Chloride Anions Research Articles

The influence of carbon nanotubes and exfoliated graphite nanoplatelets modified by phosphonium‐based ionic liquids on polyurethane composites

AbstractThe effect of the non‐covalent modification of carbon nanotubes (CNTs) and exfoliated graphite nanoplatelets (xGnP) with phosphonium‐based ionic liquids (ILs) on the polyurethane (PU) matrix was investigated. The two ILs used in this work were trihexyl(tetradecyl)phosphonium chloride (IL 101) and trihexyl(tetradecyl) phosphonium dicyanamide (IL 105). The electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of PU/CNTs and PU/xGnP composites was strongly influenced upon the loading and dispersion of the conductive fillers in the polymer matrix, as well as the amount and the chemical nature of IL. PU/IL‐xGnP and PU/IL‐CNTs show higher electrical conductivity and EMI SE values when compared to those composites comprising PU matrix with non‐modified fillers. Furthermore, the composites containing modified fillers with IL105 exhibited higher electrical conductivity and EMI SE values than those with IL101. This behavior was due to the better interaction of the dicyanamide counter anion (IL 105), which interacts more efficiently with the PU matrix than the chloride anion (IL 101). The hybrid composites (PU/IL‐CNT/IL‐xGnP) displayed higher electrical conductivity and EMI SE than those found for hybrid composites without ILs. Hybrid composite with a proportion of 75/25 of CNT/xGnP modified with IL 105, displayed EMI SE values adequate for commercial applications. These results highlight that these hybrid composites containing CNT/xGnP modified with trihexyl(tetradecyl) phosphonium dicyanamide are promising materials for electromagnetic shielding.

Molecular structure, as well as optical and magnetic properties, of coordination complexes comprising the organic dye flavanthrone with transition metals (MnII, CrIII, CrIV) and lanthanides (DyIII, GdIII)

The reduction of the organic dye flavanthrone (Vat Yellow 1) to the dianion state in the presence of metal-containing compounds yields coordination complexes in which two metal fragments coordinate to flavanthrone dianions to form short M − O bonds. Flavanthrone dianion coordinates to two manganese(II) acetylacetonate units in {flavanthrone⋅[MnII(acac)2]2}2− (1) with an average Mn–O bond length of 2.048(3) Å. Two dysprosium(III) or gadolinium(III) 2,2,6,6-tetramethyl-3,5-heptanedionate (TMHD) units form longer M − O bonds in {cryptand(Cs+)}2{flavanthrone⋅[DyIII(TMHD)3]2}2− (2) and {cryptand(K+)}2{flavanthrone⋅[GdIII(TMHD)3]2}2−⋅2C6H4Cl2⋅ 2C6H14 (3), with bond lengths of 2.192(2) and 2.241(4) Å, respectively. Furthermore, the utilization of decamethylchromocene as a reductant yields the unusual neutral {(flavanthrone2−)⋅[Cp*CrIII(acac)]2} comprising acac anion (4) and {(flavanthrone2−)⋅[Cp*CrIVCl2]2} comprising two chloride anions (5). Both have zwitter-ionic nature in which negative charge of flavanthrone dianions is compensated by chromium countercations. They coordinate to two chromium-containing units with short Cr–O bonds of 1.937(2) and 1.962(5) Å, respectively. The formation of flavanthrone dianions in 1–5 is confirmed by their optical spectra, the disappearance of the bands corresponding to the C=O vibrations in the infrared spectra of the complexes, and the elongation of the carbon–oxygen bonds during the formation of 1–5. The formation of binuclear, paramagnetic species with the flavanthrone dianions induces weak antiferromagnetic couplings between the paramagnetic centers because the flavanthrone dianions are diamagnetic. Stronger couplings with exchange parameters of −0.44 and −0.55 cm−1 were observed for the chromium ions bearing the shortest M − O bonds for 5 and 4, respectively. Conversely, MnII and lanthanides (GdIII, DyIII) comprising longer M − O bonds exhibit smaller J values (close to zero in 3 or equal to −0.026 and −0.05 cm−1 in 2 and 1, respectively). The complexes comprising MnII, GdIII, and CrIII display electron paramagnetic resonance (EPR) signals. The signal from MnII is approximated considering that the exchange interaction between the two MnII ions is −0.05 cm−1. Well resolved zero-field splitting (ZFS) is displayed; it facilitates the determination of the positive ZFS parameter, D, of +0.83 cm−1 and the unusually high E value, +0.62 cm−1. The spectrum of 3 comprising two GdIII ions containing 12 lines was approximated with D and E values of −0.083 and −0.021 cm−1, respectively. The odd-spin CrIII (S = 3/2) display a broad, asymmetric EPR signal at g = 3.77 without ZFS, whereas the even-spin CrIV is EPR-silent. Taken together, this study reveals that the dianions of organic dyes represent promising bidentate ligands for preparing coordination complexes with paramagnetic d- and f-block metal ions.

Molecular Switching through Chalcogen-Bond-Induced Isomerization of Binuclear (Diaminocarbene)PdII Complexes

Binuclear diaminocarbene complexes, which form as a regioisomer mixture in the reaction between isocyanide–palladium(II) complex cis-[PdCl2(CNXyl)2] and 1,3-thiazol-2-amine, are able to exchange an anionic chloride ligand with other halides, such as Br or I. This process also affords binuclear complexes as mixtures of kinetically and thermodynamically controlled regioisomers. In CDCl3 solutions, we observed interconversion of kinetically and thermodynamically controlled regioisomers. The results of the DFT calculations revealed that in CHCl3 solution, each pair of the isomers exhibited two different types of chalcogen bonding such as S···X or S···N; the presence of CBs for two complexes in the solid state was also proven through X-ray crystallographic study. Based on the combined experimental and theoretical data, it could be concluded that thermodynamic favorability for the formation of thermodynamically controlled regioisomers increases in the Cl < Br ≈ I row and correlate well with the energy difference between S···N and S···X (X = Cl, Br, I) chalcogen bonds in kinetically and thermodynamically controlled products. This means that it is possible to change the structure of metallocycles in binuclear diaminocarbene complexes by simply replacing one halide ligand with another.

Analysis of Fe2+ and Mn2+ ions in DES and water: A theoretical study using molecular dynamic simulations, QTAIM and NCI-RDG

This work was essential to analyze the behavior of Fe2+ and Mn2+ ions in water and deep eutectic solvent (DES) based on choline chloride and ethylene glycol (1ChCl:2EG (choline chloride and ethylene glycol, DES)) to evaluate the electrodeposition of metallic ions. Due to their low toxicity, high solubility, biodegradability and thermal stability, DES have shown promise as alternatives to traditional solvents such as water in various applications, including biological studies. They also dissolve insoluble substances in other types of solvents, working from the purification of chemicals to the manufacture of semiconductor devices. Water, choline and ethylene glycol molecules were optimized by Density Functional Theory (DFT) through B3LYP/6–311 +G(d,p) model implemented with the Gaussian 09 W software. Molecular Dynamics (MD) simulations were performed by GROMACS software 2020.04 in a cubic box of dimensions 8 nm × 8 nm × 8 nm. Quantum Theory of Atoms in Molecules (QTAIM) and analysis of Non-covalent Interactions (NCI) used Multiwfn 3.8 software. The preliminary results of MD simulations showed that gradually adding water increased the interaction between the metal center and water. Fe2+ and Mn2+ ions were placed in water (OW) and 1ClCh:2EG, indicating that the interaction between the cations and the chloride anion in DES was strong, followed by the ethylene glycol molecules (O1, O2). In the presence of water, however, Fe-OW and Mn-OW interactions were more substantial in all systems, either with the ions alone or in a mixture. Electrostatic forces acting on the electrons in the last filled layer of the iron atom provided the formation of shorter and stronger bonds than the Mn2+ ions. When placed in a 1:1 equimolar mixture, they showed little difference from when they were isolated. Thus, the Mn-Cl interaction was more significant in the presence of a eutectic solvent than the Fe-Cl interaction. QTAIM analysis showed for the FeDES and MnDES systems that the Electron Localization Function (ELF) values increased for the Fe-(O1, O2) and Mn-(O1, O2) interactions but decreased for the Fe-Cl and Mn-Cl interactions in the metal mixture. It revealed strong hydrogen bonding interactions between the water molecules, Fe2+ and Mn2+, which may affect their chemical reactivity, as the Fe-Cl interaction in DES was stronger than Fe-Cl in any water. The Laplacians of the electronic densities were positive, and so were the ELF values, indicating a predominance of non-covalent interactions of the van der Waals forces type. Considering the two metal ions alone, in the presence of DES, the interaction strength followed Fe-Cl > Mn-Cl > Fe-(O1, O2) > Mn-(O1, O2). In the mixture, Fe-Mn followed the pattern Mn-Cl > Fe-Cl > Fe-(O1, O2) > Mn-(O1, O2). Thus, comparing the 3 systems, the interaction strength was Fe-Cl > Mn-Cl > Mn-Clmixture > Fe-Cl mixture e Fe-(O1, O2) mixture > Fe-(O1, O2) > Mn-(O1, O2)mixture > Mn-(O1, O2). The interaction strength for the systems with water was Fe-Clmixture > Fe-Cl > Mn-Cl > Mn-Clmixture. However, for the interaction with OW, the observed behaviors were: W300, Mn-OW > Fe-OWmixture > Mn-OWmixture > Fe-OWmixture; W600, Mn-OWmixture > Fe-OWmixture > Mn-OW > Fe-OW; W900, Mn-OW > Fe-OW > Mn-OWmixture > Fe-OWmixture; W1200, Mn-OW > Mn-OWmixture > Fe-OWmixture > Fe-OWmixture; W5580, Mn-OW > Fe-OW > Mn-OWmixture > Fe-OWmixture. The mixtures in the 1:1 molar ratio of the cations presented a little discrepant from their isolated ions, suggesting a new approach to observing the behavior of these systems and the coordination possibilities. One of the prospects for expanding the study will be temperature variation, modification of metal ions and molar proportions, and the effects of these changes.

Tricine-supported polyoxo(alkoxo)lanthanide cluster {Ln15} (Ln = Eu, Gd, Tb) with magnetic refrigerant and fluorescent properties

A family of polyoxo(alkoxo)lanthanide cluster {Ln₁₅} [Ln = Eu (<strong>1</strong>), Gd (<strong>2</strong>), Tb (<strong>3</strong>)] was successfully isolated via the simple hydrolysis reaction of lanthanide metal ions in the presence of tricine ligand. X-ray diffraction analyses revealed the {Ln₁₅} display a wheel-like structure with a <em>µ</em>₅-chloride anion as template. Interestingly, each analogue shows distinctive function based on the different Ln(III) ions. The complexes <strong>1</strong> and <strong>3</strong> in solid state emitted the characteristic fluorescence of Eu(III) or Tb (III). The fluorescence lifetimes of ⁵<em>D</em>₀ excited state for <strong>1</strong> and ⁵<em>D</em>₄ excited state for <strong>3</strong> were tested and the values were 890 and 250 μs, respectively. For gadolinium analogue <strong>2</strong>, it exhibits magneto-caloric effect at ultralow temperatures with a maximum −Δ<em>S</em>_m value of 29.9 J·kg⁻¹·K⁻¹ at 3 K and 7 T.

Insight into direct phosphorus release from simulated wastewater ferric sludge: Influence of physiochemical factors

Phosphorous recovery from chemical phosphorus removal (CPR) plants is limited. CPR plants that use iron salts for phosphorous removal generate iron phosphate (Fe-P) rich sludge. This study investigates the influence of pH and competing anions (chloride), on phosphorus and soluble iron release from lab simulated Fe-P sludge. Factors influencing recovery, such as sludge age and Fe/P molar ratio are also investigated. Results showed that alkaline treatment of Fe-P sludge was not effective in releasing Fe (<3%) but effective in releasing P, particularly at controlled pH value of 10 where the %P release was (90 ± 2%). Sludge ageing time did not affect P release from Fe-P sludge at ages less than 5 days. However, a remarkable decrease in %P release (i.e., 50% reduction) was observed at ages of 9 and 11 days for pH values of 9–10. Arsenic extraction of exchangeable surface bound P from Fe-P sludge and surface area determination of hydrous ferric oxide (HFO) under different aging times supported qualitatively the internalization of surface bound P during aging, which is a proposed mechanism responsible for the decrease in P release for older sludge. Chloride effect in releasing P from Fe-P sludge was negligible. The reduction in P release by aging was best described by a zero-order kinetic model. Modeling with the PHREEQC geochemical software did not always agree with the measured release of phosphorus from the Fe-P sludge. PHREEQC assumes all surface sites for phosphorus are exchangeable and has no mechanism to represent phosphorus trapped within HFO particles.

Effect of solvent and auxiliary ligand on catecholase activities of Mn(III) complexes: A comparative study

A mononuclear Mn(III) complex with composition [MnIIIL(Cl)] (1) has been utilized to prepare two new complexes, [MnIIIL(N3)(CH3OH)] (2) and [MnIIIL(μ1,3-NCS)]n (3), by substitution of the auxiliary ligand. The ligand utilized for preparation of 1 is a Schiff base (H2L), obtained by 2:1 condensation of 3-Chlorosalicylaldehyde and ethylene diamine in methanol. The chloride anion, present in the coordination sphere of the central metal ion in 1 has been replaced by two other auxiliary ligands, azide and thiocyanate, in 2 and 3, respectively. All of the three complexes behaved as bio-functional models of catechol oxidase toward oxidation of 3,5-di-tert butyl catechol (3,5-DTBC). A detailed kinetic investigations were carried out for 2 and 3 in methanol, acetonitrile and N,N′-Dimethyl formamide (DMF) separately and the corresponding turn-over numbers have been determined. The ESI-MS spectra of the substrate-catalyst mixtures in acetonitrile and methanol confirmed formation of catecholate bound Mn(III) intermediate in the mass spectral time scale. The progress of the catechol oxidation was monitored by 1H-NMR spectroscopy with the reaction mixtures containing complex-substrate ratio at 1:20 after stirring in acetonitrile as well as methanol at room temperature in open air. NMR spectral data confirmed completion of the process in 90 minutes and 45 minutes for 2 and 3, respectively. Notably, in absence of any of these complexes, aerobic oxidation of 3,5-DTBC to the corresponding quinone is negligible even after twenty four hours of mixing in the same solvent. This observation is a clear indicative of high catalytic efficiencies of the prepared complexes.

Understanding the mechanisms of anisotropic dissolution in metal oxides by applying radiolysis simulations to liquid-phase TEM

Iron-based redox-active minerals are ubiquitous in soils, sediments, and aquatic systems. Their dissolution is of great importance for microbial impacts on carbon cycling and the biogeochemistry of the lithosphere and hydrosphere. Despite its widespread significance and extensive prior study, the atomic-to-nanoscale mechanisms of dissolution remain poorly understood, particularly the interplay between acidic and reductive processes. Here, we use insitu liquid-phase-transmission electron microscopy (LP-TEM) and simulations of radiolysis to probe and control acidic versus reductive dissolution of akaganeite (β-FeOOH) nanorods. Informed by crystal structure and surface chemistry, the balance between acidic dissolution at rod tips and reductive dissolution at rod sides was systematically varied using pH buffers, background chloride anions, and electron beam dose. We find that buffers, such as bis-tris, effectively inhibited dissolution by consuming radiolytic acidic and reducing species such as superoxides and aqueous electrons. In contrast, chloride anions simultaneously suppressed dissolution at rod tips by stabilizing structural elements while promoting dissolution at rod sides through surface complexation. Dissolution behaviors were systematically varied by shifting the balance between acidic and reductive attacks. The findings show LP-TEM combined with simulations of radiolysis effects can provide a unique and versatile platform for quantitatively investigating dissolution mechanisms, with implications for understanding metal cycling in natural environments and the development of tailored nanomaterials.

Synthesis, characterization, biological and theoretical studies of a new Pd(II) complex of drug carvedilol: Strong anticancer activity against several cell lines

In this study, a new Pd(II) complex of the drug carvedilol (CAR), [Pd(CAR)2Cl2] (PdCAR), was synthesized and characterized using X-ray crystal structure determination, CHN elemental analysis, and FT-IR, 1H NMR and UV–Vis spectroscopies. The crystal structure of the above complex shows that the Pd atom lies on a center of symmetry and is coordinated by two ligands (CAR) and by two chloride anions in a square planar arrangement. It means that each carvedilol ligand is coordinating to the Pd atom in a monodentate fashion, via the aliphatic nitrogen atom. Theoretical studies showed that the nature of the bond between PdCl2 and two carvedilol ligands, similar to that between PdCl2 and two dimethylamine (DMA) ligands, is mainly electrostatic. Interestingly, the CAR−PdCl2 bond is stronger than the DMA−PdCl2 bond. The UV–Vis and NMR studies indicate that the PdCAR complex is stable in solution. The DNA interaction studies were performed using the molecular docking simulation. The results indicated that the binding affinity of the PdCAR for B-DNA is higher than that of the CAR. Furthermore, the cytotoxicity effects of CAR, PdCAR and cisplatin (CIS) against MCF-7, HepG2, SW-480, CT-26 and HEK-293 cell lines were also evaluated and compared by MTT assay. The results showed that the cytotoxicity of both CAR and PdCAR on the above cell lines in all cases, except MCF-7, is higher than that of CIS.

Conformationally Flexible Cleft Receptor for Chloride Anion Transport.

The design and synthesis of a cleft-shaped bis-diarylurea receptor for chloride anion transport is reported in this work. The receptor is based on the foldameric nature of N,N'-diphenylurea upon its dimethylation. The bis-diarylurea receptor exhibits a strong and selective affinity for chloride over bromide and iodide anions. A nanomolar quantity of the receptor efficiently transports the chloride across a lipid bilayer membrane as a 1:1 complex (EC50 = 5.23 nm). The work demonstrates the utility of the N,N'-dimethyl-N,N'-diphenylurea scaffold in anion recognition and transport.

PROPERTIES OF NANOSTRUCTURED COMPOSITES OF POLY(VINYLIDENE FLUORIDE) WITH DOPED POLY(3-METHYLTHIOPHENE)

The combination of properties of intrinsically conducting polymers (ICPs) and functional nanostructured template materials opens up prospects for their use in various fields, ranging from bioelectronics to sensors and energy conversion. Successful combinations solve one of the important drawbacks of many ICPs, created by their insolubility and infusibility, and help to achieve their full potential in thermally processable materials. When developing such hybrid materials, it is necessary to take into account the sensitivity of ICP properties to interphase interactions due to extended π-conjugation in these polymers. However, this aspect of ICP-based nanocomposites has not been sufficiently studied yet. In this paper we investigate the effect of template submicron poly(vinylidene fluoride) (PVDF) particles and the nature of the dopant on properties of poly(3-methylthiophene) (P3MT) precipitated as the shell at the PVDF core surface in the course of the 3MT oxidative polymerization. For this purpose, we compare the properties of P3MT phase of the composites with the properties of the neat P3MT doped with dodecylbenzenesulfonate (DBS), perfluorooctanoate (PFO) and chloride anions. In the formed composite core-shell particles the P3MT is in the form of asymmetric nanoparticles which are localized almost exclusively at the surface of PVDF particles. According to the conjugation length, neat polymers form the following series: P3MT-Cl &gt; P3MT-DBS &gt; P3MT-PFO as evidenced by the IR spectral analysis. In their composites the conjugation length of P3MT doped with Cl- does not change noticeably, while for the DBS and PFO anions cases it increases and for the DBS case it exceeds that of Cl- case. X-ray phase analysis showed an increase in the degree of crystallinity of P3MT-Cl and P3MT-DBS phases in the composition of composites by 1.4 and 1.3 times relative to the corresponding values for the neat doped P3MTs. Such an increase can be caused by the influence of the local electric field of the dipoles of the electroactive part of the crystalline phase of PVDF (β- and γ-phase) on the spatial arrangement of charged P3MT macromolecules formed on the surface of PVDF. Thermogravimetric studies show an increase in the thermal stability of the doped P3MT phase of nanocomposites while conductivity measurements reveal a significant effect of the nature of the dopant anion.

Giant Negative Thermopower Enabled by Bidirectionally Anchored Cations in Multifunctional Polymers.

The lack of high-quality ionic thermoelectric materials with negative thermopowers has stimulated scientists' broad research interest. The effective adjustment of the interaction between ions and a polymer network is an important way to achieve high-quality ion thermoelectric properties. Integrating different types of ion-polymer interactions into the same thermoelectric device seems to lead to unexpected gains. In this work, we propose a strategy for bidirectionally anchoring cations to synergistically generate a giant negative thermopower and high ionic conductivity. This is mainly achieved through synergistic ion-polymer coordination and Coulomb interactions. An ionic thermoelectric material was prepared by infiltrating a polycation electrolyte [poly(diallyldimethylammonium chloride)] with CuCl2 into the poly(vinyl alcohol)-chitosan aerogel. The confinement effect of copper-coordinated chitosan on cations, the repulsive property of the polycationic electrolyte on cations, and the unique chemical configuration of a transition metal chloride anion ([CuCl4]2-) are the fundamental guarantees for achieving a thermopower of -28.4 mV·K-1. Moreover, benefiting from the high charge density of the polycationic electrolyte, we obtain an ionic conductivity of 40.5 mS·cm-1. These findings show the application prospect of synergistic different types of ion-polymer interactions in designing multifunctional ionic thermoelectric materials.

Investigation the effect of water addition on intermolecular interactions of fatty acids-based deep eutectic solvents by molecular dynamics simulations

In this work, we focused on the interaction between hydrogen bond acceptor (HBA) and hydrogen bond doner (HBD) in the binary mixtures. The results showed that Cl− anion plays a key role in the formation of DESs. Also, the structural stability of deep eutectic solvents based on fatty acids (FAs) and choline chloride (Ch+Cl−) at different ratios was investigated in water using molecular dynamics simulations. We observed that the interaction between the chloride anion and the hydroxyl group of the cation leads to the transition of HBA to the water-rich phase. These atomic sites have important rule in the stability of the eutectic mixtures based on FAs and Cl− anion. However, it seems that the binary mixtures with the mole percent at 30% of [Ch+Cl−] and 70% of FAs have more stability than other ratios.

Investigation of N,N′‐Disulfopiperazinium Chlorometallates of Fe(III), Ni(II) and Co(II) as Hybrid Catalysts for the Synthesis of 1,2‐Dihydroquinazoline Derivatives

AbstractThree organic salts of N,N′‐disulfopiperazinium cation with complex metal chloride anions of Fe(III), Ni(II) and Co(II) cations were developed as Brønsted‐Lewis acidic hybrid materials in solid state. Their structural compositions were established by FT‐IR, UV‐Visible, SEM, EDX, Powder XRD and Raman techniques. Thermogravimetric analyses showed removal of physisorbed water around 100 °C for Fe(III) salt in contrast to 150–170 °C for Ni(II) &amp; Co(II) organic salts for strongly bound water molecules in highly crystalline state. Their Brønsted acidities were determined from comparative UV‐visible spectra of 4‐nitroaniline in water in presence of the halometallates while Lewis acidity strength was observed via FT‐IR spectra of these salts in presence of pyridine as probe molecule. The catalytic activity of these acidic organic salts was investigated for three‐component synthesis of 1,2‐dihydroquinazolines as recyclable heterogeneous catalysts.

Synthesis and structure of two novel trans-platinum complexes.

Here for the first time the synthesis and characterization of two new trans-platinum complexes, trans-[PtCl2{HN=C(OH)C6H5}2] (compound 1) and trans-[PtCl4(NH3){HN=C(OH)tBu}] (compound 2) [with tBu = C(CH3)3] are described. The structures have been characterized using nuclear magnetic resonance spectroscopy and X-ray single-crystal diffraction. In compound 1 the platinum cation, at the inversion center, is in the expected square-planar coordination geometry. It is coordinated to two chloride anions, trans to each other, and two nitrogen atoms from the benzamide ligands. The van der Waals interactions between the molecules produce extended two-dimensional layers that are linked into a three-dimensional structure through π...π intermolecular interactions. In compound 2 the platinum cation is octahedrally coordinated by four chloride anions and two nitrogen atoms from the pivalamide and ammine ligands, in trans configuration. The molecular packing is governed by intermolecular hydrogen bonds and van der Waals interactions.

Room temperature phosphorescence from natural wood activated by external chloride anion treatment

Producing afterglow room temperature phosphorescence (RTP) from natural sources is an attractive approach to sustainable RTP materials. However, converting natural resources to RTP materials often requires toxic reagents or complex processing. Here we report that natural wood may be converted into a viable RTP material by treating with magnesium chloride. Specifically, immersing natural wood into an aqueous MgCl2 solution at room temperature produces so-called C-wood containing chloride anions that act to promote spin orbit coupling (SOC) and increase the RTP lifetime. Produced in this manner, C-wood exhibits an intense RTP emission with a lifetime of ~ 297 ms (vs. the ca. 17.5 ms seen for natural wood). As a demonstration of potential utility, an afterglow wood sculpture is prepared in situ by simply spraying the original sculpture with a MgCl2 solution. C-wood was also mixed with polypropylene (PP) to generate printable afterglow fibers suitable for the fabrication of luminescent plastics via 3D printing. We anticipate that the present study will facilitate the development of sustainable RTP materials.

Chloride salt of oligourea ligand: Synthesis, crystal structure, thermal analyses, and chloride anion binding properties

A novel oligourea ligand L, C33H27N11O8, was synthesized by the isocyanate method using 3, 5-diaminopyridine as the initial reactant. The chloride salt 1, TBA2(LCl2)·acetone, was prepared by the liquid-phase diffusion method of ligand L with tetrabutylammonium chloride (TBACl) at room temperature. The ligand L and salt 1 were characterized by 1H NMR, elemental analysis and Fourier transform infrared spectroscopy (FTIR). X-ray single crystal diffraction analysis showed that in the structure of salt 1, two ligands L formed a dimeric species with two appropriate cavities each trapping two chloride anions by multiple N-H···Cl hydrogen bonds. As a structural unit, the dimer was linked to a one-dimensional hydrogen bond chain through the C-H···O hydrogen bond interactions, which was further extended into two-dimensional network structures by C-H···O and C-H···Cl hydrogen bonds. Thermal decomposition properties of the ligand and salt 1 under nitrogen were studied by the TG-DTG method, and the apparent activation energy (Ea) of the main decomposition process was calculated. Furthermore, the selectivity of ligand L to different anions and the binding properties of Cl− anion were investigated by the method of the UV/Vis spectroscopy.

Enhanced Electrochemical Properties of Cobalt by Varying the Ethylene Glycol - Choline Chloride Composition in a Deep Eutectic Solvent Mixture

The increased demand for portable electronic devices and electric vehicles has resulted in an exponential increase in lithium-ion battery (LIB) waste, and becoming in turn an important secondary source for critical metals. Electrowinning is a commonly used method to recover base and precious metals from a solution, which can also be used to recover valuable metals from spent LIBs. This study unveiled the cobalt electrochemical recovery using model Co sources in increasing amounts of ethylene glycol (EG), 67 molar %, 82 molar % and 100 molar %, in a mixture with choline chloride. The electrochemical results show that increasing the amount of EG together with a small concentration of sulfate anions, in conjunction with chloride anions, in the solution mixture favours the reduction of Co2+. This improved electrochemistry seems to be related to changes of Co2+ speciation easing the reduction process. Additionally, the nature of the Co salt has a significant impact on the recovery efficiency, morphology, and purity of the Co electrodeposit. This work will underpin the science to design safe electrolyte mixtures to enhance the electrochemical recovery of Co2+ in solution from secondary sources.

Selective Separation of Singly Charged Chloride and Dihydrogen Phosphate Anions by Electrobaromembrane Method with Nanoporous Membranes.

The entrance of even a small amount of phosphorus compounds into natural waters leads to global problems that require the use of modern purification technologies. This paper presents the results of testing a hybrid electrobaromembrane (EBM) method for the selective separation of Cl- (always present in phosphorus-containing waters) and H2PO4- anions. Separated ions of the same charge sign move in an electric field through the pores of a nanoporous membrane to the corresponding electrode, while a commensurate counter-convective flow in the pores is created by a pressure drop across the membrane. It has been shown that EBM technology provides high fluxes of ions being separated across the membrane as well as a high selectivity coefficient compared to other membrane methods. During the processing of solution containing 0.05 M NaCl and 0.05 M NaH2PO4, the flux of phosphates through a track-etched membrane can reach 0.29 mol/(m2×h). Another possibility for separation is the EBM extraction of chlorides from the solution. Its flux can reach 0.40 mol/(m2×h) through the track-etched membrane and 0.33 mol/(m2×h) through a porous aluminum membrane. The separation efficiency can be very high by using both the porous anodic alumina membrane with positive fixed charges and the track-etched membrane with negative fixed charges due to the possibility of directing the fluxes of separated ions in opposite sides.

Quality assessment of non-roof harvested rainwater in industrial layouts of Enugu, South East Nigeria

Non-roof harvested rainwater was studied in Enugu industrial layouts of Emene and Iva Valley to determine the quality of the water. The determination was based on physicochemical parameters and concentration of 7 heavy metals, namely copper (Cu), chromium (Cr), nickel (Ni), manganese (Mn), zinc (Zn), lead (Pb) and cadmium (Cd). The physicochemical parameters of the rainwater: pH, colour, turbidity, total dissolved solids, conductivity were determined using Hanna water quality checker, and the anions nitrate, sulphate, chloride and phosphate were analysed in accordance to standard methods. The concentrations of Cu, Cr, Ni, Mn, Zn, Pb and Cd were determined using FS240 Agilent Atomic Absorption Spectrophotometer. The mean values (mg/l) of the metals: Cu, Cr, Ni, Mn, Zn, Pb and Cd in Emene sample are as follows: 0.12 ± 0.01, 0.10 ± 0.02, 0.37 ± 0.02, 0.03 ± 0.01, 0.15 ± 0.01, 0.58 ± 0.11 and 0.17 ± 0.07, while Iva Valley sample recorded 0.08 ± 0.01, 0.04 ± 0.01, 0.82 ± 0.06, 0.09 ± 0.02, 0.26 ± 0.01, 0.48 ± 0.04 and 0.31 ± 0.08, respectively. Some of these values are within or above the standard limit of World Health Organization (WHO) and Nigeria Standard for Drinking Water Quality (NSDWQ). It is important to note that these metals are toxic, persistence and have the potential to bioaccumulate. Therefore, non-roof harvested rainwater is not ready to consume water without some form of treatment. Monitoring, treatment and awareness on the harvesting and use of rainwater should be emphasized.