106 research outputs found
Rigid probe solutes in a smectic-A liquid crystal: An unconventional route to the latter's positional order parameters
Biphenylene and pyrene were dissolved in the nematic and smectic-A phases of the liquid crystal 4,4â-di-n-heptyl-azoxybenzene and the orientational order parameters of both solutes and solvent measured via proton and deuteron nuclear-magnetic-resonance spectroscopy. This new data set was then merged with the one previously obtained, formed by 4,4â-di-chloro-benzene and naphthalene as solutes in the same solvent, and the resulting overall data set analyzed with a statistical thermodynamic density-functional theory to provide positional-orientational distribution functions of the various solutes along with the smectic solventâs positional order parametersM.E.D.P. is grateful to the European Commission, the European Social Fund, and the Regione Calabria for cofunding her Ph.D. scholarship. M.E.D.P., G.C., and G.D.L. thank the University of Calabria and MIUR PRIN 2009 for financial support. G.C. acknowledges the financial support of the Spanish Ministry of Research via a RaĂłon y Cajal research fellowshi
Correction: Conformational features of 4-(N)-squalenoyl-gemcitabine in solution: a combined NMR and molecular dynamics investigation
Correction for 'Conformational features of 4-(N)-squalenoyl-gemcitabine in solution: a combined NMR and molecular dynamics investigation' by Ceruti Maurizio et al., New J. Chem., 2015, 39, 3484â3496
Insights into the Effect of Lithium Doping on the Deep Eutectic Solvent Choline Chloride: Urea
Choline-based deep eutectic solvents (DESs) are potential candidates to replace flammable
organic solvent electrolytes in lithium-ion batteries (LIBs). The effect of the addition of a lithium salt
on the structure and dynamics of the material needs to be clarified before it enters the battery. Here,
the archetypical DES choline chloride:urea at 1:2 mole fraction has been added with lithium chloride
at two different concentrations and the effect of the additional cation has been evaluated with
respect to the non-doped system via multinuclear NMR techniques. 1H and 7Li spin-lattice
relaxation times and diffusion coefficients have been measured between 298 K and 373 K and
revealed a decrease in both rotational and translational mobility of the species after LiCl doping at
a given temperature. Temperature dependent 35Cl linewidths reflect the viscosity increase upon LiCl
addition, yet keep track of the lithium complexation. Quantitative indicators such as correlation
times and activation energies give indirect insights into the intermolecular interactions of the
mixtures, while lithium single-jump distance and transference number shed light into the lithium
transport, being then of help in the design of future DES electrolytes
Reinforcing the Electrode/Electrolyte Interphases of Lithium Metal Batteries Employing Locally Concentrated Ionic Liquid Electrolytes
Lithium metal batteries (LMBs) with nickel-rich cathodes are promising candidates for next-generation high-energy-density batteries, but the lack of sufficiently protective electrode/electrolyte interphases (EEIs) limits their cyclability. Herein, trifluoromethoxybenzene is proposed as a cosolvent for locally concentrated ionic liquid electrolytes (LCILEs) to reinforce the EEIs. With a comparative study of a neat ionic liquid electrolyte (ILE) and three LCILEs employing fluorobenzene, trifluoromethylbenzene, or trifluoromethoxybenzene as cosolvents, it is revealed that the fluorinated groups tethered to the benzene ring of the cosolvents not only affect the electrolytesâ ionic conductivity and fluidity, but also the EEIsâ composition via adjusting the contribution of the 1-ethyl-3-methylimidazolium cation (Emim) and bis(fluorosulfonyl)imide anion. Trifluoromethoxybenzene, as the optimal cosolvent, leads to a stable cycling of LMBs employing 5 mAh cm lithium metal anodes (LMAs), 21 mg cm LiNiCoAl (NCA) cathodes, and 4.2 ÂľL mAh electrolytes for 150 cycles with a remarkable capacity retention of 71%, thanks to a solid electrolyte interphase rich in inorganic species on LMAs and, particularly, a uniform cathode/electrolyte interphase rich in Emim-derived species on NCA cathodes. By contrast, the capacity retention under the same condition is only 16%, 46%, and 18% for the neat ILE and the LCILEs based on fluorobenzene and benzotrifluoride, respectively
Locally Concentrated Ionic Liquid Electrolyte with Partially Solvating Diluent for Lithium/Sulfurized Polyacrylonitrile Batteries
The development of Li/sulfurized polyacrylonitrile (SPAN) batteries requires electrolytes that can form stable electrolyte/electrode interphases simultaneously on lithium-metal anodes (LMAs) and SPAN cathodes. Herein, a low-flammability locally concentrated ionic liquid electrolyte (LCILE) employing monofluorobenzene (mFBn) as the diluent is proposed for Li/SPAN cells. Unlike non-solvating diluents in other LCILEs, mFBn partially solvates Li, decreasing the coordination between Li and bis(fluorosulfonyl)imide (FSI). In turn, this triggers a more substantial decomposition of FSI and consequently results in the formation of a solid electrolyte interphase (SEI) rich in inorganic compounds, which enables a remarkable Coulombic efficiency (99.72%) of LMAs. Meanwhile, a protective cathode electrolyte interphase (CEI), derived mainly from FSI and organic cations, is generated on the SPAN cathodes, preventing the dissolution of polysulfides. Benefiting from the robust interphases simultaneously formed on both the electrodes, a highly stable cycling of Li/SPAN cells for 250 cycles with a capacity retention of 71% is achieved employing the LCILE and only 80% lithium-metal excess
DifluorobenzeneâBased Locally Concentrated Ionic Liquid Electrolyte Enabling Stable Cycling of Lithium Metal Batteries with NickelâRich Cathode
Lithium metal batteries (LMBs) with nickel-rich cathodes are promising candidates for next-generation, high-energy batteries. However, the highly reactive electrodes usually exhibit poor interfacial compatibility with conventional electrolytes, leading to limited cyclability. Herein, a locally concentrated ionic liquid electrolyte (LCILE) consisting of lithium bis(fluorosulfonyl)imide (LiFSI), 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EmimFSI), and 1,2-difluorobenzene (dFBn) is designed to overcome this challenge. As a cosolvent, dFBn not only promotes the Li transport with respect to the electrolyte based on the ionic liquid only, but also has beneficial effects on the electrode/electrolyte interphases (EEIs) on lithium metal anodes (LMAs) and LiNiMnCoO (NMC811) cathodes. As a result, the developed LCILE enables dendrite-free cycling of LMAs with a coulombic efficiency (CE) up to 99.57% at 0.5 mA cm and highly stable cycling of Li/NMC811 cells (4.4 V) at C/3 charge and 1 C discharge (1 C = 2 mA cmâ2) for 500 cycles with a capacity retention of 93%. In contrast, the dFBn-free electrolyte achieves lithium stripping/plating CE, and the Li/NMC811 cellsâ capacity retention of only 98.22% and 16%, respectively under the same conditions. The insight into the coordination structure, promoted Li transport, and EEI characteristics gives fundamental information essential for further developing (IL-based) electrolytes for long-life, high-energy LMBs
Effect of organic cations in locally concentrated ionic liquid electrolytes on the electrochemical performance of lithium metal batteries
Urinary Metabolic Profile of Patients with Transfusion-Dependent β-Thalassemia Major Undergoing Deferasirox Therapy
Introduction: Renal dysfunction is a frequent complication in patients suffering from β-thalassemia major (β-TM). The aim of this study was to analyze the renal function and urine metabolomic profile of β-TM patients undergoing transfusions and deferasirox (DFX) therapy, in order to better characterize and shed light on the pathogenesis of renal disease in this setting. Methods and Subjects: 40 patients affected by β-TM treated with DFX and 35 age- and gender-matched healthy controls were enrolled in the study. Renal function was assessed. Glomerular filtration rate (GFR) was estimated with CKD-EPI and Schwartz formula for adults and children, respectively. Renal tubular function and maximal urine concentration ability were tested. Urine specimens were analyzed by nuclear magnetic resonance spectroscopy to identify the urinary metabolite profiles. Results: The study of renal function in β-TM patients revealed normal estimated (e)GFR mean values and the albumin-to-creatinine ratio was <30 mg/g. The analysis of tubular function showed normal basal plasma electrolyte levels; 60% of patients presented hypercalciuria and many subjects showed defective urine concentration. Several amino acids, N-methyl compounds, and organic acids were overexcreted in the urine of thalassemic patients compared with controls. Discussion: The major finding of this work is that β-TM patients and controls exhibit different concentrations of some metabolites in the urine. Early recognition of urinary abnormalities may be useful to detect and prevent kidney damage
The Complex Story Behind a Deep Eutectic Solvent Formation as Revealed by LâMenthol Mixtures with Butylated Hydroxytoluene Derivatives.
An in-depth study of the hydrophobic eutectic mixtures formed by
L-menthol (MEN) with the butylated hydroxytoluene (BHT), 2-tert-butyl-pcresol (TBC), and p-cresol (PC) compounds has been carried out, where TBC
and PC are analogous to the BHT species but with a different degree of steric
hindrance around the hydroxyl group. Thermal characterization evidenced that
the BHT/MEN system can be classified as an ideal eutectic, while the TBC/MEN
and PC/MEN mixtures behave as type V deep eutectic solvents (DESs) for a
wide range of compositions around the eutectic point. As shown by an array of
experimental and theoretical methods, in the BHT/MEN mixtures the
establishment of hydrogen-bond (H-bond) interactions between the components
is dramatically hampered because of the steric hindrance in the BHT molecule, so
that the achievement of a liquid phase at room temperature for the eutectic
composition is driven by apolarâapolar attractions among the alkyl functional
groups of the constituents. Differently, the TBC-MEN donorâreceptor H-bond is
the main driving force for the formation of a type V DES and derives from a concurrence of electronic and steric factors
characterizing the TBC molecule. Finally, the absence of steric hindrance around the hydroxyl group allows the self-association
among PC molecules through H-bonded networks already in the pristine compound, but the replacement with the more favorable
PC-MEN H-bond provides a type V DES upon mixing of these components. Our combined approach, together with the peculiarity
of the inspected systems, delivered an archetypal study able to shed light onto the various contributions ruling the structureâ
properties relationship in DESs and possibly deepening the currently accepted view of these inherently complex media
- âŚ