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Peter Licence - One of the best experts on this subject based on the ideXlab platform.

  • Probing the impact of the N3-substituted alkyl chain on the Electronic Environment of the cation and the anion for 1,3-dialkylimidazolium ionic liquids.
    Physical Chemistry Chemical Physics, 2020
    Co-Authors: Peter Licence
    Abstract:

    In this study, X-ray photoelectron spectroscopy is used to probe the impact of the N3-substituted alkyl group on the Electronic Environment of the cation and the anion by comparing two types of imidazolium cations, 1-alkyl-3-butylimidazolium and 1-alkyl-3-methylimidazolium. Due to the more intense inductive effect changing from methyl to butyl, the Electronic Environment of the cationic nitrogen can be significantly affected, which is reflected on a shift of N 1s binding energy. The magnitude of the binding energy shift is found more pronounced in the case of the less basic anion and inversely proportional to the basicity of the anion. The increase of the N3-substituted alkyl chain length can also influence the charge-transfer effect from the anion to the cation. It gives rise to a change in Electronic Environment of the anion. Such an impact is found concentrated on the anion-based component bearing more negative point charges.

  • Probing the Electronic Environment of binary and ternary ionic liquid mixtures by X-ray photoelectron spectroscopy
    Chemical Physics Letters, 2017
    Co-Authors: Peter Licence
    Abstract:

    X-ray photoelectron spectroscopy is used to probe the Electronic Environment of cations and anions for three binary and one ternary chlorostannate ionic liquid mixtures. The impact of the weighting of Cl on the Electronic Environment of the cation-based nitrogen atom is revealed in detail. With the increasing of the concentration of Cl , the N 1s binding energy is decreased. The Electronic Environment of the anion- based component is also compared based upon Sn 3d5/2 and Cl 2p3/2 binding energies. It is found that with the increasing of the weighting of Cl , binding energies of Sn 3d5/2 and Cl 2p3/2 both decrease.

  • Tuning the Electronic Environment of the anion by using binary ionic liquid mixtures
    Chemical Physics Letters, 2017
    Co-Authors: Peter Licence
    Abstract:

    Abstract The Electronic Environment of the anion is tuned by using binary ionic liquid mixtures employing a common anion and two cations with large difference in acidity. X-ray photoelectron spectroscopy is used to monitor the change of the Electronic Environment of the anion by measuring the binding energy of elements present in the anion. It is found that due to the large difference in acidity of the two cations, noticeable shifts can be observed for all anion-based components, no matter how basic the anion is.

  • Directly probing the effect of the solvent on a catalyst Electronic Environment using X-ray photoelectron spectroscopy
    RSC Advances, 2015
    Co-Authors: Kevin R J Lovelock, Peter Licence
    Abstract:

    The Electronic Environment of the metal centre of a catalyst dissolved in ionic liquids has a determining effect on its catalytic efficiency in chemical reactions. However, the Electronic Environment of the ionic liquid-based metal centres can be influenced by not only their chemical state but also the solute–solvent interaction. In this work, we demonstrate that the anion of an ionic liquid can significantly influence the Electronic Environment of a metal centre. The metal centre Electronic Environment can be monitored by measuring the typical electron binding energies by X-ray photoelectron spectroscopy (XPS). The correlation of the Electronic Environment of the metal centre with reaction performance provides a possibility to design and control a chemical reaction. In this work, we also illustrate a strategy for tuning the Electronic Environment of metal centres, by the selection of particular ionic liquid anions, to design a catalytic system and consequently to finally control the reaction performance of a model Suzuki cross coupling reaction.

  • tuning the Electronic Environment of cations and anions using ionic liquid mixtures
    Chemical Science, 2014
    Co-Authors: Ignacio J Villargarcia, Kevin R J Lovelock, Peter Licence
    Abstract:

    Electrostatic interactions are ubiquitous in ionic liquids and therefore, the Electronic Environment (i.e. the distribution of electron density) of their constituent ions has a determining influence on their properties and applications. Moreover, the distribution of electron density on atoms is at the core of ionic liquid molecular dynamics simulations. In this work, we demonstrate that changing the composition of ionic liquid mixtures can tune the Electronic Environment of their constituent ions, both anions and cations. The Electronic Environment of these ions can be monitored by measuring the characteristic electron binding energies of their constituent atoms by X-ray photoelectron spectroscopy (XPS). The possibility to fine tune, in a controlled way, the Electronic Environment of specific ions provides an invaluable tool to understand ionic liquid properties and allows the design of ionic liquid mixtures towards specific applications. Here, we demonstrate the power of this tool by tuning the Electronic Environment of a catalytic centre, and consequently its catalytic activity, by the use of ionic liquid mixtures.

Kevin R J Lovelock - One of the best experts on this subject based on the ideXlab platform.

  • Directly probing the effect of the solvent on a catalyst Electronic Environment using X-ray photoelectron spectroscopy
    RSC Advances, 2015
    Co-Authors: Kevin R J Lovelock, Peter Licence
    Abstract:

    The Electronic Environment of the metal centre of a catalyst dissolved in ionic liquids has a determining effect on its catalytic efficiency in chemical reactions. However, the Electronic Environment of the ionic liquid-based metal centres can be influenced by not only their chemical state but also the solute–solvent interaction. In this work, we demonstrate that the anion of an ionic liquid can significantly influence the Electronic Environment of a metal centre. The metal centre Electronic Environment can be monitored by measuring the typical electron binding energies by X-ray photoelectron spectroscopy (XPS). The correlation of the Electronic Environment of the metal centre with reaction performance provides a possibility to design and control a chemical reaction. In this work, we also illustrate a strategy for tuning the Electronic Environment of metal centres, by the selection of particular ionic liquid anions, to design a catalytic system and consequently to finally control the reaction performance of a model Suzuki cross coupling reaction.

  • tuning the Electronic Environment of cations and anions using ionic liquid mixtures
    Chemical Science, 2014
    Co-Authors: Ignacio J Villargarcia, Kevin R J Lovelock, Peter Licence
    Abstract:

    Electrostatic interactions are ubiquitous in ionic liquids and therefore, the Electronic Environment (i.e. the distribution of electron density) of their constituent ions has a determining influence on their properties and applications. Moreover, the distribution of electron density on atoms is at the core of ionic liquid molecular dynamics simulations. In this work, we demonstrate that changing the composition of ionic liquid mixtures can tune the Electronic Environment of their constituent ions, both anions and cations. The Electronic Environment of these ions can be monitored by measuring the characteristic electron binding energies of their constituent atoms by X-ray photoelectron spectroscopy (XPS). The possibility to fine tune, in a controlled way, the Electronic Environment of specific ions provides an invaluable tool to understand ionic liquid properties and allows the design of ionic liquid mixtures towards specific applications. Here, we demonstrate the power of this tool by tuning the Electronic Environment of a catalytic centre, and consequently its catalytic activity, by the use of ionic liquid mixtures.

  • Amino acid-based ionic liquids: using XPS to probe the Electronic Environment via binding energies
    Physical Chemistry Chemical Physics, 2011
    Co-Authors: Bitu Birru Hurisso, Kevin R J Lovelock, Peter Licence
    Abstract:

    Here we report the synthesis and characterisation by X-ray photoelectron spectroscopy (XPS) of eight high purity amino acid-based ionic liquids (AAILs), each containing the 1-octyl-3-methylimidazolium, [C8C1Im]+, as a standard reference cation. All expected elements were observed and the Electronic Environments of these elements identified. A fitting model for the carbon 1s region of the AAILs is reported; the C aliphatic component of the cation was used as an internal reference to obtain a series of accurate and reproducible binding energies. Comparisons are made between XP spectra of the eight AAILs and selected non-functionalised ionic liquids. 1-octyl-3-methylimidazolium acetate was also studied as a model of the carboxyl containing amino acid anion. The influence of anionic substituent groups on the measured binding energies of all elements is presented, and communication between anion and cation is investigated. This data is interpreted in terms of hard and soft anions and compared to the Kamlet–Taft hydrogen bond acceptor ability, β, for the ionic liquids. A linear correlation is presented which suggests that the functional side chain, or R group, of the amino acid has little impact upon the Electronic Environment of the charge-bearing moieties within the anions and cations studied.

Lluis Anglada - One of the best experts on this subject based on the ideXlab platform.

  • faculty information behaviour in the Electronic Environment
    New Library World, 2016
    Co-Authors: Angel Borrego, Lluis Anglada
    Abstract:

    Purpose – This study aims to investigate how the transition from print to Electronic scholarly communication has affected faculty’s information behaviour and their perception of academic libraries. Design/methodology/approach – An online survey was distributed among academics affiliated to the member universities of the Consortium of University Services of Catalonia. A total of 2,230 replies were received. Findings – Journal articles are the most relevant information resource used for research and teaching purposes. Databases are the preferred starting point for bibliographic searches, although a significant proportion of scholars rely on Internet search engines. The main source for gaining access to documents is libraries, followed by free materials available online. Scholarly journals are the preferred channel for disseminating research outputs, with the open access being a factor of marginal interest when deciding where to publish. Originality/value – The results of this study should be useful to guide...

S. Parker - One of the best experts on this subject based on the ideXlab platform.

Wen Yang - One of the best experts on this subject based on the ideXlab platform.

  • Pure dephasing of single Mn spin in semiconductor quantum dots
    Physical Review B, 2017
    Co-Authors: Dingyang Liu, Wenxi Lai, Wen Yang
    Abstract:

    © 2017 American Physical Society. We present comprehensive analytical and numerical studies on the pure dephasing of a single Mn spin in a semiconductor quantum dot due to (i) its sp-d exchange interaction with an Electronic Environment, and (ii) its hyperfine interaction with the nuclear spin Environment. For (i), by modeling the Electronic Environment by an open two-level system, we provide exact analytical expressions and present deta iled analysis for the Mn spin pure dephasing in both the Markovian and non-Markovian regimes. This provides a clear physical picture and a general theoretical framework based on which we estimate the Mn spin pure dephasing due to various fluctuations (such as thermal excitation, optical pumping, tunneling, or electron/hole spin relaxation) of the Electronic Environment and reveals a series of interesting behaviors, such as thermal, optical, and electrical control of the crossover between the Markov and non-Markov regimes. In particular, we find rapid Mn spin pure dephasing on a nanosecond time scale by the thermal fluctuation and optical pumping, but these mechanisms can be strongly suppressed by shifting the electron envelope function relative to the Mn atom with an external electric field through the quantum-confined Stark effect. The thermal fluctuation mechanism is also exponentially suppressed at low temperature. For (ii), we find that the Mn spin dephasing time is limited by the thermal fluctuation of the nuclear spins to a few microseconds even at low temperature and its value varies from sample to sample, depending on the distribution of spinful isotopes on the nearest-neighbor sites surrounding the substitutional Mn atom. Our findings may be useful to understand and suppress the Mn spin pure dephasing for its applications in quantum information processing.