Nickel-containing di-charged imidazolium ligand with high crystalline organization. Interception and characterization of a transient carbene/cation species

International audienceNew nickel-containing di-charged imidazolium-based molten salt (2) was prepared by treatment of nickel chloride with bis-(2-(3-methylimidazolium-1-yl)ethyl)ether dichloride (1) in good yield. This compound has been fully characterized by elemental analysis, polarized optical microscopy (POM), differential scanning calorimetry (DSC), powder and single-crystal X-ray diffraction, and electrospray mass spectrometry. X-ray diffraction studies of 2 revealed a quite interesting 3D organization whereas cations and anions each arrange in individual chains, which are themselves connected in an extended, columnar-type network. Furthermore the presence of [NiCl4]2− unit in compound 2 induces a 3D crystalline arrangement much higher than that observed for compound 1. The ESI(+)-MS studies show the same set of fragments detected for both compound 1 and 2 displaying similar losses including the presence of a di-charged molecule. The fragmentation of nickel-containing compound 2 gave a very high intense cation-carbene ion of m/z 235, suggesting an additional stabilization by the presence of [NiCl4]2− unit in the structure of 2 related to the low intensity signal found for 1 in the same m/z

Les structures attribuables au Néolithique moyen de type La Roberte (fin du Ve millénaire-début du IVe millénaire avant notre ère)

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Les structures attribuables au Néolithique moyen de type La Roberte (fin du Ve millénaire-début du IVe millénaire avant notre ère)

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Les structures attribuables au Néolithique moyen de type La Roberte (fin du Ve millénaire-début du IVe millénaire avant notre ère)

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Les apports du site pour la connaissance du Néolithique moyen

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Les apports du site pour la connaissance du Néolithique moyen

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Les structures attribuables au Néolithique moyen de type Chassey (dernier tiers du Ve millénaire avant notre ère)

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Les structures attribuables au Néolithique moyen de type Chassey (dernier tiers du Ve millénaire avant notre ère)

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Two-particle transverse momentum correlations in pp and p-Pb collisions at LHC energies

Two-particle transverse momentum differential correlators, recently measured in Pb-Pb collisions at LHC energies, provide an additional tool to gain insights into particle production mechanisms and infer transport properties, such as the ratio of shear viscosity to entropy density, of the medium created in Pb--Pb collisions. The longitudinal long-range correlations and the large azimuthal anisotropy measured at low transverse momenta in small collision systems, namely pp and p-Pb, at LHC energies resemble manifestations of collective behaviour. This suggests that locally equilibrated matter may be produced in these small collision systems, similar to what is observed in Pb-Pb collisions. In this work, the same two-particle transverse momentum differential correlators are exploited in pp and p-Pb collisions at $\sqrt{s} = 7$ TeV and $\sqrt{s_{\rm NN}} = 5.02$ TeV, respectively, to seek evidence for viscous effects. Specifically, the strength and shape of the correlators are studied as a function of the produced particle multiplicity to identify evidence for longitudinal broadening that might reveal the presence of viscous effects in these smaller systems. The measured correlators and their evolution from pp and p-Pb to Pb-Pb collisions are additionally compared to predictions from Monte Carlo event generators, and the potential presence of viscous effects is discussed.Two-particle transverse momentum differential correlators, recently measured in Pb--Pb collisions at energies available at the CERN Large Hadron Collider (LHC), provide an additional tool to gain insights into particle production mechanisms and infer transport properties, such as the ratio of shear viscosity to entropy density, of the medium created in Pb-Pb collisions. The longitudinal long-range correlations and the large azimuthal anisotropy measured at low transverse momenta in small collision systems, namely pp and p-Pb, at LHC energies resemble manifestations of collective behaviour. This suggests that locally equilibrated matter may be produced in these small collision systems, similar to what is observed in Pb-Pb collisions. In this work, the same two-particle transverse momentum differential correlators are exploited in pp and p-Pb collisions at $\sqrt{s} = 7$ TeV and $\sqrt{s_{\rm NN}} = 5.02$ TeV, respectively, to seek evidence for viscous effects. Specifically, the strength and shape of the correlators are studied as a function of the produced particle multiplicity to identify evidence for longitudinal broadening that might reveal the presence of viscous effects in these smaller systems. The measured correlators and their evolution from pp and p--Pb to Pb--Pb collisions are additionally compared to predictions from Monte Carlo event generators, and the potential presence of viscous effects is discussed.Two-particle transverse momentum differential correlators, recently measured in Pb-Pb collisions at energies available at the CERN Large Hadron Collider (LHC), provide an additional tool to gain insights into particle production mechanisms and infer transport properties, such as the ratio of shear viscosity to entropy density, of the medium created in Pb-Pb collisions. The longitudinal long-range correlations and the large azimuthal anisotropy measured at low transverse momenta in small collision systems, namely pp and p-Pb, at LHC energies resemble manifestations of collective behavior. This suggests that locally equilibrated matter may be produced in these small collision systems, similar to what is observed in Pb-Pb collisions. In this work, the same two-particle transverse momentum differential correlators are exploited in pp and p-Pb collisions at s=7TeV and sNN=5.02TeV, respectively, to seek evidence for viscous effects. Specifically, the strength and shape of the correlators are studied as a function of the produced particle multiplicity to identify evidence for longitudinal broadening that might reveal the presence of viscous effects in these smaller systems. The measured correlators and their evolution from pp and p-Pb to Pb-Pb collisions are additionally compared to predictions from Monte Carlo event generators, and the potential presence of viscous effects is discussed