Clamparene: Synthesis, Structure, and Its Application in Spontaneous Formation of 3D Porous Crystals.

Macrocyclic arenes have emerged as pivotal scaffolds in supramolecular chemistry. Despite their significant contributions to molecular recognition and diverse applications, challenges persist in the development of macrocyclic arene-based crystalline materials, particularly in achieving porosity and addressing limitations in adsorption efficiency resulting from the small cavity sizes of existing macrocyclic arenes. In this study, we present the design and synthesis of a novel macrocyclic arene, clamparene (CLP), featuring a rigid backbone, easy synthesis, and a sizable cavity. CLP self-assembles into one-dimensional sub-nanotubes that further organize into a three-dimensional porous framework in the solid state. The crystalline solid of CLP exhibits potential as a porous crystalline adsorbent for various benzene-based contaminants with rapid adsorption kinetics, large uptake amounts, and good recyclability.

A Two-Step Fluorescence-Resonance Energy Transfer System Constructed by Platinum(II) Metallacycle Based Molecular Recognition.

Considerable progress in the construction of efficient fluorescence-resonance energy transfer (FRET) systems has promoted the development of artificial energy transfer materials. However, despite recent advances, the exploration of efficient and easy strategies to fabricate novel supramolecular systems with FRET activities is still a challenge. Here, we report that a two-step FRET system was successfully achieved, driven by platinum metallacycle based host-guest interactions. The two-step FRET system is used for the preparation of a white-light-emitting diode and serves as a nanoreactor for the photosynthetic process. This work offers a strategy for the fabrication of FRET systems and opens opportunities for functional materials constructed by platinum(II) metallacycle based host-guest interactions.

Platinum Metallacycle-Based Molecular Recognition: Establishment and Application in Spontaneous Formation of a [2]Rotaxane with Light-Harvesting Property.

Macrocyclic molecule-based host-guest systems, which provide contributions for the design and construction of functional supramolecular structures, have gained increasing attention in recent years. In particular, platinum(II) metallacycle-based host-guest systems provide opportunities for chemical scientists to prepare novel materials with various functions and structures due to the well-defined shapes and cavity sizes of platinum(II) metallacycles. However, the research on platinum(II) metallacycle-based host-guest systems has been given little attention. In this article, we demonstrate the host-guest complexation between a platinum(II) metallacycle and a polycyclic aromatic hydrocarbon molecule, naphthalene. Taking advantage of metallacycle-based host-guest interactions and the dynamic property of reversible Pt coordination bonds, a [2]rotaxane is efficiently prepared by employing a template-directed clipping procedure. The [2]rotaxane is further applied to the fabrication of an efficient light-harvesting system with multi-step energy transfer process. This work comprises an important supplement to macrocycle-based host-guest systems and demonstrates a strategy for efficient production of well-defined mechanically interlocked molecules with practical values.

Efficient detection of L-aspartic acid and L-glutamic acid by self-assembled fluorescent microparticles with AIE and FRET activities.

Amino acids play an important role in the formation of proteins, enzymes, hormones and peptides in animals. Moreover, aspartic acid and glutamic acid have a critical impact on the central nervous system as excitatory neurotransmitters. Here, we report the highly selective detection of L-glutamic acid (L-Glu) and L-aspartic acid (L-Asp) using fluorescent microparticles constructed by the combination of aggregation-induced emission and self-assembly-induced Förster resonance energy transfer.

Fluorinated leaning pillar[6]arene: synthesis, structure and selective iodide anion binding by anion-π interactions.

Anion recognition has continuously attracted significant attention due to its important role in environmental and biological sciences. Here, we have designed and synthesized an electron-deficient fluorinated leaning pillar[6]arene 1 that contains two tetrafluoro-benzene units. The electron-deficient fluorinated leaning pillar[6]arene 1 is capable of selectively recognizing iodide anions to form a host-guest complex with 1 : 1 stoichiometry driven by anion-π interactions. Our work ascribes this selective recognition to the preorganization of macrocycles, suitable cavity size, and the effect of anion-π interactions. The innovative application of this macrocycle offers us a new avenue for the design of selective receptors for anions and electron-deficient macrocyclic arenes.

An Organoplatinum(II) Metallacycle-Based Supramolecular Amphiphile and Its Application in Enzyme-Responsive Controlled Release.

Enzyme-responsive nanomaterials are emerging as important candidates for bioanalytical and biomedical applications due to their good biocompatibilities and sensitivities. However, the lack of promising operation platforms compatible with enzyme responsiveness greatly limits the scope and functionality of smart materials. Herein, we report the design and synthesis of a naphthalene-functionalized organoplatinum(II) metallacycle 1 by means of coordination-driven self-assembly, which is subsequently exploited as the organometallic platform to enable enzyme-responsive supramolecular materials. Specifically, a [2 + 2] self-assembled metallacycle 1 first self-assembles into nanosheets in aqueous solution, which can further transform into vesicles with the introduction of ß-cyclodextrin (ß-CD) because of the formation of a bola-type supramolecular amphiphile ß-CD-1. Interestingly, these vesicles show rare α-amylase responsiveness, as demonstrated by structurally transforming back into nanosheets after the addition of α-amylase to their solutions due to the enzyme-induced degradation of cyclodextrins. We also demonstrate the potential application of the self-assembled vesicles in amylase-responsive controlled release.

Detection of Aliphatic Aldehydes by a Pillar[5]arene-based Fluorescent Supramolecular Polymer with Vaporchromic Behavior.

The detection of volatile aliphatic aldehydes is of significance because of their chemical toxicity, physical volatility and widespread applications in chemical industrial processes. In this work, the direct detection of aliphatic aldehydes is tackled using a pillar[5]arene-based fluorescent supramolecular polymer with vaporchromic behavior. Thin films with strong orange-yellow fluorescence are prepared by coating the linear supramolecular polymer on glass sheets. When the thin films are exposed to aliphatic aldehydes with different carbon chain lengths, they can selectively sensing n-butyraldehyde (C4 ) and caprylicaldehyde (C8 ), accompanied by fluorescence quenching, indicating that the supramolecular polymer is a highly selective vapochromic response material for aliphatic aldehydes with long alkyl chains.

A rhodamine-based dual chemosensor for the naked-eye detection of Hg2+ and enhancement of the fluorescence emission for Fe3.

A novel fluorescent chemosensor based on trimesoyl chloride-rhodamine (TR) was successfully synthesized. Rising chromogenic and fluorogenic spectral enhancements could be observed in trimesoyl chloride-rhodamine (TR) probes when Hg2+ and Fe3+ were added, respectively. TR has shown selectivity for Hg2+ and Fe3+ with high sensitivity due to metal ion complexation induced photophysical "turn-on" signaling responses. The detection limit towards Hg2+ was 2.46 × 10-8 M as determined by the 3σ method. At the same time, fluorogenic spectral enhancements were observed in TR, which exhibits a superior sensitive and selective recognition towards Fe3+ with 4.11 × 10-8 M of the detection limit. The test strips were used for colorimetric and simple detection towards Hg2+, which might finally enable the advancement of the Hg2+ sensor in the field of on-site detection.

A fluorescent supramolecular gel and its application in the ultrasensitive detection of CN- by anion-π interactions.

Supramolecular gels have been widely reported on account of their unique superiority and application prospects. In this work, we constructed a novel supramolecular gel (HD-G) by using hydroxy-naphthaldehyde decorated with naphthalimide in DMSO solution, which exhibited excellent selectivity and ultrasensitive sensing properties toward CN- (the lowest detection limit is 1.82 × 10-10 M). The sensing mechanism of this supramolecular gel takes advantage of π-π stacking interactions and anion-π interactions, which is different from the other familiar methods.

Tailoring an HSO4- anion hybrid receptor based on a phenazine derivative.

A catechol-functionalized phenazine imidazole (PD) was tailored with 2,3-diaminophenazine and 3,4-dihydroxy benzaldehyde, and it served as a hybrid acceptor for capturing HSO4- anions. The selectivity and sensitivity of the PD receptor for anion sensing were studied. It was found that the PD receptor could not only display a preferable sensitivity to HSO4- ions with a "turn-off" fluorescence response, but also have a strong anti-interference ability toward other common anions, especially basic anions such as CH3COO-, HPO42-, and H2PO4-. The anion recognition mechanism of PD towards HSO4- is based on multiple hydrogen bond interactions. Finally, the strips for anion detection were prepared, which were verified to be a convenient and high-efficiency test kit for detecting HSO4- ions with the naked eye.

Th4+ tuned aggregation-induced emission: A novel strategy for sequential ultrasensitive detection and separation of Th4+ and Hg2.

A novel strategy, Th4+ tuned aggregation-induced emission, for sequential ultrasensitive detection and separation of Th4+ and Hg2+ was developed successfully. For demonstration this strategy, we designed and synthesized two tripodal gelators TH (tri-(isoniazid-4-yl)-functionalized trimesic acylhydrazine) and TA (tri-(pyridine-4-yl)-functionalized trimesic amide). The TH and TA could assemble into a stable supramolecular polymer hydrogel THTA-G in DMSO/H2O (3.3:6.7, v/v) binary-solution. The THTA-G does not show aggregation-induced emission (AIE) effect. However, after addition of Th4+ into the THTA-G, the obtained metallogel THTA-GTh shows strong green AIE effect, which indicated that Th4+ could tune the gel generation of AIE effect. Interestingly, the THTA-G could ultrasensitive fluorescently detect Th4+, and the corresponding metallogel THTA-GTh could ultrasensitively detect Hg2+. The detection limits of THTA-G and THTA-GTh for Th4+ and Hg2+ are 8.61 × 10-11 mol/L and 1.08 × 10-11 mol/L, respectively. Additionally, the xerogels of THTA-G and THTA-GTh could separate Th4+ and Hg2+ from aqueous solution with excellent ingestion capacity, and the THTA-G could be used as a writable smart light-emitting material.

In Situ Generation of AgI Quantum Dots by the Confinement of A Supramolecular Polymer Network: A Novel Approach for Ultrasensitive Response.

A novel approach for in situ generation of AgI quantum dots by the confinement of a pillar[5]arene-based supramolecular polymer network has been successfully developed. The supramolecular polymer network (SPN-QP) was constructed by using a bis-8-hydroxyquinoline-modified pillar[5]arene derivative as a host (H-QP) and a bis-pyridinium-modified decane as guest (G-PD). The SPN-QP shows ultrasensitive response for Ag+ . The limit of detection is about 7.44×10-9  M.. Interestingly, when I- was added to the SPN-QP+Ag+ system, an unexpected strong warm-white fluorescence emission was observed. After carefu investigation, we found that the strong warm-white fluorescence emission could be attributed to the in situ formation of AgI quantum dots under the confinement of the supramolecular polymer network (SPN-QP). Based on this approach, ultrasensitive detection of I- was realized. The limit of detection for I- is 4.40×10-9  M. This study provides a new way for the preparation of quantum dots under the confinement of supramolecular polymer network as well as ultrasensitive detection of ions by in situ formation of quantum dots.

Competition of cation-π and exo-wall π-π interactions: a novel approach to achieve ultrasensitive response.

A novel approach to achieve ultrasensitive response was successfully developed by rationally introducing the competition between cation-π and exo-wall π-π interactions into a pillar[5]arene-based supramolecular organogel (P5N-OG). Interestingly, the P5N-OG could be used for ion detection and separation, fluorescent display materials as well as ultrasensitive logic gates.

A novel pillar[5]arene-based supramolecular organic framework gel to achieve an ultrasensitive response by introducing the competition of cationπ and ππ interactions.

Ultrasensitive response properties are an intriguing concern for stimuli-responsive materials. Herein, we report a novel method to achieve an ultrasensitive response by introducing the competition of cationπ and ππ interactions into a pillar[5]arene-based supramolecular organic framework (SOF-AMP). SOF-AMP was constructed with a novel bis-naphthalimide functionalized pillar[5]arene, which was able to form a stable supramolecular gel (SOF-AMP-G) in cyclohexanol. Interestingly, SOF-AMP-G shows an ultrasensitive response to Fe3+ through the competition of cationπ and ππ interactions. Meanwhile, the Fe3+ coordinated SOF (MSOF-Fe) shows an ultrasensitive response to H2PO4-. SOF-AMP-G displayed yellow fluorescence whereas, after the addition of 0.5 equiv. of Fe3+ to SOF-AMP-G, the yellow fluorescence was quenched. The detection limit of SOF-AMP-G for Fe3+ is 7.54 × 10-9 M. More interestingly, the Fe3+ coordinated SOF gel (MSOF-Fe-G) could sense H2PO4- with a fluorescence "turn-on". The detection limit of MSOF-Fe-G for H2PO4- is 4.21 × 10-9 M. Simultaneously, the Fe3+ and H2PO4- responsive thin films based on these SOF gels were prepared. Moreover, these SOF gels could be used as ultrasensitive ion sensors, fluorescent display materials and sensitive logic gates.

The Antioxidant Inhibition of Clove Effective Fraction on Lipid, Protein and Spectra Variation of LDL.

Oxidation of low density lipoprotein (LDL) has been considered as the critical factor which led to atherosclerosis (AS). Lipid and protein in LDL were oxidized to cause change of spectra during oxidation. Clove has been demonstrated to possess the strongest antioxidant capacity among 87 both medical and edible plants proclaimed by China. However, whether LDL oxidation is inhibited by clove? If so, whether it inhibits the oxidation of lipid and protein in LDL, and how does spectral characteristic of LDL change during oxidation when clove was added into LDL. Currently, these questions are still unclear. Therefore, the inhibition efficiency of the effective fraction from clove (EFC) on oxidation of LDL was studied by UV-Visible spectra and fluorescence spectra. The results indicated that EFC might effectively delay propagation of conjugated diene (CD) during LDL oxidation and postpone reaching maximum of its content. Likewise, it might inhibit cholesterol degradation, tryptophan (Trp) fluorescence quenching, lysine (Lys) residues from being modified, and lipofuscins from being generated in peroxidatic reaction among lipid and protein. Besides, EFC also might affect variation of UV-Visible spectra of LDL during oxidation. This study provides reference for future research and development of clove functional food inhibiting AS.

Phenazine-based colorimetric and fluorescent sensor for the selective detection of cyanides based on supramolecular self-assembly in aqueous solution.

Taking advantages of both the well-known phenazine structure and the mechanism of the supramolecular self-assembly and deprotonation process, the fluorescent and colorimetric sensor (ZL) was designed and synthesized, behaving as a circulation utilization (above 10 times) receptor for selective detection of cyanide anion (CN-) in aqueous media. Upon the addition of CN-, the sensor displayed obvious color changes from yellow to jacinth by naked eyes and the fluorescence immediately quenched (<10s). With respect to other common anions, the sensor possessed high selectivity and sensitivity (0.05µM) for cyanide anions. In addition, the test strips of ZL were fabricated, which could serve as practical colorimetric and fluorescent sensor for "in-the-field" measurements.

A highly selective fluorescent chemosensor for iron ion based on 1H-imidazo [4,5-b] phenazine derivative.

Two kinds of fluorescent sensors (S and S1) for Fe(3+) bearing 1H-Imidazo [4,5-b] phenazine derivatives have been designed and synthesized. Between the two sensors, S showed excellent fluorescent specific selectivity and high sensitivity for Fe(3+) in DMSO solution. The test strip based on S was fabricated, which could act as a convenient and efficient Fe(3+) test kit. The recognition mechanism of the sensor toward Fe(3+) was evaluated by MS, IR and XRD. The detection limit of the sensor S towards Fe(3+) is 4.8×10(-6)M. And other cations, including Hg(2+),Ag(+), Ca(2+), Cu(2+), Co(2+), Ni(2+), Cd(2+), Pb(2+), Zn(2+), Cr(3+), and Mg(2+) had no influence on the probing behavior.