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A donor-acceptor Schiff-base fluorescent probe BKS with chelation enhanced fluorescence (CHEF) mechanism was designed and synthesized via benzophenone(Acceptor), salicylaldehyde and carbazole(Donor) for Al3+ detection, which exhibited typical aggregation-induced emission (AIE) characteristic. BKS probe could provide outstanding selectivity to Al3+ with a prominent fluorescence "turn-on" at 545 nm in a wide pH range from 2 to 11. By the Job's plot, the binding stoichiometry ratio of probe BKS to Al3+ was determined 1:1. The proposed strategy offered a very low limit of detection at 1.486 µM in THF/H2O(V/V = 1:4, HEPBS = 10 mM, pH = 7.40), which was significantly lower than the standard of WHO (Huang et al., Microchem J 151:104195, 2019)-(Yongjie Ding et al., Spectrochim Acta Mol Biomol Spectrosc 167:59-65, 2021) guidelines for drinking water. BKS probe could provide a wider linear detection range of 50 to 500 µM. Furthermore, the probe could hardly be interfered by other examined metal ions. The analysis of Al3+ in real water samples with appropriate recovery (100.72 to 102.85) with a relative standard deviation less than 2.82% indicated the accuracy and precision of BKS probe and the great potential in the environmental monitoring of Al3+.

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δ-MnO2 is a promising cathode material for aqueous aluminium-ion batteries (AAIBs) for its layered crystalline structure with large interlayer spacing. However, the excellent Al ion storage performance of δ-MnO2 cathode remains elusive due to the frustrating structural collapse during the intercalation of high ionic potential Al ion species. Here, it is discovered that introducing heterogeneous metal dopants with high bond dissociation energy when bonded to oxygen can significantly reinforce the structural stability of δ-MnO2 frameworks. This reinforcement translates to stable cycling properties and high specific capacity in AAIBs. Vanadium-doped δ-MnO2 (V-δ-MnO2) can deliver a high specific capacity of 518 mAh g-1 at 200 mA g-1 with remarkable cycling stability for 400 cycles and improved rate capabilities (468, 339, and 285 mAh g-1 at 0.5, 1, and 2 A g-1, respectively), outperforming other doped δ-MnO2 materials and the reported AAIB cathodes. Theoretical and experimental studies indicate that V doping can substantially improve the cohesive energy of δ-MnO2 lattices, enhance their interaction with Al ion species, and increase electrical conductivity, collectively contributing to high ion storage performance. These findings provide inspiration for the development of high-performance cathodes for battery applications.

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Covalent organic frameworks (COFs) have received increased interest in recent years as an advanced class of materials. By virtue of the available monomers, multiple conformations and various linkages, COFs offer a wide range of opportunities for complex structural design and specific functional development of materials, which has facilitated the widespread application in many fields, including multi-valent metal ion batteries (MVMIBs), described as the attractive candidate replacing lithium-ion batteries (LIBs). With their robust skeletons, diverse pores, flexible structures and abundant functional groups, COFs are expected to help realize a high performance MVMIBs. In this review, we present an overview of COFs, describe advances in topology design and synthetic reactions, and study the application of COFs in MVMIBs, as well as discuss challenges and solutions in the preparation of COFs electrodes, in the hope of providing constructive insights into the future direction of COFs.

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An efficient fluorescent cation chemosensor based on fluorescein L4 was well prepared and identified with spectroscopy analyses. UV-vis and fluorescence measurements examined the analyte complexation of the L4 with various cations, demonstrating a clear tendency to Al3+ ion. In the Job plot study, a stoichiometry ratio of a complex between L4 and Al3+ ion was determined to be 1: 2 (L4: Al3+). A stoichiometry ratio of complex between L4 and Al3+ ion was determined to be 1: 2 (L4: Al3+) using the Job plot. The association constant (Ka) of the L4-Al3+ complex was found 2.8 × 107 M-2. The obtained limit of detection (LOD) value (1.37 × 10-6 M for Al3+) exhibited the considerable sensitivity of the chemosensor L4 to Al3+ ion. DFT/TD-DFT calculations have also been employed to support the binding mode and photophysical properties of the complexation of chemosensor L4 to Al3+ ion and also to investigate the enhancement of L4 fluorescence by Al3+ ion.

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The present study developed a green metallochromic sensor that detects aluminium (Al(III)) ions in solution and solid state using anthocyanin extract from purple onion peels embedded in bacterial cellulose nanofibers (BCNFs). The CIE Lab colour parameters demonstrated that Al(III) binding causes a sensible change in colour. A variety of metal ions including K+, Mn2+, Cu2+, Hg2+, Cr2+, Pb2+ and Ni2+ were used to challenge the sensor to determine its selectivity. The findings demonstrated that the suggested sensor showed excellent selectivity toward Al(III) ion. Al(III) is quantitatively detected by the sensing method with detection limits in the range between 30-200 and 20-300 ppm in solution and solid state, respectively, and through observation with naked eye. The fabricated green metallochromic sensor is promising to be a simple, cheap, mobile and easily operable for real-time and on-site detection of Al(III) ions in food matrices.

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We constructed a novel-binding site for metal ion detection using a fused tetrazole ring conjugated with aminopyrene (R). The designed structure of the molecule was successfully synthesized and determined the probe's selectivity by testing various metal ions and found that the probe effectively detects Al3+ ion visually. Checked the sensing ability of the probe with different approaches (fluorimetric and colorimetric), and the effectiveness is double confirmed. The added Al3+ ion to R procured a rapid change in color from yellowish orange to colorless. Under the UV lamp, a turn-on blue fluorescence was observed after adding aluminium ion, whereas the probe was non-fluorescent before detecting aluminium ion. The probable interface of the probe with aluminium ion has also been expected from HRMS spectral analysis results. The probe's utility in real-time monitoring of Al3+ ion in water is confirmed by a simple test kit prepared using filter paper. The kit showed a possible naked-eye detection with a notable color change, and when checked, the aluminium ion detected test kit under a UV lamp showed blue fluorescence.

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Carbon xerogels were synthesized using a soft-template route with resorcinol as the carbon source and sodium carbonate as the catalyst. The influence of the resorcinol to catalyst ratio in the range of 500-20,000 on pore structure, graphitic domains, and electronic conductivity of as-prepared carbon xerogels, as well as their performance in an aluminium ion battery (AIB), was investigated. After carbonization steps of the polymers up to 800 °C, all carbon samples exhibited similar specific volumes of micropores (0.7-0.8 cm³ g-1), while samples obtained from mixtures with R/C ratios lower than 2000 led to carbon xerogels with significantly higher mesopore diameters up to 6 nm. The best results, in terms of specific surface (1000 m² g-1), average pore size (6 nm) and reversible capacity in AIB cell (28 mAh g-1 @ 0.1 A g-1), were obtained with a carbon xerogel sample synthetized at a resorcinol to catalyst ratio of R/C = 500 (CXG500). Though cyclic voltammograms of carbon xerogel samples did not exhibit any sharp peaks in the applied potential window, the presence of both oxidation and a quite wide reduction peak in CXG500-2000 cyclic voltammograms indicated pseudocapacitance behaviour induced by diffusion-controlled intercalation/de-intercalation of AlCl4- ions into/from the carbon xerogel matrix. This was confirmed by shifting of the (002) peak towards lower 2θ angle values in the XRD pattern of the CXG500 electrode after the charging step in AIB, whereas the contribution of pseudocapacitance, calculated from half-cell measurements, was limited to only 6% of overall capacitance.

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A simple photochromic Schiff base was successfully prepared by the condensation of salicylaldehyde and benzoyl hydrazine. This compound has reversible photochromic properties based on isomerization and ESIPT mechanisms. In organic solvents, after irradiation with 365 nm UV light for 2 min, the absorption peak at 367 nm of the compound showed a significant decrease, while a double absorption peak appeared at 418 nm and 438 nm, accompanied by a significant change of the solution color from colorless to yellow. The compound can also complex with Al3+ at the molar ratio of 2:1 in the water solution (acetonitrile/water, v/v, 1:99), resulting in significantly enhanced fluorescence of the compound, so as to achieve fluorescence detection of Al3+ in living cells and water samples.

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As an unnecessary trace element, the content of aluminium in biological systems should be strictly controlled. Therefore, it was necessary to develop a convenient method for detection of aluminium ions. In this study, a fluorescent probe based on polythiophene derivatives was developed and used to detect Al3+ in Chinese traditional pasta. The fluorescence of this probe showed a significant decrease in hexamethylenetetramine-HCl buffer solution (pH 5) when Al3+ was present. In addition, the probe exhibited good sensitivity and selectivity to Al3+ over other metal ions when EDTA was used as the masking agent. Fluorescence intensity had a good linear relationship with the Al3+ concentration in the range 0.1-10 µM and the limit of detection for Al3+ was 39 nM. Furthermore, the probe was successfully applied to detect Al3+ in food samples and the results were consistent with ICP-AES.

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Developing high performance fluorescent chemosensor for Al3+ detection is highly desirable, due to the excess of Al3+ will lead to many diseases. In this paper, a simple 2-hydroxynaphthalene-based fluorescent chemosensor has been synthesized and characterized by different spectroscopic methods. The compound exhibited an "turn-on-type" fluorescent chemosensing for the detection of Al3+, which was ascribed to the chelation-enhanced fluorescence (CHEF). The high selectivity and sensitivity of the compound for Al3+ were verified by fluorescence spectra in its DMF solution, and the enhancement of fluorescent intensity could be observed by naked-eye from non-fluorescence to green light. The detection limit of the compound for Al3+ was found to be 4.22 × 10-8 M and the stability constant was 4.82 × 104 M-1. The 1:1 binding stoichiometry of the compound to Al3+ was confirmed from the Job's plot based on fluorescence titrations. Additionally, the sensing process of the compound to Al3+ was chemically reversible by adding Na2EDTA. Importantly, the probe was successfully applied to quantitative analysis of Al3+ in real drug and potable water samples.

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The foreseen high penetration of fluctuant renewable energy sources, such as wind and solar, will cause an increased need for batteries to store the energy produced and not instantaneously consumed. Due to the high production cost and significant environmental impacts associated with the production of lithium-ion nickel-manganese-cobalt (Li-ion NMC) batteries, several chemistries are proposed as a potential substitute. This study aims to identify and compare the lifecycle environmental impacts springing from a novel Al-ion battery, with the current state-of-the-art chemistry, i.e., Li-ion NMC. The global warming potential (GWP) indicator was selected to express the results due to its relevance to society, policy and to facilitate the comparison of our results with other research. The cradle-to-grave process-based assessment uses two functional units: (1) per-cell manufactured and (2) per-Wh of storage capacity. The results identified the battery's production as the highest carbon intensity phase, being the energy usage the main contributor to GWP. In general, the materials and process involved in the manufacturing and recycling of the novel battery achieve a lower environmental impact in comparison to the Li-ion technology. However, due to the Al-ion's low energy density, a higher amount of materials are needed to deliver equivalent performance than a Li-ion.

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We have created a set of crystalline model structures exhibiting straight lines of Al3+ connected to chalcogenides (O2- , S2- , and Se2- ) connected to metal cations of varying valence (Sr2+ , Y3+ , Zr4+ , Nb5+ , and Mo6+ ). They were relaxed with density functional theory computations and analysed by Bader partitioning. As Al3+ ions are supposed to strongly interact with their atomic environment, we studied the electron density topology induced by higher-valent cations in the extended chemical neighbourhood of Al. In fact, we found a general decrease of ionic charges and an increasing displacement of the chalcogenides towards higher-valent ions for the heavier chalcogens. Therefore, we comprehensively screened S- and Se-containing compounds for candidates theoretically exhibiting low migration barriers for Al3+ ions by using Voronoi-Dirichlet partitioning and bond valence site energy calculations. The basis for this search is the Inorganic Crystal Structure Database. Indeed, we could extract six promising candidates with low Al3+ migration barriers. which are even lower than the barriers for any other element inside of these materials. This will encourage efforts towards preparing suitable Al3+ conductors.

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Capping agents are the essential factor in nanoscience and nanotechnology. However, the types of capping agents are greatly limited. Defying conventional beliefs, here is shown that metal cations can also be considered as capping agents for oxide nanoparticles, particularly in maintaining their colloidal stability and controlling their facets. Here the general stabilizing effects of multivalent cations for oxide nanoparticles, and the facet controlling role of Al3+ ions in the growth and ripening of Cu2 O octahedra, are demonstrated. This discovery broadens the view of capping agent and opens doors for nanosynthesis, surface treatment, and beyond.

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Yerba mate tea contains various biochemically active substances. However, it can contain toxic metals. Thus, this work reports the total concentrations of Cd, Cu, Pb and Al in the commercial products, as well as the concentrations in infusions prepared. The bioaccessibility of these metals in these infusions was determined for the first time by in vitro digestion. For Al, its bioaccessibility was estimated in the presence of other ingredients used in tea consumption. In addition, the concentrations of phenolic compounds in infusions were also determined. All metals studied were detected in the samples ranging from 76 ng g-1 (Cd) to 526 µg g-1 (Al). In general, Cd and Cu were the most bioaccessible metals, while Al was found in a relatively inert form. The addition of sugar and honey in infusions decreased the Al bioaccessibility. The relationship between the phenolic and the leaching of Al for the beverages was observed.

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A highly selective method has been developed for the fluorometric determination of chlortetracycline (CTC) among other tetracycline antibiotics (TCs). It is making use of fluorescent Au/Pt nanoclusters (NCs) capped with polyethyleneimine (Au/PtNCs@PEI). The nanoprobe, with a green emission peaking at 512 nm, was synthesized by an environmentally friendly hydrothermal method. The capped NCs have a large Stokes shift (∼150 nm), are insensitive to extreme pH values and high ionic strength, and are excellently photostable under UV irradiation. In the presence of CTC, the fluorescence of the capped NCs is quenched due to aggregation. The effect is also found for tetracycline, oxytetracycline and doxycycline. This shows that sensitive but non-selective detection of such TCs is possible. However, CTC is specifically complexed by Al(III) ions, and this generates a strong fluorescence peaking at 520 nm even though the fluorescence of the capped NCs is fully quenched. Obviously, the effects are caused by CTC only, and this enables CTC to be specifically recognized by an "on-off-on" strategy. Fluorescence increases linearly in the 0.5 to 10 µM CTC concentration range, and the limit of detection is 0.35 µM. The method was successfully applied to the determination of CTC in (spiked) milk, and the recoveries suggest that this fluorescent probe is an effective tool for detecting CTC in foodstuff. Graphical abstract Schematic illustration and photographic images of the luminescence quenching response of Au/Pt nanoclusters (Au/PtNCs) toward chlortetracycline (CTC) (from on to off), and then the recovery upon Al3+ addition (from off to on).

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A simple and highly selective aluminium ion fluorescent probe (N-n-butyl-4-[3,3'-((2-aminoethyl)azanediyl)bis(N'-(2-hydroxy-3-methoxybenzylidene)-propanehydrazide)]-1,8-naphthalimide) (P-1) employing 1,8-naphthalimide as the fluorophore group and Schiff base as the recognition group has been successfully synthesized and systemically characterized. The structure of probe P-1 has been established by single crystal X-ray. The photophysical properties of probe P-1 revealed that the values of the fluorescence quantum yield are higher in non-polar solvents than in polar solvents. Compared with the free P-1, the fluorescence intensity of P-1 shows a significant fluorescence enhancement in the presence of Al3+ without any significant interference from other cations and anions. In addition, from the UV-vis titration, fluorescence titration,Job's plot and 1H NMR spectra analysis, we could primarily confirm that three important coordinative sites of P-1 for Al3+ were from imine nitrogen and tertiary amine nitrogen and formed a 1:1 complex. The fluorescence intensity for the (P-1) showed a good linearity with the concentration of Al3+ in the range of 3.0-10.0 µM, with a detection limit of 8.65 × 10-8 M and a binding constant (Kb) of 4.95 × 104 M-1. It is worthy of note that the probe P-1 was successfully applied in detection of Al3+ in Yellow River and tap water samples.

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Three naphthol Schiff base-type fluorescent sensors, 1,3-Bis(2-hydroxy-1-naphthylideneamino)propane (L1), 1,3-Bis(1-naphthylideneamino)-2-hydroxypropane (L2) and 1,3-Bis(2-hydroxy-1-naphthylideneamino)-2-hydroxypropane (L3), have been synthesized. Their recognition abilities for Al(3+) are studied by fluorescence spectra. Coordination with Al(3+) inhibited the CN isomerization of Schiff base which intensely increase the fluorescence of L1-L3. Possessing a suitable space coordination structure, L3 is a best selective probe for Al(3+) over other metal ions in MeOH-HEPES buffer (3/7, V/V, pH=6.6, 25°C, λem=435nm). A turn-on ratio over 140-fold is triggered with the addition of 1.0 equiv. Al(3+) to L3. The binding constant Ka of L3-Al(3+) is found to be 1.01×10(6.5)M(-1) in a 1:1 complex mode. The detection limit for Al(3+) is 0.05µM. Theoretical calculations have also been included in support of the configuration of the L3-Al(3+) complex. Importantly, the probe L3 has been successfully used for fluorescence imaging in colon cancer SW480 cells.

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Many phytopathogenic fungi form appressoria on some artificial substances. However, it is difficult to induce appressorium-mediated penetration into artificial substances. In the present study, novel artificial agar media were developed to investigate the in vitro penetration process of phytopathogenic fungi. The media contained sodium carboxymethyl cellulose or sodium alginate, and the surfaces were subjected to ionic cross-linking using trivalent metal ions. The hemibiotrophic phytopathogenic fungi, rice blast fungus and cucurbit anthracnose fungus, formed appressoria and penetrated into the surface cross-linked artificial agar media from the base of appressoria. These artificial media appeared to induce fungal infection behaviour that occurred on host plants.

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