Alkali Metal Ions Research Articles

Influence of modified perylene-3, 4, 9, 10-tetracarboxylate with alkali metals ions as surfactant on the yield of hydrothermal liquid-phase exfoliated graphene sheets

Influence of modified perylene-3, 4, 9, 10-tetracarboxylate with alkali metals ions as surfactant on the yield of hydrothermal liquid-phase exfoliated graphene sheets

Third-order nonlinear optical responses of bis(15-crown-5)-stilbenes binding to one- or two-alkali metal cation (Li+, Na+ and K+)

Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications, such as cation detectors, because of their ability to selectively bind to alkali metal cations, Bis(15-crown-5)-stilbenes and its derivatives with complexation of one- or two-alkali metal cation (Li+, Na+ and K+) have been theoretically investigated by quantum chemistry methods. The coordination of alkali cations results in partial shrinkage of crown ethers, which directly affected natural distribution analysis charges and molecular orbital energy levels. The number of alkali metal ions has significant effects on absorption spectra and mean second hyperpolarizability. When one alkali metal ion was added to the anticonformer of bis(15-crown-5)-stilbene, the absorption spectra were obviously redshifted and the mean second hyperpolarizability values were slightly increased; while two alkali metal ions were added to bis(15-crown-5)-stilbene, the absorption spectra were obviously blue shifted and the mean second hyperpolarizability values decreased. On the other hand, as the radius of the alkali ions increased, the mean second hyperpolarizability values of the compounds increased gradually. It is indicated that the mean second hyperpolarizability value is sensitive to the number and radius of the alkali metal cations, thus the third order nonlinear optical response can be used as a signal to detect the number and type of alkali metal ions.

Organic small-molecule fluorescent probe-based detection for alkali and alkaline earth metal ions in biological systems.

Metal ions widely exist in biological systems and participate in many vital biochemical processes. Monitoring and analyzing metal ions in biological systems can help reveal physiological processes and understand disease causes. There are various detection methods for metal ions, among which organic small-molecule fluorescent probes have significant advantages, such as high fluorescence quantum yield, easy modification, good biocompatibility, high sensitivity, and fast real-time detection. This review presents recent studies on fluorescent probes for alkali and alkaline earth metal ions (including Na+, K+, Ca2+, and Mg2+) in biological systems. All the candidates are organized according to their structures, and the sensing mechanisms of fluorescent probes are also highly taken into account. Finally, the challenges, trends and prospects of fluorescent probes in metal ion detection are discussed. We hope that this review can provide guidance for the development of fluorescent molecular probe-based alkali and alkaline earth metal ion detection methods in the future.

SiC3N3 monolayer as a universal anode for alkali metal-ion batteries.

Our density functional theory calculations show that silicon doping in g-CN (SiC3N3) can improve the electrochemical performance of g-CN as an anode of alkali metal-ion batteries and solve the problems of too high adsorption ability and migration energy barrier commonly found in porous carbon nitride. The stability of SiC3N3 was verified by molecular dynamics simulations and phonon spectroscopy. Elastic constant calculations revealed that the Si doping in g-CN can improve its mechanical properties. Specifically, Li/Na/K has a suitable adsorption capability (-0.71/-0.52/-0.98 eV) and a lower migration barrier (0.73/0.43/0.21 eV) on SiC3N3, where the barrier of a single Li-ion is the lowest among the doped porous carbon nitride materials studied so far. Moreover, SiC3N3 exhibits a high theoretical capacity (253/1512/1512 mA h g-1) and a low open-circuit voltage (0.48/0.18/0.31 V) for Li/Na/K ion batteries. Compared with B-doped g-CN previously studied, Si doping can more effectively improve the electronic conductivity of g-CN owing to greater charge transfer between Si and g-CN; the migration energy barrier of alkali metal ions on SiC3N3 is reduced more significantly due to its puckered structure instead of a planar structure; and the capacity of SiC3N3 is nearly doubled for alkali metal ion batteries because it has more feasible adsorption sites for alkali metals. These results suggest that Si-doped g-CN can be a universal anode material for alkali metal ion batteries.

Enhanced near-infrared light-induced photoresponse via transition of monocrystalline phase and surface reconstruction

Rare-earth-doped upconversion (UC) materials are ideal candidates for solar photovoltaic conversion and NIR response devices due to their unique spectral conversion properties. However, their low efficiency remains a tremendous challenge for practical applications. Here, we constructed an efficient NIR light-responsive device by coating a Si-photoresistor with a transparent gel consisting of UC powders and an organic polymer matrix. We show that reasonable introduction of alkali metal ions (Na+, K+, and Cs+) into the lattice of UC crystals results in the improvement of photoelectricity conversion efficiency, due to the high crystallinity and surface reconstruction caused by alkali metal ion doping.

Filling carbon: a microstructure-engineered hard carbon for efficient alkali metal ion storage

Carbonaceous materials are the most promising anodes for alkali metal-ion batteries (AMIBs); however, it is still a great challenge to construct carbonaceous materials with elaborate microstructures to achieve superior electrochemical performance.

A redox-active inorganic crown ether based on a polyoxometalate capsule.

Cation-uptake has been long researched as an important topic in materials science. Herein we focus on a molecular crystal composed of a charge-neutral polyoxometalate (POM) capsule [MoVI72FeIII30O252(H2O)102(CH3CO2)15]3+ encapsulating a Keggin-type phosphododecamolybdate anion [α-PMoVI12O40]3-. Cation-coupled electron-transfer reaction occurs by treating the molecular crystal in an aqueous solution containing CsCl and ascorbic acid as a reducing reagent. Specifically, multiple Cs+ ions and electrons are captured in crown-ether-like pores {MoVI3FeIII3O6}, which exist on the surface of the POM capsule, and Mo atoms, respectively. The locations of Cs+ ions and electrons are revealed by single-crystal X-ray diffraction and density functional theory studies. Highly selective Cs+ ion uptake is observed from an aqueous solution containing various alkali metal ions. Cs+ ions can be released from the crown-ether-like pores by the addition of aqueous chlorine as an oxidizing reagent. These results show that the POM capsule functions as an unprecedented "redox-active inorganic crown ether", clearly distinguished from the non-redox-active organic counterpart.

Mammea A/AA (MA) potency as ratiometric absorbance based molecular probe: Cations detection and quantification ability

MA is a phenyl coumarin extracted from the bark of the stem of Mammea Africana. This compound exhibits two absorption peaks in the region between 300 and 550 nm, whose relative wavelength positions, their absolute absorbances and the ratio of their absorbances depend on the molecular environment. In this work, this property was exploited for the first time to detect and quantify metal ions in aqueous solution. Alkali (Mg2+, Na+, Ca2+, K+), transition (Zn2+, Fe2+, Co2+, Cu2+) and heavy (Hg2+, Pb2+, Sn2+) metal ions were considered. We found that the MA spectroscopic response depends on the nature and class of the cations in solution, indicating a binding interaction. Our method applied to the detection and quantification of cations in different mineral waters, allowed us to obtain the concentrations of different cations with good accuracy. A theoretical calculation using DFT methods provided the geometrical structures of the organometallic complexes, which revealed that the metal ions are chelated by MA at the carbonyl site of the coumarin moiety. In addition, calculation of electronic transitions by TDDFT as well as analysis of MOs showed that the photophysics of complexes involving MA and a metal cation is governed by intra-ligand, ligand-to-metal and metal-to-ligand electron transfer.

Main group elements in electrochemical hydrogen evolution and carbon dioxide reduction.

Main-group elements are renowned for their versatile reactivities in organometallic chemistry, including CO2 insertion and H2 activation. However, electrocatalysts comprising a main-group element active site have not yet been widely developed for activating CO2 or producing H2. Recently, research has focused on main-group element-based electrocatalysts that are active in redox systems related to fuel-forming reactions. These studies have determined that the catalytic performances of heavier main-group element-based electrocatalysts are often similar to those of transition-metal-based electrocatalysts. Our group has recently reported the scope of including the main-group elements in the design of molecular catalysts and explored their applications in redox catalysis, such as the generation of H2 upon coupling of two protons (H+) and two electrons (e-). This feature article summarizes our research efforts in developing molecular electrocatalysts comprising main-group elements at their active sites. Furthermore, we highlight their influence on the rate-determining step, thereby enhancing the reaction rate and product selectivity for multi-H+/multi-e- transfer catalysis. Particularly, we focus on the performance of our recently reported molecular Sn- or Sb-centered macrocycles for electrocatalytic H2 evolution reaction (HER) and on how their mechanisms resemble those of transition-metal-based electrocatalysts. Moreover, we discuss the CO2 reduction reaction (CO2RR), another promising fuel-forming reaction, and emphasize the recent progress in including the main-group elements in the CO2RR. Although the main-group elements are found at the active sites of the molecular catalysts and are embedded in the electrode materials for studying the HER, molecular catalysts bearing main-group elements are not commonly used for CO2RR. However, the main-group elements assist the CO2RR by acting as co-catalysts. For example, alkali and alkaline earth metal ions (e.g., Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, and Ba2+) are known for their Lewis acidities, which influence the thermodynamic landscape of the CO2RR and product selectivity. In contrast, the elements in groups 13, 14, and 15 are primarily used as dopants in the preparation of catalytic materials. Overall, this article identifies main-group element-based molecular electrocatalysts and materials for HER and CO2RR.

Selective heterogeneous capture and release of actinides using carborane-functionalized electrodes.

We report the heterogenization of molecular, electrochemically switchable ortho-substituted carboranes (POCb, POCb-Pyr) for selective metal capture. Films of POCb and POCb-Pyr on glassy carbon and carbon fiber (CF) electrodes demonstrated heterogeneous electrochemical behaviour that was enhanced by the inclusion of single-walled carbon nanotubes (CNTs). Galvanostatically charged CF|CNT|POCb and CF|CNT|POCb-Pyr electrodes selectively captured and released actinides (Th4+, UO22+) from mixed solutions containing alkali (Cs+), lanthanide (Nd3+, Sm3+) and actinide (Th4+, UO22+) metal ions.

Ni2P immobilized on N,P-codoped porous carbon sheets for alkali metal ion batteries and storage mechanism

An integrated composite architecture composed of N/P codoped porous carbon sheets and embedded Ni2P NPs (Ni2P⊂N/P-CNS) was synthesized by a self-template strategy and demonstrated superior electrochemical performance as alkali ion battery anode.

TheKspgap enabled precipitation transformation reactions from transition metal hydroxides to sulfides for alkali metal ion storage

A rule that theKspvalues for the sulfides are significantly lower than those for the corresponding hydroxides for the elements in groups 9–12 is reported, along with the precipitation transformation reactions and the battery applications.

From BPS4 to AB3P2S10 (A = Na, K): cations inducing dimension reduction and bandgap enlargement.

Regulating the crystal structure by cations is one of the most effective methods to adjust the performances of optical materials and enrich the structural chemistry of solid-state inorganic crystals. In this work, only boron-thiophosphate BPS4 (BPS) was used as the template. By introducing alkali metal ions, Na+ and K+, the synthesis, structural revolution, and bandgap adjustment were studied. Namely, the first quaternary boron-thiophosphates, AB3P2S10 (A = Na, K) (ABPS) were obtained, whose anion skeleton decreased to zero dimension from one dimension (1D) in BPS. In addition, the bandgap showed obvious improvement from 3.30 (BPS) to 3.42 and 3.49 eV (ABPS). Structural studies and theoretical analyses indicated that the insert of cations separates the infinite chains to [B3P2S10] clusters, localizes the electrons around the S2- in [BS4] and [PS4] groups, and widens the bandgaps. This work could enrich the structural chemistry of boron-thiophosphates and reveal that ionic bonds can modulate the covalent skeleton and show the effect on the optical properties.

On the mechanism of acceptorless dehydrogenation of N-heterocycles catalyzed by tBuOK: a computational study.

The catalytic acceptorless dehydrogenation (ADH) of saturated N-heterocycles has recently gained considerable attention as a promising strategy for hydrogen release from liquid organic hydrogen carriers (LOHCs). Recently, a simple tBuOK base-promoted ADH of N-heterocycles was developed by Yu et al. (Adv. Synth. Catal. 2019, 361, 3958). However, it is still open as to how the tBuOK plays a catalytic role in the ADH process. Herein, our density functional study reveals that the tBuOK catalyzes the ADH of 1,2,3,4-tetrahydroquinoline (THQ) through a quasi-metal-ligand bifunctional catalytic channel or a base-catalyzed pathway with close energy barriers. The hydride transfer in the first dehydrogenation process is determined to be the rate determining step, and the second dehydrogenation can proceed directly from 34DHQ regulated by the tBuOK. In addition, the computational results show that the cooperation of a suitable alkali metal ion with the tBuO- group is so critical that the tBuOLi and the isolated tBuO- are both inferior to tBuOK as a dehydrogenation catalyst.

Influence of alkali metal cations on the formation of the heterobimetallic actinide tert-butoxides [AnM3(OtBu)7] and [AnM2(OtBu)6] (AnIV = Th, U; MI = Li, Na, K, Rb, Cs).

Heterobimetallic tert-butoxides of alkali metal cations with tetravalent actinide centers exhibit two distinctive structural motifs, [AnM2(OtBu)6] and [AnM3(OtBu)7] (AnIV = Th, U and MI = Li, Na, K, Rb, Cs), evidently governed by the size of the alkali metal ions. Both [AnM3(OtBu)7] AnM3 (AnIV = U, MI = Li; AnIV = Th, MI = Li, Na) and [AnM2(OtBu)6] AnM2 (AnIV = U, MI = Na-Cs; AnIV = Th, MI = K-Cs) compounds are obtained in nearly quantitative yields by reacting actinide and alkali metal silyl amides with an excess of tert-butyl alcohol. The AnM3 complexes form a cubane-type coordination motif, whereas the AnM2 complexes display a geometry resembling two face-shared bipyramids. The sodium derivatives of thorium and uranium (ThNa3 and UNa2) allow the determination of the structural transition threshold as a function of the ratio of the ionic radii ri(AnIV)/ri(MI). The AnM3 complexes are formed for ratios above 0.92 and the AnM2 type is formed for ratios below 0.87. All compounds are unambiguously characterized in both solution and solid states by NMR and IR spectroscopic studies and single crystal X-ray diffraction analyses, respectively.

Effect of intermolecular interaction of the charge-transfer complex between molecular "tweezers" and C60/C70 on second-order nonlinear optical properties.

To enhance understanding of the correlation between the intermolecular interaction and second-order nonlinear optical (NLO) properties, we studied a "molecular tweezer" with two corannulene substituents linked by a tetrahydro[5]helicene imide, which enabled highly sensitive and selective complexation of C60/C70 through convex-concave π-π interactions. The geometric structure, molecular orbitals, intermolecular interactions, electron absorption spectra and second-order NLO properties of the charge-transfer (CT) complexes formed by molecular tweezers and C60/C70 were studied by density functional theory. Larger fullerenes helped to increase the intermolecular interaction and CT, thereby increasing the first hyperpolarizabilities of CT complexes. Embedding of lithium ions helped to enhance the electron-absorption ability of fullerenes, thereby increasing the intermolecular interaction and intermolecular CT and, thus, enhancing their first hyperpolarizability significantly. Our data indicated that, through structure adjustment (including increasing the volume of fullerene and embedding alkali metal ions), we could enhance intermolecular interactions and improve intermolecular CT significantly. These actions could improve the second-order NLO properties of CT complexes.

Synergistic theoretical and experimental study on the ion dynamics of bis(trifluoromethanesulfonyl)imide-based alkali metal salts for solid polymer electrolytes.

Model validation of a well-known class of solid polymer electrolyte (SPE) is utilized to predict the ionic structure and ion dynamics of alternative alkali metal ions, leading to advancements in Na-, K-, and Cs-based SPEs for solid-state alkali metal batteries. A comprehensive study based on molecular dynamics (MD) is conducted to simulate ion coordination and the ion transport properties of poly(ethylene oxide) (PEO) with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt across various LiTFSI concentrations. Through validation of the MD simulation results with experimental techniques, we gain a deeper understanding of the ionic structure and dynamics in the PEO/LiTFSI system. This computational approach is then extended to predict ion coordination and transport properties of alternative alkali metal ions. The ionic structure in PEO/LiTFSI is significantly influenced by the LiTFSI concentration, resulting in different lithium-ion transport mechanisms for highly concentrated or diluted systems. Substituting lithium with sodium, potassium, and cesium reveals a weaker cation-PEO coordination for the larger cesium-ion. However, sodium-ion based SPEs exhibit the highest cation transport number, indicating the crucial interplay between salt dissociation and cation-PEO coordination for achieving optimal performance in alkali metal SPEs.

Review on the promising roles of alkali metals toward highly efficient perovskite light-emitting diodes

Alkali metals have been used to obtain high-performance perovskite light-emitting diodes. In this review, we present an overview of the advances in alkali metal ions applied in PeLEDs. Challenges and the outlook are presented for their future applications.

Aluminum functionalized few-layer silicene as anode material for alkali metal ion batteries

We have investigated the possibility of using aluminum functionalized silicene trilayers (ABC-Si4Al2) as an anode material for alkali metal ion batteries (AMIBs).

1, 10-phenanthroline derivative as colorimetric and ratiometric fluorescence probe for Zn2+ and Cd2+

A colorimetric and ratiometric fluorescent probe 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline (probe 1), was designed and synthesized for sensitive and selective detection of Zn2+ and Cd2+ ions in methanol, test paper and actual water samples. When probe 1 was excited at 350 nm in methanol solution, in the presence of alkali metal ions, alkali-earth metal ions and a variety of transition metal ions, it showed sensitive fluorescence selectivity to Zn2+ and Cd2+ ions. With the addition of Zn2+, the color of the solution changed from purple to cyan with the naked eye, and with the addition of Cd2+, the color of the solution changed from purple to blue. The fluorescence intensity of probe 1 showed a good linear relationship with Zn2+ and Cd2+ concentrations, and the detection limits were 0.04 μM and 0.11 μM, respectively. The binding mode of probe 1 and Cd2+ was discussed according to the 1-Cd single X-ray crystal structure. In addition, the results of strip test and real water sample test showed that probe 1 has potential application in environmental metal ion recognition and detection.