Design strategy and recent progress of fluorescent probe for noble metal ions (Ag, Au, Pd, and Pt)

Mediating sequential turn-on and turn-off fluorescence signals for discriminative detection of Ag+ and Hg2+ via readily available CdSe quantum dots

Realizing the accurate recognition and quantification of heavy metal ions is pivotal but challenging in the environmental, biological, and physiological science fields. In this work, orange fluorescence emitting quantum dots (OQDs) have been facilely synthesized by one-step method. The participation of silver ion (Ag+) can evoke the unique aggregation-induced emission (AIE) of OQDs, resulting in prominent fluorescence enhancement, which is scarcely reported previously. Moreover, the Ag+-triggered turn-on fluorescence can be continuously shut down by mercury ion (Hg2+). This intriguing sequential fluorescence variation exhibits great sensing potency for discrimination and quantification of Ag+ and Hg2+. Meanwhile, our OQDs also exhibit good selectivity, sensitivity, and rapid response toward Ag+ and Hg2+ detection. Due to their high performance, OQDs have been applied to the determination of Ag+ and Hg2+ levels in daily necessities and water samples with satisfactory results. Moreover, a portable smartphone-assisted sensing platform based on chromatic change has been constructed, facilitating the real-time and naked-eye visualization in the resource-confined scene. We anticipate that the discovery of these OQDs would be advantageous for exploring novel QDs materials for fluorescence detection.

The complexometric behavior of selected aroyl-S,N-ketene acetals shows that they are more than AIEgens

Using the established synthetic methods, aroyl-S,N-ketene acetals and subsequent bi- and multichromophores can be readily synthesized. Aside from pronounced AIE (aggregation induced emission) properties, these selected examples possess distinct complexometric behavior for various metals purely based on the underlying structural motifs. This affects the fluorescence properties of the materials which can be readily exploited for metal ion detection and for the formation of different metal-aroyl-S,N-ketene acetal complexes that were confirmed by Job plot analysis. In particular, gold(I), iron(III), and ruthenium (III) ions reveal complexation enhanced or quenched emission. For most dyes, weakly coodinating complexes were observed, only in case of a phenanthroline aroyl-S,N-ketene acetal multichromophore, measurements indicate the formation of a strongly coordinating complex. For this multichromophore, the complexation results in a loss of fluorescence intensity whereas for dimethylamino-aroyl-S,N-ketene acetals and bipyridine bichromophores, the observed quantum yield is nearly tripled upon complexation. Even if no stable complexes are formed, changes in absorption and emission properties allow for a simple ion detection.

Indium nanocubes based recyclable fluorescent chemosensor for sustainable environmental monitoring: pH-induced fluorescence transition and selective detection of Pd(II) ions

Rapid modern industrialization and urbanization have escalated heavy metal pollution, with palladium (Pd2+) raising significant concerns due to its extensive usage in catalysis, hydrogen storage, and electronics, thereby imposing substantial risks on the environment and human health. In this study, we report a highly fluorescent indium nanocubes based chemosensor (InNCs) functionalized with perylene tetracarboxylic acid (PTCA) and 4-(pyridyl)ethenyl benzene (PEB). The InNCs exhibited emission maximum at 415 nm (λex ∼ 350 nm) with robust chemical and photo-stability, and acted as a fluorogenic probe for selective recognition of Pd2+ in aqueous medium. The fluorescence sensing properties of InNCs were thoroughly assessed via different techniques including steady-state absorption, emission and time-resolved emission spectroscopic methods. Among the various competitive analytes, only Pd2+ could induce a significant fluorescence quenching in the probe. This "turn-off" fluorescence sensing demonstrated a remarkably low LoD of ∼65 nM. Notably, with the addition of EDTA, the probe displayed good recyclability upto 4 cycles. The sensory probe was successfully employed as a reusable platform to estimate Pd(II) in different real water and soil samples with considerable accuracy (∼ 5-10 % error). Moreover, the probe exhibited a pH-induced fluorescence transition, indicating its potential to be applied as a pH sensor. The Pd(II) binding and pH-sensing mechanisms have also been elucidated through density functional theory (DFT) calculations.

Iodine Adsorption-Desorption-Induced Structural Transformation and Improved Ag+ Turn-On Luminescent Sensing Performance of a Nonporous Eu(III) Metal-Organic Framework

Posttreatment of pristine metal-organic frameworks (MOFs) with suitable vapor may be an effective way to regulate their structures and properties but has been less explored. Herein, we report an interesting example in which a crystalline nonporous Eu(III)-MOF was transferred to a porous amorphous MOF (aMOF) via iodine vapor adsorption-desorption posttreatment, and the resulting aMOF showed improved turn-on sensing properties with respect to Ag+ ions. The crystalline Eu-MOF, namely, Eu-IPDA, was assembled from Eu(III) and 4,4'-{4-[4-(1H-imidazol-1-yl)phenyl]pyridine-2,6-diyl}dibenzoic acid (H2IPDA) and exhibited a two-dimensional (2D) coordination network based on one-dimensional secondary building blocks. The close packing of the 2D networks gives rise to a three-dimensional supramolecular framework without any significant pores. Interestingly, the nonporous Eu-IPDA could absorb iodine molecules when Eu-IPDA crystals were placed in iodine vapor at 85 °C, and the adsorption capacity was 1.90 g/g, which is comparable to those of many MOFs with large BET surfaces. The adsorption of iodine is attributed to the strong interactions among the iodine molecule, the carboxy group, and the N-containing group and leads to the amorphization of the framework. After immersion of the iodine-loaded Eu-IPDA in EtOH, approximately 89.7% of the iodine was removed, resulting in a porous amorphous MOF, denoted as a-Eu-IPDA. In addition, the remaining iodine in the a-Eu-IPDA framework causes strong luminescent quenching in the fluorescence emission region of the Eu(III) center when compared with that in Eu-IPDA. The luminescence intensity of a-Eu-IPDA in water suspensions was significantly enhanced when Ag+ ions were added, with a detection limit of 4.76 × 10-6 M, which is 1000 times that of pristine Eu-IPDA. It also showed strong anti-interference ability over many common competitive metal ions and has the potential to sense Ag+ in natural water bodies and traditional Chinese medicine preparations. A mechanistic study showed that the interactions between Ag+ and the absorbed iodine, the carboxylate group, and the N atoms all contribute to the sensing performance of a-Eu-IPDA.

Triazole-linked amidopyrene-tagged fluorometric probe for Au3+ ions and pH control aggregation-induced emission

In this paper, an amidopyrene-tagged reversible fluorescence probe 1 has been constructed for the detection of Au(III) ions in H2O/CH3CN (4/1, v/v). It is used to identify the Au(III) ions over several metal ions with excellent sensitivity (LOD: 0.061 µM). The fluorescence quenching of 1 with Au(III) ions might be attributed to the reverse PET process. Probe 1 recognized Au(III) by forming tetravalent geometry with the amide -NH, triazole moiety, free water, and Cl- ion in 1:1 binding mode, which is evidenced by the DFT calculations, FT-IR spectroscopy, and HRMS value of the complex. The application utility of probe 1 was ascertained from the recovery of Au(III) ions from different sources of natural water samples. Interestingly, molecule 1 also showed aggregation-induced emission behavior at basic pH (>10) in H2O/CH3CN medium with high water content. The AIE might be attributed to the formation of self-associates of 1 upon the intermolecular H-bonding interactions between water and donor atom(s) of 1 or the increased polarity of the solvent medium.

Fluorescent and chromogenic organic probes to detect group 10 metal ions: design strategies and sensing applications

Group 10 metals including Ni, Pd and Pt have been extensively applied in various essential aspects of human social life, material science, industrial manufactures, medicines and biology. The ionic forms of these metals are involved in several biologically important processes due to their strong binding capability towards different biomolecules. However, the mishandling or overuse of such metals has been linked to serious contamination of our ecological system, more specifically in soil and water bodies with acute consequences. Therefore, the detection of group 10 metal ions in biological as well as environmental samples is of huge significance from the human health point of view. Related to this, considerable efforts are underway to develop adequately efficient and facile methods to achieve their selective detection. Optical sensing of metal ions has gained increasing attention of researchers, particularly in the environmental and biological settings. Innovatively designed optical probes (fluorescent or colorimetric) are usually comprised of three basic components: an explicitly tailored receptor unit, a signalling unit and a clearly defined reporter unit. This review deals with the recent progress in the design and fabrication of fluorescent or colorimetric organic sensors for the detection of group 10 metal ions (Ni(II), Pd(II) and Pt(II)), with attention to the general aspects for design of such sensors.

A reaction-based scenario for fluorescence probing of Au(III) ions in human cells and plants

A BODIPY-based fluorophore decorated with a gold specific reactive handle (e.g., 2-alkynylallyl alcohol) displayed a ratiometric fluorescence change in response to Au3+ ions with extraordinary selectivity over other competing metal species, including Hg2+, Cu2+, Zn2+ and Pd2+. By way of a gold-catalyzed intramolecular cyclisation-isomerisation reaction sequence, a BODIPY construct with an extended π-conjugation transformed into a new structure with a relatively short π-system. This unique chemical transformation was accompanied by, and resulted in, a dramatic shift in the emission and absorption wavelength, which could be monitored as distinct changes in the color of the solution's emission. Apart from its outstanding analytical performance in solution, including a quick response time (<10 s), unique specificity, a high-fold ratiometric change (62-fold), and a remarkably low detection limit (358 nM), the probe also proved useful in monitoring Au3+ ions in human cells and plants (e.g., Nicotiana benthamiana).

A sensitive ratiometric fluorescence probe with a large spectral shift for sensing and imaging of palladium

Palladium (Pd) is an important heavy metal with excellent catalytic properties and widely used in organic chemistry and the pharmaceutical industry. Efficient and convenient analytical techniques for Pd are urgently needed due to the hazardous effects of Pd on the environment and human health. Herein, we have developed five new ratiometric probes for the selective detection of Pd0 based on the Pd-catalyzed Tsuji-Trost reaction. Among them, the F-substituted probe PF-Pd showed the largest spectral shift (148 nm) and the most sensitive response (detection limit 2.11 nM). PF-Pd was employed to determine Pd0 in tap water or lake water samples, which presented satisfactory accuracy and precision. In addition, profiting from its distinct colorimetric response, visual detection of Pd0 was performed on PF-Pd loaded test strips or in field soil samples. Furthermore, fluorescence imaging of living 4T1 cells demonstrated that PF-Pd is suitable for imaging of intracellular Pd0. The good analytical performance of PF-Pd may enable it to be widely used in the convenient, rapid, sensitive and selective detection of Pd0 in environmental or biological analysis.

Precipitation of Pt, Pd, Rh, and Ru Nanoparticles with Non-Precious Metals from Model and Real Multicomponent Solutions

This article presents studies on the precipitation of Pt, Pd, Rh, and Ru nanoparticles (NPs) from model and real multicomponent solutions using sodium borohydride, ascorbic acid, sodium formate, and formic acid as reducing agents and polyvinylpyrrolidone as a stabilizing agent. As was expected, apart from PGMs, non-precious metals were coprecipitated. The influence of the addition of non-precious metal ions into the feed solution on the precipitation yield and catalytic properties of the obtained precipitates was studied. A strong reducing agent, NaBH₄ precipitates Pt, Pd, Rh, Fe and Cu NPs in most cases with an efficiency greater than 80% from three- and four-component model solutions. The morphology of the PGMs nanoparticles was analyzed via SEM-EDS and TEM. The size of a single nanoparticle of each precipitated metal was not larger than 5 nm. The catalytic properties of the obtained nanomaterials were confirmed via the reaction of the reduction of 4-nitrophenol (NPh) to 4-aminophenol (NAf). Nanocatalysts containing Pt/Pd/Fe NPs obtained from a real solution (produced as a result of the leaching of spent automotive catalysts) showed high catalytic activity (86% NPh conversion after 30 min of reaction at pH 11 with 3 mg of the nanocatalyst).

Analyte-Triggered Excited-State Intramolecular Proton Transfer- Delayed Fluorescence: A General Approach for Time-Resolved Turn-On Fluorescence Imaging

The research of delayed fluorescence (DF) has been a hot topic in biological imaging. However, the development of analyte-triggered small molecule DF probes remains a considerable challenge. Herein a novel excited-state intramolecular proton transfer-delayed fluorescence (ESIPT-DF) approach to construct analyte-stimulated DF probes was reported. These new classes of ESIPT-DF luminophores were strategically designed and synthesized by incorporating 2-(2'-hydroxyphenyl)benzothiazole (HBT), a known ESIPT-based fluorophore, as acceptor with a series of classic donor moieties, which formed a correspondingly twisted donor-acceptor pair within each molecule. Thereinto, HBT-PXZ and HBT-PTZ exhibited significant ESIPT and DF characters with lifetimes of 5.37 and 3.65 μs in the solid state, respectively. Furthermore, a caged probe HBT-PXZ-Ga was developed by introducing a hydrophilic d-galactose group as the recognition unit specific for β-galactosidase (β-gal) and ESIPT-DF blocking agent and applied to investigate the influence of metal ions on β-gal activity on the surface of Streptococcus pneumoniae as a convenient tool. This ESIPT-DF "turn-on" approach is easily adaptable for the measurement of many different analytes using only a predictable modification on the caged group without modification of the core structure.

AIEE Active Azomethine-Based Rhodamine Derivative For Ultrasensitive Multichannel Detection of Au3+ Through a Fluorimetrically, Electrochemically, and RGB-Based Sensing Assay

In this study, a novel rhodamine-based optically and electrochemically active chemosensor, integrated with a p-DMAC moiety, demonstrated extremely selective identification of Au³⁺ ions relative to other metal species, including (Li⁺, Na⁺, K⁺, Ba²⁺, Ca²⁺, Mg²⁺, Co²⁺, Mn²⁺, Zn²⁺, Pb²⁺, Ni²⁺, Fe²⁺, Hg²⁺, Fe³⁺, Cd²⁺, Pd²⁺, Al³⁺, Cr³⁺, Cu²⁺, and nitrate salt of Ag⁺). These compounds demonstrated a novel and outstanding aggregation-induced emission enhancement (AIEE) behavior by aggregating in DMF/H₂O medium. Furthermore, the degree of quenching was varying linearly with a Au³⁺ concentration from 0 to 40 nM, with a lower detection limit by RH-DMAC nanoaggregates of 118.79 picomolar (40.35 ppm). The Stern-Volmer plots, Job's plot, Benesi-Hildebrand plot, ¹H NMR titrations, ESI-mass, and FTIR all revealed significant interactions between the sensor and Au³⁺. Moreover, the proposed electrochemical sensor afforded a linear correlation before the peak current and concentration of Au³⁺ in the range of 0-40 nM, with a detection limit of 483.73 pM or 164.36 ppt (by cyclic voltammetry method) and 298.0 pM or 101.24 ppt (by the Differential Pulse Voltammetry method). Furthermore, the proposed sensing assay was used to measure Au³⁺ ion in spiked water samples (tap, drinking, waste, and river water), achieving acceptable accuracy and precision with high recovery rates. Furthermore, RH-DMAC-coated fluorescence paper test strips were designed for on-site Au³⁺ detection. Apart from this, the use of smartphone-based RGB (Red Green Blue) color analysis shortened the operating process, accelerated the detection technique, and provided a novel methodology for the instantaneous, real-time examination of Au³⁺ in real water samples.

Dicoumarin with dimethyl thiocarbamate in the fluorescent detecting for Au3+ in water and cells

Gold ions have high activity and cytotoxicity completely different from elemental gold. It is necessary and critical to develop Au³⁺ detection tools that are easy to operate, intuitive, inexpensive, and non-destructive testing. Here, we propose a novel two-photon fluorescent probe named DA for detecting Au³⁺, which is a rare combination of dicoumarin with dimethylthiocarbamate for the first time. Based on the PET mechanism, DA turns-on the fluorescence to yellow-green after specifically binds to Au³⁺, and the reaction is completed within 5 min. The detection limit is as low as 27.60 nM. Simultaneously, DA achieved qualitative and quantitative detection of Au³⁺ in environmental water samples, and fluorescence imaging of Au³⁺ in biological cells.

Highly selective fluorescence detection of Pt4+ over Pd2+ and Pt2+ using a polyethyleneimine-based nanosensor prepared via facile three-component reaction

A novel polyethyleneimine (PEI)-based polymeric nanosensor (named PEIMP) was developed for specific fluorescence enhanced sensing of Pt⁴⁺ ion in aqueous media. The sensor was fabricated via "one-pot" three-component reaction using ortho-phthalaldehyde (OPA), PEI and mercaptopurine as raw materials, by which the formation of isoindole fluorophore and its chemical grafting onto PEI chain were achieved simultaneously. The morphology, size and structure of PEIMP have been characterized by various techniques. In buffered aqueous solution (pH 7.0), PEIMP had the ability to specifically bind with Pt⁴⁺ producing notable increase in fluorescence emission at 463 nm (excited at 395 nm). Based on investigations on the sensing mechanism, the fluorescence turn-on response towards Pt⁴⁺ was attributed to the binding of Pt⁴⁺ with purine group in PEIMP resulting in the inhibition of photoinduced electron transfer from purine to isoindole fluorophore. Under the optimal conditions (pH 7.0, incubated at 37 ℃ for 20 min) the detection of Pt⁴⁺ could be achieved with the linear range of 0.1-10 μM and the detection limit of 80 nM. The sensor had the advantages of low-cost raw materials, simple and environmental-friendly synthesis and analytical detection procedures. What's more, it could selectively and sensitively detect Pt⁴⁺ without the effects from common transition metal ions (Pb²⁺, Fe³⁺, Cr³⁺, Al³⁺, Ag⁺, Co²⁺, Hg²⁺, Cd²⁺, Cu²⁺, Mg²⁺, Ni²⁺, Mn²⁺, Zn²⁺), especially precious metalions of Pt²⁺ and Pd²⁺. The proposed method had been successfully applied to quantify Pt⁴⁺ in wastewater and urine samples, and also proved to be potential for monitoring Pt⁴⁺ in biological systems.

Rhodamine-Based Fluorescent Probe for Highly Selective Determination of Hg2

The determination of mercuric ions (Hg²⁺) in environmental and biological samples has attracted the attention of researchers lately. In the present work, a novel turn-on Hg²⁺ fluorescent probe utilizing a rhodamine derivative had been constructed and prepared. The probe could highly sensitively and selectively sense Hg²⁺. In the presence of excessive Hg²⁺, the probe displayed about 52-fold fluorescence enhancement in 50% H₂O/CH₃CH₂OH (pH, 7.24). In the meantime, the colorless solution of the probe turned pink upon adding Hg²⁺. Upon adding mercuric ions, the probe interacted with Hg²⁺ and formed a 1:1 coordination complex, which had been the basis for recognizing Hg²⁺. The probe displayed reversible dual colorimetric and fluorescence sensing of Hg²⁺ because rhodamine's spirolactam ring opened upon adding Hg²⁺. The analytical performances of the probe for sensing Hg²⁺ were also studied. When the Hg²⁺ concentration was altered in the range of 8.0 × 10^-8 to 1.0 × 10^-5 mol L^-1, the fluorescence intensity showed an excellent linear correlation with Hg²⁺ concentration. A detection limit of 3.0 × 10^-8 mol L^-1 had been achieved. Moreover, Hg²⁺ in the water environment and A549 cells could be successfully sensed by the proposed probe.

Novel NBN-Embedded Polymers and Their Application as Fluorescent Probes in Fe3+ and Cr3+ Detection

The isosteric replacement of C═C by B–N units in conjugated organic systems has recently attracted tremendous interest due to its desirable optical, electronic and sensory properties. Compared with BN-, NBN- and BNB-doped polycyclic aromatic hydrocarbons, NBN-embedded polymers are poised to expand the diversity and functionality of olefin polymers, but this new class of materials remain underexplored. Herein, a series of polymers with BNB-doped π-system as a pendant group were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization from NBN-containing vinyl monomers, which was prepared via intermolecular dehydration reaction between boronic acid and diamine moieties in one pot. Poly{2-(4-Vinylphenyl)-2,3-dihydro-1H-naphtho[1,8-de][1,3,2]diazaborinine} (P1), poly{N-(4-(1H-naphtho[1,8-de][1,3,2]diazaborinin-2(3H)-yl)phenyl)acrylamide} (P2) and poly{N-(4-(1H-benzo[d][1,3,2]diazaborol-2(3H)-yl)phenyl)acrylamide} (P3) were successfully synthesized. Their structure, photophysical properties and application in metal ion detection were investigated. Three polymers exhibit obvious solvatochromic fluorescence. As fluorescent sensors for the detection of Fe³⁺ and Cr³⁺, P1 and P2 show excellent selectivity and sensitivity. The limit of detection (LOD) achieved by Fe³⁺ is 7.30 nM, and the LOD achieved by Cr³⁺ is 14.69 nM, which indicates the great potential of these NBN-embedded polymers as metal fluorescence sensors.

Chemical Design of Activatable Photoacoustic Probes for Precise Biomedical Applications

Photoacoustic (PA) imaging technology, a three-dimensional hybrid imaging modality that integrates the advantage of optical and acoustic imaging, has great application prospects in molecular imaging due to its high imaging depth and resolution. To endow PA imaging with the ability for real-time molecular visualization and precise biomedical diagnosis, numerous activatable molecular PA probes which can specifically alter their PA intensities upon reacting with the targets or biological events of interest have been developed. This review highlights the recent developments of activatable PA probes for precise biomedical applications including molecular detection of the biotargets and imaging of the biological events. First, the generation mechanism of PA signals will be given, followed by a brief introduction to contrast agents used for PA probe design. Then we will particularly summarize the general design principles for the alteration of PA signals and activatable strategies for developing precise PA probes. Furthermore, we will give a detailed discussion of activatable PA probes in molecular detection and biomedical imaging applications in living systems. At last, the current challenges and outlooks of future PA probes will be discussed. We hope that this review will stimulate new ideas to explore the potentials of activatable PA probes for precise biomedical applications in the future.

Activity-based NIR fluorescent probes based on the versatile hemicyanine scaffold: design strategy, biomedical applications, and outlook

The discovery of a near-infrared (NIR, 650-900 nm) fluorescent chromophore hemicyanine dye with high structural tailorability is of great significance in the field of detection, bioimaging, and medical therapeutic applications. It exhibits many outstanding advantages including absorption and emission in the NIR region, tunable spectral properties, high photostability as well as a large Stokes shift. These properties are superior to those of conventional fluorogens, such as coumarin, fluorescein, naphthalimides, rhodamine, and cyanine. Researchers have made remarkable progress in developing activity-based multifunctional fluorescent probes based on hemicyanine skeletons for monitoring vital biomolecules in living systems through the output of fluorescence/photoacoustic signals, and integration of diagnosis and treatment of diseases using chemotherapy or photothermal/photodynamic therapy or combination therapy. These achievements prompted researchers to develop more smart fluorescent probes using a hemicyanine fluorogen as a template. In this review, we begin by describing the brief history of the discovery of hemicyanine dyes, synthetic approaches, and design strategies for activity-based functional fluorescent probes. Then, many selected hemicyanine-based probes that can detect ions, small biomolecules, overexpressed enzymes and diagnostic reagents for diseases are systematically highlighted. Finally, potential drawbacks and the outlook for future investigation and clinical medicine transformation of hemicyanine-based activatable functional probes are also discussed.

Syntheses, crystal structures and Hirshfeld surface analysis of (Z)-3-[(3-acetyl-2-hydroxyphenyl)amino]-2-bromoprop-2-enal and a novel ZnII complex

A novel zero-dimensional dinuclear zinc complex, di-μ-acetato-1:2κ4 O:O′-(μ-2-acetyl-6-{[(Z)-2-bromo-3-oxoprop-1-en-1-yl]azanidyl}phenolato-1κ2 O 1,O 2:2κ3 O 1,N,O 6)(N,N-dimethylacetamide-1κO)dizinc(II), [Zn2(C11H8BrNO3)(CH3COO)2(C4H9NO)] or [Zn2(L)(CH3COO)2(DMA)], 1, was synthesized using (Z)-3-[(3-acetyl-2-hydroxyphenyl)amino]-2-bromoprop-2-enal (H2 L), which was synthesized from 1-(3-amino-2-hydroxyphenyl)ethanone and 2-bromomalonaldehyde. H2 L and 1 were characterized by single-crystal X-ray diffraction, FT–IR spectroscopy and elemental analysis. Theoretical calculations of the bond orders and excited state of H2 L confirmed that there is extensive electron delocalization in the H2 L molecules. Single-crystal X-ray diffraction shows that the two Zn atoms are pentacoordinated in distorted trigonal bipyramidal configurations in the crystals of 1. The thermogravimetric analysis of 1 shows that the main frame of the complex remains stable to about 190 °C. Powder X-ray diffraction (PXRD) analysis shows that 1 possesses high purity and acid and alkali resistance. The intermolecular interactions of H2 L and 1 were analyzed using Hirshfeld surface analysis and the results indicate that the H...H and O...H interactions of H2 L and 1 play a considerable role in stabilizing the self-assembly process.

A novel AIE fluorescent probe based on myrtenal for Cu2+ detection in a near-perfect aqueous medium and bioimaging in vegetables and zebrafish

An AIE-active fluorescent probe MHTS with good sensitivity and selectivity for the detection of Cu2+ was synthesized from myrtenal.