di- and trisubstituted furans were prepared in very good yields and excellent chemoselectivity. This study discloses a new approach towards valorization of the furanics platform through the use of FDCA as a stable intermediate, thus circumventing the chemical instability of the parent 5-hydroxymethylfurfural.
    Tags: POLE 1, ROCS.
    Attachment Full Text PDF 1.8 Mb (source)

  • M. Salmain, N. Fischer-Durand, and B. Rudolf, “Bioorthogonal Conjugation of Transition Organometallic Complexes to Peptides and Proteins: Strategies and Applications”, European Journal of Inorganic Chemistry, Oct. 2019.
    Abstract: The advent of bioorthogonal chemistry has revolutionized the common practices in protein bioconjugation and contributed to a large extent to the development of chemical biology, a discipline aimed at studying biological/biochemical processes/events in their natural setting (living cells, whole organisms) using dedicated chemical tools. This minireview intends to provide an up-to-date overview on the various bioorthogonal strategies implemented for the conjugation of transition organometallic entities to peptides, peptide nucleic acids and proteins with a focus on targeted applications, i.e. fluorescence- or radio-labeling for imaging, controlled delivery of therapeutic agents and bioanalysis.
    Tags: CHEMBIO, Click chemistry, Cycloaddition, Ferrocene, Manganese, Peptide nucleic acids, POLE 3.
    Note Note
    <p>doi: 10.1002/ejic.201900810</p>

  • I. Seffouh, C. Przybylski, A. Seffouh, R. El Masri, R. R. Vivès, F. Gonnet, and R. Daniel, “Mass spectrometry analysis of the human endosulfatase Hsulf-2”, Biochemistry and Biophysics Reports, vol. 18, p. 100617, 2019.
    Abstract: The human 6-O-endosulfatases HSulf-1 and -2 catalyze the region-selective hydrolysis of the 6-O-sulfate group of the glucosamine residues within sulfated domains of heparan sulfate, thereby ensuring a unique and original post-biosynthetic modification of the cell surface proteoglycans. While numerous studies point out the role of HSulf-2 in crucial physiological processes as well as in pathological conditions particularly in cancer, its structural organization in two chains and its functional properties remain poorly understood. In this study, we report the first characterization by mass spectrometry (MS) of HSulf-2. An average molecular weight of 133,115 Da was determined for the whole enzyme by MALDI-TOF MS, i.e. higher than the naked amino acid backbone (98,170 Da), highlighting a significant contribution of post-translational modifications. The HSulf-2 protein sequence was determined by Nano-LC-MS/MS, leading to 63% coverage and indicating at least four N-glycosylation sites at Asn 108, 147, 174 and 217. These results provide a platform for further structural investigations of the HSulf enzymes, aiming at deciphering the role of each chain in the substrate binding and specificities and in the catalytic activities.
    Tags: 6--Endosulfatase, CSOB, Formylglycine, Heparan sulfate, HSulf-2, Mass spectrometry, POLE 3, Sulfatase.

  • C. Sonnendecker, S. Thürmann, C. Przybylski, F. D. Zitzmann, N. Heinke, Y. Krauke, K. Monks, A. A. Robitzki, D. Belder, and W. Zimmermann, “Large‐Ring Cyclodextrins as Chiral Selectors for Enantiomeric Pharmaceuticals”, Angewandte Chemie International Edition, 2019.

  • O. Stetsiuk, V. Synytsia, S. R. Petrusenko, V. N. Kokozay, A. El-Ghayoury, J. Cano, F. Lloret, M. Julve, B. Fleury, and N. Avarvari, “Co-existence of ferro- and antiferromagnetic interactions in a hexanuclear mixed-valence CoIII2MnII2MnIV2 cluster sustained by a multidentate Schiff base ligand”, Dalton Transactions, vol. 48, no. 31, p. 11862-11871, 2019.
    Abstract: The successful utilization of the “direct synthesis” approach yielded the unprecedented hexanuclear complex of formula [Co2MnII2MnIV2(L1)4Cl2(μ3-O)2(dmf)4]·2dmf (1) (H3L is the Schiff base derived from the condensation of salicylaldehyde and 3-aminopropane-1,2-diol). Single crystal X-ray analysis revealed that 1 crystallizes in the monoclinic system P21/c and it contains a rare mixed-valence CoIII2MnII2MnIV2(μ2-O)8(μ3-O)2 core where all metal ions are linked through the phenolato and alkoxo groups of the L3− ligand. Besides the charge balance resulting from the X-ray structure, the oxidation state of the metal ions has been confirmed by XPS spectroscopy. Cryomagnetic studies indicate the coexistence of ferro- (MnIV–MnII, J2 = +1.10(3) cm−1, J3 = +2.19(3) cm−1; MnII–MnII, j = +0.283(3) cm−1) and antiferromagnetic interactions (MnIV–MnIV, J1 = −17.31(4) cm−1), with the six-coordinate CoIII ions being diamagnetic. DFT type calculations were carried out to substantiate these values. The energy diagram for the different spin states using the best-fit parameters shows the occurrence of six low-lying spin states (S = 0–5) which are close in energy but clearly separated from the remaining ones, with the ground spin state being S = 5. Complex 1 is found to be the first example where weak ferromagnetic exchange between MnII ions through the long –O–MnIV–O– pathway takes place.
    Tags: ERMMES, POLE 2.

  • F. Tonolo, M. Salmain, V. Scalcon, S. TOP, P. Pigeon, A. Folda, B. Caron, M. J. McGlinchey, R. - A. Toillon, A. Bindoli, G. Jaouen, A. Vessieres, and M. P. Rigobello, “Small Structural Differences Between Two Ferrocenyl Diphenols Determine Large Discrepancies of Reactivity and Biological Effects”, ChemMedChem, no. ja, Sep. 2019.
    Abstract: Ferrocenyl diphenol complexes 1, [1,1-bis(4?-hydroxyphenyl)-2-ferrocenyl-but-1-ene], and Z-2, [1,2-bis(4?-hydroxyphenyl)-1-ferrocenyl-but-1-ene], differing by the relative position of the two phenolic substituents, display dramatically different antiproliferative activities on cancer cells (1 being by far more cytotoxic than 2). In this paper our goal is to decipher the origin of this difference by comparing their reactivity and biological behaviour. In terms of common behaviour we found that 1 and 2 are both very efficient inhibitors of thioredoxin reductase (TrxR) in vitro after oxidation by the HRP/H2O2 system. However, as 1 is only a moderate inhibitor of TrxR in MDA-MB-231 cells, TrxR is probably not a major target responsible for the cytotoxicity of 1. In terms of difference we noted that 1 induces a significant redox imbalance characterized by lipid peroxidation and thiol oxidation and a moderate decrease of the mitochondrial membrane potential in breast cancer cells while 2 has almost no effect. These results underline the importance of the trans configuration in the ferrocenyl /double bond / phenol motif, which is present in 1 but not in Z-2 that exists only in a cis configuration.
    Tags: Bioorganometallic chemistry, cancer, CHEMBIO, iron, lipid peroxidation, POLE 3, Thioredoxin Reductase.
    Note Note
    <p>doi: 10.1002/cmdc.201900430</p>

  • A. Vivien, M. Guillaumont, L. Meziane, C. Salzemann, C. Aubert, S. Halbert, H. Gérard, M. Petit, and C. Petit, “Role of Oleylamine Revisited: An Original Disproportionation Route to Monodispersed Cobalt and Nickel Nanocrystals”, Chemistry of Materials, vol. 31, no. 3, p. 960-968, Feb. 2019.
    Abstract: Herein is highlighted an original disproportionation mechanism for the formation of hexagonal closed packed cobalt nanoparticles starting from low-valent cobalt complexes. By coupling experimental and theoretical studies, we demonstrate that oleylamine promotes the disproportionation of the starting metal complexes and controls the growth of the nanocrystals, in contrast to the role of reducing reagents proposed elsewhere. We also decipher the sensitivity of the synthesis in regard to the nature of the phosphine and of the halogen ligands in the starting cobalt precursors. Understanding of the mechanism allows the development of a less expensive and less toxic synthesis of these nanoparticles by decreasing the amount of oleylamine in alkane solvents. Finally, an extension of this process is presented and allows reaching size- and shape-controlled nanosphere and nanorod nickel nanoparticles.
    Tags: MACO, POLE 1.

  • Y. Wang, P. Pigeon, S. Top, J. García, C. Troufflard, I. Ciofini, M. J. McGlinchey, and G. Jaouen, “Atypical lone pair-π interaction with quinone methides in a series of imido-ferrociphenol anticancer drug candidates”, Angewandte Chemie International Edition, vol. 58, no. ja, p. 8421-8425, 2019.
    Abstract: Ferrociphenols, especially those possessing a heterocycle at the terminus of an aliphatic chain, display strong anticancer activity via a novel redox mechanism that generates active metabolites such as quinone methides (QMs). X-ray crystallography and UV-Vis spectroscopy reveal that the specific lone pair (lp)-π interaction between a carbonyl group of the imide and the quinone motif of the QM plays an important role in the exceptional cytotoxic behaviour of their imido-ferrociphenol precursors. This intramolecular lp-π interaction markedly enhanced the stability of the QMs and lowered the pKa values of the corresponding phenolates. As the first example of such a non-covalent interaction that stabilizes QMs remotely, it not only expands the scope of the lp-π interaction in supramolecular chemistry, but also represents a new mode of stabilization of a QM. This unprecedented application of lp-π interactions in imido-ferrociphenol anticancer drug candidates may also have great potential in drug discovery and organocatalyst design.
    Tags: antitumor agents, bioorganometallics, CHEMBIO, ferrocifen, non-covalent interactions, POLE 3, quinones.
    Note Note

    ss="note"><p>doi: 10.1002/anie.201902456</p>

  • Z. Xia, V. Corcé, F. Zhao, C. Przybylski, A. Espagne, L. Jullien, T. Le Saux, Y. Gimbert, H. Dossmann, V. Mouriès-Mansuy, C. Ollivier, and L. Fensterbank, “Photosensitized oxidative addition to gold(i) enables alkynylative cyclization of o-alkylnylphenols with iodoalkynes”, Nature Chemistry, vol. 11, no. 9, p. 797-805, Sep. 2019.
    Abstract: The well-established oxidative addition–reductive elimination pathway is the most followed one in transition metal-catalysed cross-coupling reactions. While readily occurring with a series of transition metals, gold(i) complexes have shown some reluctance to undergo oxidative addition unless special sets of ligands on gold(i), reagents or reaction conditions are used. Here we show that under visible-light irradiation, an iridium photocatalyst triggers—via triplet sensitization—the oxidative addition of an alkynyl iodide onto a vinylgold(i) intermediate to deliver C(sp)2–C(sp) coupling products after reductive elimination. Mechanistic and modelling studies support that an energy-transfer event takes place, rather than a redox pathway. This particular mode of activation in gold homogenous catalysis was applied in several dual catalytic processes. Alkynylbenzofuran derivatives were obtained from o-alkynylphenols and iodoalkynes in the presence of catalytic gold(i) and iridium(iii) complexes under blue light-emitting diode irradiation.

  • L. Zhang, P. Chen, A. Loiseau, D. Brouri, S. Casale, M. Salmain, S. Boujday, and B. Liedberg, “Spatially Controlled Reduction and Growth of Silver in Hollow Gold Nanoshell Particles”, The Journal of Physical Chemistry C, vol. 123, no. 16, p. 10614-10621, 2019.
    Abstract: Spatially controlled reactions at the nanoscale have attracted increasing interest for fundamental chemistry and for the engineering of novel functional materials. Herein, we demonstrate that pH-triggered reduction of silver ions preferentially occurs at the inner walls of porous and citrate-capped gold nanoshell (AuNS) particles. The reaction initially relies on the presence of sacrificial silver ions inside the AuNS particles as well as in the surrounding preparation solution, and it proceeds upon external addition of silver ions until a solid silver core is formed inside the AuNS particles. Subsequent reduction of silver occurs on the external surface of the solidified AuNS, resulting in a layered and compositionally complex nanoparticle containing both silver and gold. Growth experiments performed in the dark, under white light illumination, as well as near resonance suggest that the reduction reaction is not guided by a plasmonic field enhancement effect. This is in contrast to the recently proposed hot spot mechanism of silver reduction at the rim of nanoholes in a periodic gold array. Our observations point toward a confinement process that proceeds via a continuous supply of silver ions that diffuse from the external solution through the porous shell into the inner volume of the AuNS particles where they become reduced.
    Tags: CHEMBIO, POLE 3.
    Note Note
    <p>doi: 10.1021/acs.jpcc.8b11864</p>

  • L. Zhang, D. Hu, M. Salmain, B. Liedberg, and S. Boujday, “Direct quantification of surface coverage of antibody in IgG-Gold nanoparticles conjugates”, Talanta, vol. 204, p. 875-881, Nov. 2019.
    Abstract: It is of paramount importance to be able to accurately quantify surface coverage of antibodies on gold nanoparticles (AuNP) so as to optimise the sensitivity of AuNP-based immunosensors. Herein, we developed a fluorescence-based method to directly quantify rabbit immunoglobulin G (IgG) used as antibody model bound to AuNP. Rabbit IgG was first labelled with fluorescein-5-isothiocyanate (FITC) prior to conjugation to AuNP via either physisorption or chemisorption. IgG-conjugated AuNP were treated with NaCN to dissolve the AuNP and restore the fluorescence emission that was quenched in the presence of the metallic colloids, followed by quantification of fluorescein by spectrofluorimetry. This direct assay gave about 4 IgG bound to each 15-nm diameter AuNP for both immobilization strategies. This surface coverage value was in good agreement with that determined from the theoretical value calculated from the Localized Surface Plasmon Resonance (LSPR) band shift. For comparison, we also applied two indirect methods based on the quantitation of excess IgG remaining in the supernatant using fluorescence assay or enzyme-linked immunosorbent assay (ELISA). The indirect assays, either fluorescence or ELISA, commonly used to assess the antibody coverage on AuNP, overestimated the IgG surface coverage to a large extent, since up to 3 to 4 times higher coverages were measured. Therefore, the direct fluorescence method reported in this paper appears as a valuable method for quantification of surface coverage of antibody on AuNP.
    Tags: Adsorption, CHEMBIO, Fluorescence, Gold nanoparticles, Immunoglobulin G (IgG), POLE 3, Quantification.

  • L. Zhang, M. Salmain, B. Liedberg, and S. Boujday, “Naked Eye Immunosensing of Food Biotoxins Using Gold Nanoparticle-Antibody Bioconjugates”, ACS Applied Nano Materials, vol. 2, no. 7, p. 4150-4158, 2019.
    Abstract: Colorimetric immunoassays using gold nanoparticles (AuNP) form a special class of assays where AuNP act as a transducer to monitor binding events between an antigen and an antibody. Indeed, AuNP display unique optical properties that can been exploited in various ways to develop biosensors. One of the most striking properties of colloidal AuNP (and more generally of noble metal nanomaterials) is their extremely high extinction coefficient in the visible range of the spectrum owing to the localized surface plasmon resonance (LSPR) phenomenon. This feature makes AuNP detectable down to very low concentrations by absorption spectroscopy or even by the naked eye. Herein we took advantage of the high detectability of AuNP to design a solid-phase, sandwich-type, colorimetric immunosensor aiming at the detection of staphylococcal enterotoxin A (SEA). A test zone comprised of a polyclonal anti-SEA antibody was created at the surface of amino-functionalized glass slides via high affinity binding to covalently immobilized Protein A. The same antibody was conjugated to 13 nm diameter AuNP to afford the nanoimmunoprobe. After the glass slides were successively exposed to SEA and AuNP-antibody bioconjugate, a distinct red spot appeared at the detection zone from as low as 1 ng SEA in buffer. Quantification of SEA in the 10–500 ng/mL range was established using a benchtop UV–visible spectrometer by integration of the LSPR band centered at 530 nm. Eventually, this biosensor was applied to the detection of SEA in milk with a limit of detection of 1.5 ng/mL.
    Tags: CHEMBIO, POLE 3.
    Note Note
    <p>doi: 10.1021/acsanm.9b00598</p>


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