353 research outputs found

    Optical and XPS evidence for the electrochemical generation of an N-heterocyclic carbene and its CS2 adduct from the ionic liquid [bmim][PF6]

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    Room temperature ionic liquids continue to be at the forefront of chemistry, covering a broad spectrum of research areas from electrochemistry and energy to catalysis and green chemistry. Therefore, it is of great value to fully understand the chemical and electrochemical reactivity and stability of ionic liquids utilized in these applications. In this context, we have investigated the electrochemical generation of an N-heterocyclic carbene and its CS2 adduct from the ionic liquid [bmim][PF6], and X-ray photoelectron spectroscopy (XPS) proved to be a highly effective spectroscopic tool to study such systems. Initially, the dithiocarboxylate adduct was chemically synthesized as a reference compound starting from both [bmim][PF6] and [bmim][OAc], and characterized by HRMS, and 1H- and 13C-NMR, FTIR, visible and X-ray photoelectron spectroscopy. While a simple mixture of [bmim][PF6] and CS2 revealed no evidence of adduct formation, the application of an electrochemical stimulus led to the formation of the dithiocarboxylate adduct as evidenced optically and through the newly formed S2p peak in the XP spectrum. Further evidence for the electrochemical reduction of [bmim][PF6] to the corresponding N-heterocyclic carbene came from the XPS analysis via the appearance of a new N1s peak in the XP spectrum. © 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique

    XPS-evidence for in-situ electrochemically-generated carbene formation

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    Stable N-heterocyclic carbenes (NHC) are a class of compounds that has attracted a huge amount of interest in the last decade. One way to prepare NHCs is through chemical or electrochemical reduction of 1,3-disubstituted imidazolium cations. We are presenting an in-situ electrochemical X-ray Photoelectron Spectroscopy (XPS) study where electrochemically reduced imidazolium cations lead to production of stable NHC. The electroactive imidazolium species is not only the reactant, but also part of the ionic liquid which serves as the electrolyte, the medium and the electroactive material. This allows us to directly probe the difference between the parent imidazolium ion and the NHC through the use of XPS. The interpretation of the results is supported by both observation of reversible redox peaks in the voltammogram and the density functional theory calculations. © 2017 Elsevier Lt

    Image-guided ToF depth upsampling: a survey

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    Recently, there has been remarkable growth of interest in the development and applications of time-of-flight (ToF) depth cameras. Despite the permanent improvement of their characteristics, the practical applicability of ToF cameras is still limited by low resolution and quality of depth measurements. This has motivated many researchers to combine ToF cameras with other sensors in order to enhance and upsample depth images. In this paper, we review the approaches that couple ToF depth images with high-resolution optical images. Other classes of upsampling methods are also briefly discussed. Finally, we provide an overview of performance evaluation tests presented in the related studies

    Comparison of inclusive and photon-tagged jet suppression in 5.02 TeV Pb+Pb collisions with ATLAS

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    Studies of new Higgs boson interactions through nonresonant HH production in the b¯bγγ fnal state in pp collisions at √s = 13 TeV with the ATLAS detector