An innovative deep eutectic solvent: chalcogen bonding as the primary driving force.

Chalcogen bonding (ChB) interactions have drawn intensive attention in the last few decades as interesting alternatives to hydrogen bonding. The applications of ChB were mostly centered on the solid state and have rarely been explored in solution. In this work, a novel strategy for forming ChB-based deep eutectic solvents (DESs) was exploited. We set forth the formation, physicochemical properties, and interaction sites in detail. This work not only provides a new idea to design DES systems but also to exploit the potential application of ChB complexes.

Yet another perspective on hole interactions, part II: lp-hole vs. lp-hole interactions.

Most of the experimental and theoretical work in hole interactions (HIs) is mainly focused on exploiting the nature and characteristics of σ and π-holes. In this perspective, we focus our attention on understanding the origin and properties of lone-pair holes. These holes are present on an atom opposite to its lone-pair region. Utilizing some new and old examples, such as X3N/P⋯F- (X = F/Cl/Br/I), F-Cl/Br/I⋯H3P⋯NCH and H3B-NBr3 along with other molecular systems, we explored to what extent these lp-holes participate in lp-hole interactions, if they participate at all.

Chitosan modified with bio-extract as an antibacterial coating with UV filtering feature.

Benzophenone-3 grafted chitosan (CS-BP-3) was successfully synthesized and applied as an antibacterial coating for the first time. The grafting mechanism is based on the reaction between ketone and primary amine to form imine derivatives and the chemical structure of grafted chitosan was studied by Fourier transform infrared (FT-IR) spectroscopy. Water solubility of BP-3 is enhanced after covalently grafted on chitosan and consequently renders the chitosan coating with UV blocking property. Results of thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) further confirmed the thermal stability of BP-3 modified chitosan is enhanced. The CS-BP-3 coating was applied on a variety of substrates of glass, plastics, wood, and metal. The surface features of the coatings such as morphology, water contact angle (WCA), and surface roughness were investigated. The optical and thermal stabilities of the coatings under UV irradiation were studied for 16 h. Antibacterial activity of CS-BP-3 was evaluated against both Gram-negative and Gram-positive bacteria. And the results of bacterial inhibition by CS-BP-3 coating indicate its potential for future application in food packaging.

Effect of Surface Charge on the Fabrication of Hierarchical Mn-Based Prussian Blue Analogue for Capacitive Desalination.

Multiple and hierarchical manganese (Mn)-based Prussian blue analogues obtained on different substrates are successfully prepared using a universal, facile, and simple strategy. Different functional groups and surface charge distributions on carbon cloth have significant effects on the morphologies and nanostructures of Mn-based Prussian blue analogues, thereby indirectly affecting their physicochemical properties. Combined with the advantages of the modified carbon cloth and the nanostructured Mn-based Prussian blue analogues, the composite with negative surface charge formed by the electronegativity differences shows good electrochemical properties, leading to improvement in charge efficiency during capacitive desalination. An asymmetric device fabricated with Mn-based Prussian blue analogue-modified F-doped carbon cloth as the cathode and acid-treated carbon cloth as the anode presents the highest salt adsorption capacity of 10.92 mg g-1 with a charge efficiency of 82.28% and the lowest energy consumption of 0.45 kW h m-3 at 1 V due to the main influencing factor from the negative surface charge leading to co-ion expulsion boosting the capacitive deionization performance. We provide insights for further exploration of the relationship between second-phase materials and carbon cloth, while offering some guidance for the design and preparation of electrodes for desalination and beyond.

An emerging deep eutectic solvent based on halogen-bonds.

A new deep eutectic solvent (DES) driven by halogen bonding (XB) was exploited. A family of eutectic mixtures in the liquid state was obtained by the combination of quaternary ammonium salts and dihalogens. The formation mechanism was discussed based on experiments and DFT calculations. It not only broadens the potential DES systems but unlocks the possibility of XB complexes as solvents.

Correction: Eutectics: formation, properties, and applications.

Correction for 'Eutectics: formation, properties, and applications' by Dongkun Yu et al., Chem. Soc. Rev., 2021, DOI: .

Eutectics: formation, properties, and applications.

Various eutectic systems have been proposed and studied over the past few decades. Most of the studies have focused on three typical types of eutectics: eutectic metals, eutectic salts, and deep eutectic solvents. On the one hand, they are all eutectic systems, and their eutectic principle is the same. On the other hand, they are representative of metals, inorganic salts, and organic substances, respectively. They have applications in almost all fields related to chemistry. Their different but overlapping applications stem from their very different properties. In addition, the proposal of new eutectic systems has greatly boosted the development of cross-field research involving chemistry, materials, engineering, and energy. The goal of this review is to provide a comprehensive overview of these typical eutectics and describe task-specific strategies to address growing demands.

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas.

The reductive carbonylation of aryl iodides to aryl aldehydes possesses broad application prospects. We present an efficient and facile Rh-based catalytic system composed of the commercially available Rh salt RhCl3·3H2O, PPh3 as phosphine ligand, and Et3N as the base, for the synthesis of arylaldehydes via the reductive carbonylation of aryl iodides with CO and H2 under relatively mild conditions with a broad substrate range affording the products in good to excellent yields. Systematic investigations were carried out to study the experimental parameters. We explored the optimal ratio of Rh salt and PPh3 ligand, substrate scope, carbonyl source and hydrogen source, and the reaction mechanism. Particularly, a scaled-up experiment indicated that the catalytic method could find valuable applications in industrial productions. The low gas pressure, cheap ligand and low metal dosage could significantly improve the practicability in both chemical researches and industrial applications.

Preparation of cyclic imides from alkene-tethered amides: application of homogeneous Cu(ii) catalytic systems.

A Cu-based homogeneous catalytic system was proposed for the preparation of imides from alkene-tethered amides. Here, O2 acted as a terminal oxidant and a cheap and easily available oxygen source. The cleavage of C[double bond, length as m-dash]C bonds and the formation of C-N bonds were catalyzed by Cu(ii) salts with proper nitrogen-containing ligands under 100 °C. The synthesis approach has potential applications in pharmaceutical syntheses. Moreover, scaled-up experiments confirmed the practical applicability.

"Inverted" Deep Eutectic Solvents Based on Host-Guest Interactions.

Herein, the concept of "inverted" (the mode "molecules mainly interact with cations") deep eutectic solvents (DESs) is proposed. A strategy to form inverted DESs by host-guest interactions was developed, and thus numerous DESs could be designed and formed by a combination of host and guest molecules. These liquids are expected to be used as nonaqueous electrolytes in potassium-ion batteries or other fields for further exploration.

Fabricating Amorphous g-C3N4/ZrO2 Photocatalysts by One-Step Pyrolysis for Solar-Driven Ambient Ammonia Synthesis.

Solar-driven nitrogen fixation remains a significant challenge. Graphitic carbon nitride (g-C3N4) is considered as a promising visible light photocatalyst. However, the photocatalytic performance of g-C3N4 is unsatisfactory because of the random transfer of charge carriers in the plane and the low activation efficiency of the reactants. Herein, amorphous ZrO2 was used as a robust cocatalyst of g-C3N4 to increase the NH3 production activity. The g-C3N4/ZrO2 lamellar composites were constructed by a simple one-step pyrolysis of the deep eutectic solvent ZrOCl2·8H2O/urea. The optimum NH4+ yield could reach as high as 1446 µmol·L-1·h-1 at 30 wt % ZrO2 in the g-C3N4/ZrO2 composites, with an apparent quantum efficiency over 2.14% at 400 nm. It is 7.9 times that of pristine g-C3N4 and 27.5 times that of ZrO2. The introduction of amorphous ZrO2 restrained the hydrogen generation, and the amorphous ZrO2 and g-C3N4 together contribute to the rapid photoproduced electron transfer of less electron-hole pair recombination.

Eutectic Molecular Liquids Based on Hydrogen Bonding and π-π Interaction for Exfoliating Two-dimensional Materials and Recycling Polymers.

Eutectic molecular liquids (EMLs) based on hydrogen-bonding interaction and π-π stacking were prepared. We found that the thermodynamic properties like initial decomposition temperature and glass transition temperature of EMLs are mainly dominated by the hydrogen bond donor, which is beneficial for designing and preparing new EMLs. These new liquid systems could be applied in the field of environmental and material science.

Strategy To Form Eutectic Molecular Liquids Based on Noncovalent Interactions.

The concept of eutectic molecular liquids (EMLs) was defined, and a strategy to form EMLs based on noncovalent interactions was proposed. We verified the formation and investigated the properties, interaction sites, and interaction energies of the obtained 16 EMLs. Moreover, two new forms of noncovalent interactions, κ-hole and µ-hole bonding interactions, were proposed, which broaden the understanding of intermolecular interactions. Numerous EMLs can be strategically designed and prepared by simply mixing two parent molecule components based on noncovalent interactions, including hydrogen bonding interactions; π-π stacking; and σ-hole (halogen, chalcogen, pnicogen, and tetrel bonds), π-hole, κ-hole, and µ-hole bonding interactions. The properties of EMLs can be finely tailored by selecting or even designing appropriate parent compounds for task-specific applications. Our work presents a substantial step toward the innovative development of liquid systems.

The dynamic evaporation process of the deep eutectic solvent LiTf2N:N-methylacetamide at ambient temperature.

Lithium-based deep eutectic solvents (DESs) are potential and promising electrolytes for energy-storing devices such as the lithium-ion battery and supercapacitor due to their greenness, low cost, favorable stability, and ease of synthesis. LiTf2N (lithium bis(trifluoromethylsulfonyl)imide):NMA (N-methylacetamide) is a liquid due to the strong intermolecular H-bonding interaction between the H-bonding acceptor (HBA, LiTf2N) and H-bonding donor (HBD, NMA). The properties (melting point, conductivity, viscosity, etc.) of LiTf2N:NMA change with the evaporation of NMA from LiTf2N:NMA, which would further influence the performance of the energy-storing devices. The evaporation of DES should be determined by the intermolecular interactions. Here, for the first time, the dynamic process of evaporation and intermolecular interactions of the DES LiTf2N:NMA at room temperature were investigated and we find that the evaporation mechanism of the DES LiTf2N:NMA can be divided into three stages. In the first stage (before 110 min), the H-bonding interaction between O in LiTf2N and NH in NMA is disrupted before destruction of the coordinating interaction related to amide II C[double bond, length as m-dash]O and Li cation. In the second stage (from 110 min to 270 min), the change of coordinating interaction related to amide II C[double bond, length as m-dash]O and Li cation is also higher than that of the H-bonded interaction. In the third stage (after 270 min), evaporation of NMA from LiTf2N:NMA has very little influence on the environment of LiTf2N:NMA. This work provides a guide for designing DESs as electrolytes for energy-storing devices such as the lithium-ion battery and supercapacitor.

Water absorption by deep eutectic solvents.

Deep eutectic solvents (DESs) are one type of green solvents. Most of the DESs could absorb water from air. However, even a trace amount of water can affect the chemical structure and physical properties of DESs. To date, no study has been reported on the hygroscopicity of DESs. Consequently, in this study, a comprehensive investigation was performed on the capacity, kinetics, mechanism, and furthermore the dynamic process (by PCMW2D-COS IR spectra) of atmospheric water absorption from air by DESs. The results show that most DESs are highly hygroscopic. Surface absorption enhances the overall water absorption capacity by DESs in spite of decreasing the initial water absorption rate. In the beginning, the water absorption increases with an increase in the number of hydrophilic groups in DESs due to the retained DES nanostructure during this period. Therefore, DESs with more hydrophilic groups (ChCl:glucose than ChCl:xylitol) possess a higher water absorption initial rate. However, when the water absorption capacity is high, the hindrance from the H-bond strength from inner DESs needs to be overcome for the absorption of more water. In this case, DESs with stronger H-bonds (ChCl:glucose than ChCl:xylitol) have a lower steady-state water absorption capacity and an easier equilibrium.

Deep eutectic-solvothermal synthesis of nanostructured Fe3S4 for electrochemical N2 fixation under ambient conditions.

We report the synthesis of nanostructured Fe3S4 from deep eutectic solvents via a one-step solvothermal method. The as-obtained Fe3S4 catalyst was capable of electrochemically reducing N2 to NH3 under ambient conditions, and exhibits a high NH3 yield (75.4 µg h-1 mg-1cat.) and faradaic efficiency (6.45%) at -0.4 V vs. a reversible hydrogen electrode.

Neuronal damage in hippocampal subregions induced by various durations of transient cerebral ischemia in gerbils using Fluoro-Jade B histofluorescence.

Although there are many studies on ischemic brain damage in the gerbil, which is a good model of transient cerebral ischemia, studies on neuronal damage according to the duration of ischemia-reperfusion (I-R) time are limited. We carried out neuronal damage in the gerbil hippocampus after various durations of I-R (5, 10, 15 and 20 min) using Fluoro-Jade B (F-J B, a maker for neuronal degeneration) histofluorescence as well as cresyl violet (CV) staining. The changes of CV positive ((+)) neurons were well detected in the hippocampal CA1 region, not in the other regions. F-J B histofluorescence staining showed apparent neuronal damage in all the hippocampal subregions. In the CA1, most of the pyramidal neurons of the stratum pyramidale (SP) were stained with F-J B (about 100/mm(2) in a section), and F-J B(+) neurons in the other ischemia-groups were not changed. In the CA2, a few F-J B(+) neurons were detected in the SP of the 5 min ischemia-group, and F-J B(+) neurons were gradually increased with the longer time of ischemia: in the 20 min ischemia-group, the mean number of F-J B(+) neurons was about 85/mm(2) in a section. In the CA3, some F-J B(+) neurons were observed only in the SP of the 20 min ischemia-group. In the dentate gyrus, some F-J B positive neurons were detected only in the polymorphic layer (PL) of the 5 min ischemia-group, and the number of F-J B(+) neurons were gradually increased with the longer ischemic time. Our findings indicate that F-J B histofluorescence showed a very high quality of neuronal damage in all the hippocampal subregions.

Neuroradiologic and neurophysiologic findings of neuralgic amyotrophy.

OBJECTIVE: Neuralgic amyotrophy (NA) is a distinct clinical syndrome that is characterized by the acute onset of shoulder and arm pain, weakness, and sensory loss. The purpose of this study was to assess the clinical characteristics of NA and to determine appropriate diagnostic modalities. METHODS: We reviewed the medical and radiologic records of 10 patients diagnosed with NA retrospectively. Neurophysiologic studies were performed in all patients and magnetic resonance neurography was performed in the last three patients. RESULTS: A total of 10 patients were enrolled in our study. All patients had clinical findings compatible with NA. The most common clinical presentation was severe shoulder pain and weakness in seven patients (70%). Neurophysiologic study results were abnormal in all patients. Brachial plexus magnetic resonance neurography showed that the affected brachial plexus showed a thickened and hyper-intense trunk. All patients were managed conservatively with analgesics and physical therapy. The pain and paralysis of all patients improved clinically within 6 months of the initiation of treatment. CONCLUSION: NA is a rare disease but the symptoms of NA can mimic those of other diseases. Neurophysiologic studies and magnetic resonance neurography are extremely useful tools for the diagnosis of NA.

Posterior cervical fixation with nitinol shape memory loop in the anterior-posterior combined approach for the patients with three column injury of the cervical spine : preliminary report.

OBJECTIVE: The authors reviewed clinical and radiological outcomes in patients with three column injury of the cervical spine who had undergone posterior cervical fixation using Nitinol shape memory alloy loop in the anterior-posterior combined approach. MATERIALS: Nine patients were surgically treated with anterior cervical fusion using an iliac bone graft and dynamic plate-screw system, and the posterior cervical fixation using Nitinol shape memory loop (Davydovtrade mark) at the same time. A retrospective review was performed. Clinical outcomes were assessed using the Frankel grading method. We reviewed the radiological parameters such as bony fusion rate, height of iliac bone graft strut, graft subsidence, cervical lordotic angle, and instrument related complication. RESULTS: Single-level fusion was performed in five patients, and two-level fusion in four. Solid bone fusion was presented in all cases after surgery. The mean height of graft strut was significantly decreased from 20.46+/-9.97 mm at immediate postoperative state to 18.87+/-8.60 mm at the final follow-up period (p<0.05). The mean cervical lordotic angle decreased from 13.83+/-11.84 degrees to 11.37+/-6.03 degrees at the immediate postoperative state but then, increased to 24.39+/-9.83 degrees at the final follow-up period (p<0.05). There were no instrument related complications. CONCLUSION: We suggest that the posterior cervical fixation using Nitinol shape memory alloy loop may be a simple and useful method, and be one of treatment options in anterior-posterior combined approach for the patients with the three column injury of the cervical spine.