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1.
Methods Mol Biol ; 2571: 105-114, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36152154

RESUMO

The simultaneous analysis of cationic and anionic metabolites using capillary electrophoresis-mass spectrometry (CE-MS) has been considered challenging, as often two different analytical methods are required. Although CE-MS methods for cationic metabolite profiling have already shown good performance metrics, the profiling of anionic metabolites often results in relatively low sensitivity and poor repeatability caused by problems related to unstable electrospray and corona discharge when using reversed CE polarity and detection by MS in negative ionization mode. In this protocol, we describe a chemical derivatization procedure that provides a permanent positive charge to acidic metabolites, thereby allowing us to profile anionic metabolites by CE-MS using exactly the same separation conditions as employed for the analysis of basic metabolites. The utility of the overall approach is demonstrated for the analysis of energy metabolism-related metabolites in low numbers of HepG2 cells.


Assuntos
Eletroforese Capilar , Espectrometria de Massas por Ionização por Electrospray , Animais , Ânions , Cátions , Eletroforese Capilar/métodos , Mamíferos , Espectrometria de Massas por Ionização por Electrospray/métodos
2.
Molecules ; 27(17)2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-36080204

RESUMO

Adsorption abilities of weakly (Purolite A830), weakly basic/chelating (Purolite S984), and strongly basic (Lewatit MonoPlus SR7, Purolite A400TL, Dowex PSR2, Dowex PSR3) ion exchange resins of different functional groups and microporous Lewatit AF5 without functional groups towards vanadium(V) ions were studied in batch and column systems. In the batch system, the influence of the sorbent mass (0.01-0.1 g), pH (2-10), the phase contact time (1-1440 min),and the initial concentration (5-2000 mg/L) were studied, whereas in the column system, the initial concentrations (50, 100, and 200 mg/L) with the same bed volume and flow rate (0.4 mL/min) were studied. Desorption agents HCl and NaOH of 0.1-1 mol/L concentration were used for loaded sorbent regeneration. The pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models as well as the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models were used to describe kinetic and equilibrium data to acquire improved knowledge on the adsorption mechanism. The desorption efficiency was the largest using 0.5 mol/L NaOH for all sorbents under discussion. Purolite S984, Purolite A830, and Purolite A400TL, especially Purolite S984, are characterized by the best removal ability towards vanadium(V) from both model and real wastewater.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Adsorção , Ânions , Concentração de Íons de Hidrogênio , Cinética , Hidróxido de Sódio , Soluções , Termodinâmica , Vanádio , Água , Poluentes Químicos da Água/química
3.
Molecules ; 27(17)2022 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-36080470

RESUMO

Besides their extremely useful properties as solvent, ionic liquids (ILs) are now considered to be highly instructive tools for enhancing the rates of chemical reactions. The ionic nature of the IL anion and cation seems to be the origin of this fascinating function of ILs as organocatalyst/promoter through their strong Coulombic forces on other ionic species in the reaction and also through the formation of hydrogen bonds with various functional groups in substrates. It is now possible to tailor-make ILs for specific purposes as solvent/promoters in a variety of situations by carefully monitoring these interactions. Despite the enormous potentiality, it seems that the application of ILs as organocatalysts/promoters for chemical reactions have not been fully achieved so far. Herein, we review recent developments of ILs for promoting the nucleophilic reactions, focusing on fluorination. Various aspects of the processes, such as organocatalytic capability, reaction mechanisms and salt effects, are discussed.


Assuntos
Líquidos Iônicos , Ânions/química , Halogenação , Ligação de Hidrogênio , Líquidos Iônicos/química , Solventes/química
4.
Anal Chim Acta ; 1227: 340329, 2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36089328

RESUMO

Considering the highly carcinogenic and mutagenic of anionic azo dyes to the environment and humans, the development of high efficiency adsorbent for them are of great significance. In this study, a novel hydroxyl-riched covalent organic framework (denoted as COF-OH), which can act as an advance adsorbent for anionic azo dyes, was fabricated for the first time. The as-prepared COF-OH demonstrated good dispersion in water, remarkable adsorption performances and good selectivity for anionic azo dyes including eriochrome black T, eriochrome blue black R and congo red. The adsorption capacities of them ranged from 90.71 to 229.12 mg g-1, and the extraction efficiencies of them (>75.91%) were much higher than other dyes (e.g. Methylene blue, direct red 80, 1.46%-39.57%). By optimizing the adsorption conditions (adsorbent dosage, adsorption time, pH, and salt concentration) and desorption conditions (desorption solvent, desorption time and desorption frequency), a dispersive micro solid-phase extraction (D-µ-SPE) method was developed. Further, coupled D-µ-SPE with HPLC-PDA analysis, an effective method was fabricated for the extraction and detection of three selected dyes. The method showed good linearity in the range of 0.1-200 µg mL-1 (R2 > 0.9966), low limits of quantification (0.10 µg mL-1-2.00 µg mL-1), low limits of detection (0.03-1.50 µg mL-1) and good precision. Finally, the COF-OH based D-µ-SPE was successfully applied to extract three selected dyes from water samples (recoveries ranged from 73.90 to 104.00%) and congo red from beverages (recoveries ranged from 81.40 to 111.80%). Besides, by using computer simulation, FT-IR and UV-vis analysis, the adsorption mechanisms of COF-OH to three selected dyes were explored preliminarily.


Assuntos
Estruturas Metalorgânicas , Adsorção , Ânions , Compostos Azo , Corantes , Simulação por Computador , Vermelho Congo , Humanos , Radical Hidroxila , Espectroscopia de Infravermelho com Transformada de Fourier , Água
5.
Sci Rep ; 12(1): 15005, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36056086

RESUMO

Electrical aspects of cell function manifest in many ways. The most widely studied is the cell membrane potential, Vm, but others include the conductance and capacitance of the membrane, the conductance of the enclosed cytoplasm, as well as the charge at the cell surface (an electrical double layer) producing an extracellular electrical potential, the ζ-potential. Empirical relationships have been identified between many of these, but not the mechanisms that link them all. Here we examine relationships between Vm and the electrical conductivities of both the cytoplasm and extracellular media, using data from a suspensions of red blood cells. We have identified linear relationships between extracellular medium conductivity, cytoplasm conductivity and Vm. This is in contrast to the standard model of a resting membrane potential which describes a logarithmic relationship between Vm and the concentration of permeable ions in the extracellular medium. The model here suggests that Vm is partially electrostatic in origin, arising from a charge imbalance at an inner electrical double-layer, acting across the membrane and double-layer capacitances to produce a voltage. This model describes an origin for coupling between Vm and ζ, by which cells can alter their electrostatic relationship with their environment, with implications for modulation of membrane ion transport, adhesion of proteins such as antibodies and wider cell-cell interactions.


Assuntos
Eritrócitos , Ânions , Cátions , Citoplasma , Condutividade Elétrica , Potenciais da Membrana/fisiologia
6.
Int J Mol Sci ; 23(17)2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36077202

RESUMO

Non-viral delivery of therapeutic nucleic acids (NA), including siRNA, has potential in the treatment of diseases with high unmet clinical needs such as acute myeloid leukaemia (AML). While cationic biomaterials are frequently used to complex the nucleic acids into nanoparticles, attenuation of charge density is desirable to decrease in vivo toxicity. Here, an anionic amphiphilic CD was synthesised and the structure was confirmed by Fourier-transform infrared spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR), and high-resolution mass spectrometry (HRMS). A cationic amphiphilic cyclodextrin (CD) was initially used to complex the siRNA and then co-formulated with the anionic amphiphilic CD. Characterisation of the co-formulated NPs indicated a significant reduction in charge from 34 ± 7 mV to 24 ± 6 mV (p < 0.05) and polydispersity index 0.46 ± 0.1 to 0.16 ± 0.04 (p < 0.05), compared to the cationic CD NPs. Size was similar, 161-164 nm, for both formulations. FACS and confocal microscopy, using AML cells (HL-60), indicated a similar level of cellular uptake (60% after 6 h) followed by endosomal escape. The nano co-formulation significantly reduced the charge while maintaining gene silencing (21%). Results indicate that blending of anionic and cationic amphiphilic CDs can produce bespoke NPs with optimised physicochemical properties and potential for enhanced in vivo performance in cancer treatment.


Assuntos
Ciclodextrinas , Leucemia Mieloide Aguda , Nanopartículas , Ânions , Cátions , Ciclodextrinas/química , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/terapia , Nanopartículas/química , RNA Interferente Pequeno/química , RNA Interferente Pequeno/genética , Espectroscopia de Infravermelho com Transformada de Fourier
7.
J Am Chem Soc ; 144(37): 16767-16772, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36070570

RESUMO

A new type of cage inherent chirality was accessed by hierarchical desymmetrization of a D3h-symmetric prismlike cage motif. The dissymmetric C3v cage precursor C1 bearing two different phloroglucinol caps was first synthesized. The subsequent progressive substitutions on the three triazine arms by different nucleophiles furnished the desired C1-symmetric inherently chiral cages C3 and C4 with rich structural diversity. Resolution of the racemic cages was achieved by chiral chromatography, and the enantiopure cages were readily obtained on the gram scale. Convenient post-synthetic transformations of the chiral cages with retention of enantiomeric purity were also realized. The absolute configuration was determined by X-ray crystallography, and a chirality descriptor was provided to define the cage chirality. With the inherently chiral array of the electron-deficient triazine surfaces constituting three individual chiral V-shaped π cavities, regio- and enantioselective anion-π binding was probed for the first time with minimum interference of other interactions. As exemplified with chiral phosphate anions (CPAs), it was found that cage (-)-C3a preferably binds (S)-CPA- in the most electron-deficient cavity through synergistic anion-π interactions with considerable chiral selectivity.


Assuntos
Fosfatos , Triazinas , Ânions/química , Floroglucinol , Estereoisomerismo
8.
J Am Chem Soc ; 144(37): 16996-17009, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36074582

RESUMO

A molecular capsule (1) consisting of two calix[4]pyrroles connected via ethylene diamide linkers has been prepared as an anion receptor. 1H NMR spectroscopic studies carried out in CD2Cl2 revealed that receptor 1 recognizes a variety of anions with different binding modes and stoichiometries. For instance, receptor 1 binds fluoride and acetate with 1:2 receptor/anion stoichiometry and other test anions with 1:1 stoichiometry in solution when their respective tetrabutylammonium (TBA+) salts were used. In contrast, with tetraethylammnium (TEA+) salts, receptor 1 forms 1:2 complexes with chloride and bromide in addition to fluoride, overcoming expected Columbic repulsions between the anions co-bound in close proximity. Receptor 1 is also able to bind oxoanions, such as oxalate (C2O42-), dihydrogen phosphate (H2PO4-), sulfate (SO42-), and hydrogen pyrophosphate (HP2O73-), in the form of 1:1 complexes as the result of presumed cooperation between the two calix[4]pyrrole subunits. The selectivity of receptor 1 for fluoride versus dihydrogen phosphate varies depending on their relative concentrations. For instance, in the presence of less than 1.0 equiv of an equimolar mixture of fluoride and dihydrogen phosphate, receptor 1 shows high selectivity for dihydrogen phosphate. In contrast, in the presence of ≥2.0 anion equiv, receptor 1 binds fluoride preferentially, forming a 1:2 complex. Moreover, when treated with F-, the preformed 1:1 H2PO4- complex of receptor 1 is converted to the corresponding 1:2 receptor/fluoride complex with the release of the prebound dihydrogen phosphate anion. As inferred from gas-phase computations, this seemingly counterintuitive behavior is rationalized in terms of the precomplexed dihydrogen phosphate serving to reduce the reorganization energy required to bind two fluoride anions. The presence of a water molecule in addition to the bound fluoride anions may also favor the formation of the 1:2 F- complex. The present study provides a new approach for fine-tuning the binding selectivity of polytopic anion receptors.


Assuntos
Calixarenos , Fosfatos , Ânions/química , Brometos , Calixarenos/química , Cloretos , Diamida , Difosfatos , Etilenos , Fluoretos , Hidrogênio , Oxalatos , Fosfatos/química , Pirróis/química , Sais , Sulfatos , Água
9.
J Chromatogr A ; 1681: 463455, 2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36075135

RESUMO

In this study, an expanded bed anion exchange in a countercurrent chromatography column (EB-CCC) technique for separation and purification of heparin, an anticoagulant and antithrombotic glycosaminoglycan, is reported for the first time. A comparative evaluation of the EB-CCC technique with the conventional fixed bed column chromatography (FBCC) revealed its effectiveness in improving adsorption at high flow rates and reducing separation time. A significantly higher maximum adsorption (91.66%) was exhibited by EB-CCC in comparison with FBCC (45.16%) at the eluent flow rate of 1 mL·min-1. Similarly, the experimental adsorption capacity of heparin was enhanced by 1.69, 2.06 and 2.58 times in the case of EB-CCC at the flow rates of 1, 2 and 5 mL·min-1, respectively. Moreover, the directly proportional amplification of double loaded resin and double column volume was demonstrated at an EB-CCC rotational speed of 300 rpm and a flow rate of 2 mL·min-1, and the experimental adsorption capacity was observed to increase from 66.42 to 136.48 mg·g-1 after amplification. Heparin purified by EB-CCC displayed higher potency (216.09 ± 11.89 IU·mg-1) as compared to FBCC (205.51 ± 7.90 IU·mg-1) and the initial crude heparin 134.17 ± 4.12 IU·mg-1. Furthermore, comparing to the purified heparin by FBCC, heparin purified by EB-CCC had low molecular weight, high FXa/FIIa, superior anticoagulation effect and enhanced suitability as an exogenous anticoagulant.


Assuntos
Distribuição Contracorrente , Heparina , Adsorção , Ânions , Anticoagulantes/farmacologia , Distribuição Contracorrente/métodos , Fibrinolíticos
10.
Molecules ; 27(18)2022 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-36144815

RESUMO

A new programed upper critical solution temperature-type thermoresponsive polymer was developed using water-soluble anionic polymer conjugates derived from polyallylamine and phthalic acid with cleavage-induced phase transition property. Intrinsic charge inversion from anion to cation of the polymer side chain is induced through a side chain cleavage reaction in acidic aqueous media. With the progress of side chain cleavage under fixed external conditions, the polymer conjugates express a thermoresponsive property, followed by shifting a phase boundary due to the change in polymer composition. When the phase transition boundary eventually reached the examined temperature, phase transition occurs under fixed external conditions. Such new insight obtained in this study opens up the new concept of time-programed stimuli-responsive polymer possessing a cleavage-induced phase transition.


Assuntos
Polímeros , Polímeros Responsivos a Estímulos , Ânions , Transição de Fase , Polímeros/química , Temperatura , Água/química
11.
Molecules ; 27(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36144844

RESUMO

The adeninate anion (Ade-) is a useful nucleophile used in the synthesis of many prodrugs (including those for HIV AIDS treatment). It exists as a contact ion-pair (CIP) with Na+ and K+ (M+) but the site of coordination is not obvious from spectroscopic data. Herein, a molecular-wide and electron density-based (MOWED) computational approach implemented in the implicit solvation model showed a strong preference for bidentate ion coordination at the N3 and N9 atoms. The N3N9-CIP has (i) the strongest inter-ionic interaction, by -30 kcal mol-1, with a significant (10-15%) covalent contribution, (ii) the most stabilized bonding framework for Ade-, and (iii) displays the largest ion-induced polarization of Ade-, rendering the N3 and N9 the most negative and, hence, most nucleophilic atoms. Alkylation of the adeninate anion at these two positions can therefore be readily explained when the metal coordinated complex is considered as the nucleophile. The addition of explicit DMSO solvent molecules did not change the trend in most nucleophilic N-atoms of Ade- for the in-plane M-Ade complexes in M-Ade-(DMSO)4 molecular systems. MOWED-based studies of the strength and nature of interactions between DMSO solvent molecules and counter ions and Ade- revealed an interesting and unexpected chemistry of intermolecular chemical bonding.


Assuntos
Pró-Fármacos , Sódio , Ânions , Dimetil Sulfóxido , Elétrons , Íons , Modelos Moleculares , Potássio , Solventes
12.
Anal Chem ; 94(38): 13269-13277, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36109852

RESUMO

An electrochemiluminescent (ECL)-photoacoustic (PA) dual-signal output biosensor based on the modular optimization and wireless nature of a bipolar electrode (BPE) was constructed. To further simplify the detection process, the BPE structure was designed as three separate units: anode ECL collection, cathode catalytic amplification, and intermediate functional sensing units. Specifically, the anode unit was placed with Eosin Yellow, a cheap and effective ECL reagent, and the cathode unit was a laser-induced polyoxometalate-graphene electrode, which was helpful to enhance the anode ECL signal. The intermediate functional sensing unit consisted of a temperature-sensitive conductive film. Further, using a carbon nano-onion nanocomposite with excellent absorption performance in the near-infrared region as a signal tag not only leads to changes in the electrical conductivity of the film through heat transfer and thus affects the ECL signal but also produces a strong PA response. With this design, PA and ECL signals can be output simultaneously. This work not only realizes multiple modularization processes in the design of sensors but also implements the diversification of signal output modes, which will enrich the joint research field of ECL detection technology and other new detection methods.


Assuntos
Técnicas Biossensoriais , Grafite , Neoplasias Ovarianas , Ânions , Técnicas Biossensoriais/métodos , Carbono , Técnicas Eletroquímicas/métodos , Eletrodos , Amarelo de Eosina-(YS) , Feminino , Grafite/química , Humanos , Medições Luminescentes/métodos , Cebolas , Neoplasias Ovarianas/diagnóstico , Polieletrólitos
13.
J Phys Chem Lett ; 13(38): 8921-8927, 2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36130195

RESUMO

Photolysis reaction pathways of [Au(III)Cl4]- in aqueous solution have been investigated by time-resolved X-ray absorption spectroscopy. Ultraviolet excitation directly breaks the Au-Cl bond in [Au(III)Cl4]- to form [Au(II)Cl3]- that becomes highly reactive within 79 ps. Disproportionation of [Au(II)Cl3]- generates [Au(I)Cl2]-, which is stable for ≤10 µs. In contrast, intense near-infrared lasers photolyze water to generate hydrated electrons, which then reduce [Au(III)Cl4]- to [Au(II)Cl3]- at 5 ns. Hydrated electrons further induce a chain reaction from [Au(II)Cl3]- to [Au(0)Cl]- by successively removing one Cl-. The zero-valency Au anions quickly polymerize and condense to form Au nanoparticles, which become the dominating product after 400 s. Our results reveal that the condensation of zero-valency Au starts with dimerization of gold clusters coordinated with chloride ions rather than direct condensation of pristine Au atoms.


Assuntos
Ouro , Nanopartículas Metálicas , Ânions , Cloretos , Ouro/química , Água/química , Espectroscopia por Absorção de Raios X , Raios X
14.
Environ Monit Assess ; 194(11): 837, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36169769

RESUMO

In the current survey, different hydrogeochemical processes governing the geochemistry of aquifers, the usefulness of groundwater for regular consumption, and agricultural purposes were evaluated around the Tummalapalle area. One hundred forty-four borehole locations were chosen to characterize the major physicochemical components of the aquifer water. The analysis results of pH inferred that the groundwater is nominally acidic to basic, and pH ranged from 6.6 to 8.4. The average concentrations of TDS, Ca2+, Mg2+, total hardness (TH), HCO3-, and total alkalinity (TA) are within the allowable limits of potable water quality as prescribed by the Bureau of Indian Standards (BIS) and WHO. However, the average concentrations of Na+, K+, Cl-, and SO42- were all below the permissible limit. All samples were analyzed with the help of Piper and Chadha charts to determine the dominant hydrogeochemical components of groundwater. The dominance of cations in groundwater in this region is in the sequence of Ca2+ > Na+ > Mg2+ > K+, followed by anions HCO3- > Cl- > SO42-. The Gibbs plot analysis suggested the predominance of rock aquifer interaction as the major hydrogeochemical process governing groundwater geochemistry in this region. The water quality index (WQI) of all groundwater samples in the Tummalapalle region was estimated, with 55% of the samples being potable grade. The different irrigation indices were analyzed for the groundwater samples to estimate their desirability for agriculture. The maximum number of water samples was found to be well-suited for cultivation.


Assuntos
Água Potável , Água Subterrânea , Poluentes Químicos da Água , Ânions/análise , Cátions/análise , Água Potável/análise , Monitoramento Ambiental/métodos , Água Subterrânea/química , Índia , Poluentes Químicos da Água/análise , Qualidade da Água
15.
Org Lett ; 24(37): 6722-6727, 2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36095147

RESUMO

The alkylations of chiral seven-membered rings fused to tetrazoles are highly diastereoselective. The diastereoselectivity depended on the placement and the size of the substituent on the ring and on the electrophile. Subsequent alkylations occurred with high stereoselectivity, allowing for the construction of quaternary stereocenters. Computational studies revealed that torsional effects are responsible for the observed diastereoselectivities. Substituted products can be reduced to the corresponding secondary amines, thus providing an approach for synthesizing diastereomerically enriched azepanes.


Assuntos
Aminas , Azepinas , Alquilação , Ânions , Estereoisomerismo , Tetrazóis
16.
Nature ; 609(7929): 1056-1062, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36071163

RESUMO

Folates are essential nutrients with important roles as cofactors in one-carbon transfer reactions, being heavily utilized in the synthesis of nucleic acids and the metabolism of amino acids during cell division1,2. Mammals lack de novo folate synthesis pathways and thus rely on folate uptake from the extracellular milieu3. The human reduced folate carrier (hRFC, also known as SLC19A1) is the major importer of folates into the cell1,3, as well as chemotherapeutic agents such as methotrexate4-6. As an anion exchanger, RFC couples the import of folates and antifolates to anion export across the cell membrane and it is a major determinant in methotrexate (antifolate) sensitivity, as genetic variants and its depletion result in drug resistance4-8. Despite its importance, the molecular basis of substrate specificity by hRFC remains unclear. Here we present cryo-electron microscopy structures of hRFC in the apo state and captured in complex with methotrexate. Combined with molecular dynamics simulations and functional experiments, our study uncovers key determinants of hRFC transport selectivity among folates and antifolate drugs while shedding light on important features of anion recognition by hRFC.


Assuntos
Antagonistas do Ácido Fólico , Ácidos Nucleicos , Aminoácidos/metabolismo , Animais , Ânions/metabolismo , Transporte Biológico , Carbono/metabolismo , Microscopia Crioeletrônica , Ácido Fólico/metabolismo , Antagonistas do Ácido Fólico/farmacologia , Humanos , Mamíferos/metabolismo , Metotrexato/farmacologia , Ácidos Nucleicos/metabolismo , Proteína Carregadora de Folato Reduzido/metabolismo
17.
Inorg Chem ; 61(38): 15108-15115, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36106989

RESUMO

Anion-responsive sign inversion of circularly polarized luminescence (CPL) was successfully achieved by N3O6-type nona-coordinated europium(III) (Eu3+) complexes [(R)-1 and (S)-1] composed of a less-hindered unsymmetrical N3-tridentate ligand (a chiral bis(oxazoline) ligand) and three O2-chelating (ß-diketonate) ligands. Here, (R)-1 exhibited a positive CPL signal (IL - IR > 0) at the 5D0 → 7F1 transition of Eu3+, which can be changed to a negative sign (i.e., IL - IR > 0 → IL - IR < 0) by the coordination of trifluoroacetic anions (CF3COO-) to the Eu3+ center. However, (R)-1 preserved the original positive CPL signal (i.e., IL - IR > 0 → IL - IR > 0) in the presence of a wide range of competing anions (Cl-, Br-, I-, BF4-, ClO4-, ReO4-, PF6-, OTf-, and SbF6-). Thus, (R)-1 acts as a smart target identifiable probe, where the CPL measurement (IL - IR) can distinguish the signals from the competing anions (i.e., IL - IR < 0 vs IL - IR > 0) and eliminate the background emission (i.e., IL - IR = 0) from the background emitter (achiral luminescent compounds). The presented approach is also promising in terms of bio-inspired optical methodology because it enables nature's developed chiral sensitivity to use circularly polarized light for object identification (i.e., IL - IR = 0 vs | IL - IR | > 0).


Assuntos
Európio , Luminescência , Ânions , Ligantes , Medições Luminescentes/métodos
18.
J Phys Chem B ; 126(38): 7271-7285, 2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36112533

RESUMO

Room temperature molecular dynamics (MD) simulations of the globular protein α-lactalbumin in aqueous solutions containing BMIM (1-butyl-3-methylimidazolium) based ionic liquids (ILs) with a series of Hofmeister anions have been carried out. In particular, effects of anions of different shapes/sizes and hydrophobic/hydrophilic characters, namely, thiocyanate (SCN-), dicyanamide (DCA-), methyl sulfate (MS-), triflate (TFO-), and bis(trifluoromethane) sulfonimide (TF2N-) on the heterogeneous dynamic environment at the interface around the protein have been explored. The calculations revealed exchange of population between water and IL cation-anion components beyond the first layer of bound water molecules at the protein surface. Further, increasingly restricted diffusivity of the IL components and water around the protein has been found to be associated with a longer time scale for the onset of dynamic heterogeneity at the interface. Restricted diffusivity of water molecules at the interface in the presence of the ILs has been found to be correlated with the longer time scale of structural relaxations of protein-water hydrogen bonds at the interface. More importantly, the time scale associated with the reorientations of the anions has been found to be anticorrelated with their translational diffusivity, with the effect being more at the interface as compared to the bulk IL solutions. It is demonstrated that the nonuniform ability of the anions to form hydrogen bonds with water due to their differential shapes and hydrophilic characters is the origin of such anticorrelation.


Assuntos
Líquidos Iônicos , Ânions/química , Cátions , Líquidos Iônicos/química , Lactalbumina , Tiocianatos , Água/química
19.
Nano Lett ; 22(18): 7535-7544, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36070490

RESUMO

The rechargeability of aqueous zinc metal batteries is plagued by parasitic reactions of the zinc metal anode and detrimental morphologies such as dendritic or dead zinc. To improve the zinc metal reversibility, hereby we report a new solution structure of aqueous electrolyte with hydroxyl-ion scavengers and hydrophobicity localized in solvent clusters. We show that although hydrophobicity sounds counterintuitive for an aqueous system, hydrophilic pockets may be encapsulated inside a hydrophobic outer layer, and a hydrophobic anode-electrolyte interface can be generated through the addition of a cation-philic, strongly anion-phobic, and OH--reactive diluent. The localized hydrophobicity enables less active water and less absorbed water on the Zn anode surface, which suppresses the parasitic water reduction; while the hydroxyl-ion-scavenging functionality further minimizes undesired passivation layer formation, thus leading to superior reversibility (an average Zn plating/stripping efficiency of 99.72% for 1000 cycles) and lifetime (80.6% capacity retention after 5000 cycles) of zinc batteries.


Assuntos
Eletrólitos , Zinco , Ânions , Cátions , Interações Hidrofóbicas e Hidrofílicas , Solventes , Água
20.
J Phys Chem B ; 126(36): 6979-6984, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-36047943

RESUMO

Although anionic N and O sites have been widely used in chemisorption of CO2, carbanions are much less explored for CO2 capture. Here we employ ab initio calculations and quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations to examine the interaction between CO2 and the malononitrile carbanion, [CH(CN)2]-. We have explored the potential energy surface of CO2 binding by scanning the C-C distance between CO2 and the central C site of the carbanion. We find that CO2 prefers to bind to the nitrile group physically rather than to form a C-C bond via the carboxylation reaction at the sp2 C site. Moreover, the two -CN groups can attract two CO2 molecules at equal strength. The presence of an alkali metal ion enhances both physical and chemical interactions of CO2 with the malononitrile carbanion. QM/MM MD simulations further confirm the preference of physical interaction in the condensed ionic liquid phase with a phosphonium cation. Our findings suggest that ionic liquids based on the malononitrile carbanion may have a high CO2 solubility for carbon capture.


Assuntos
Dióxido de Carbono , Líquidos Iônicos , Ânions/química , Dióxido de Carbono/química , Líquidos Iônicos/química , Nitrilas
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