A supramolecular oligo[2]rotaxane constructed by orthogonal platinum(Ⅱ) metallacycle and pillar[5]arene-based host–guest interactions

Oligo[n]rotaxanes are one of the most extensively studied categories of mechanically bonded macromolecules.In this study,a supramolecular oligo[2]rotaxane is successfully constructed driven by platinum(Ⅱ)metallacycle and pillar[5]arene-based host–guest interactions in an orthogonal way.The supramolecular oligo[2]rotaxane is further applied in fabricating a light harvesting system.

A novel fused bi-macrocyclic host for sensitive detection of Cr_(2)O_(7)^(2-)based on enrichment effect

Improving the highly selective and sensitive binding of chemosensor to target guest is always very challenging.In order to solve this issue,herein,the enrichment effect was introduced into the design of chemosensor molecule.A novel bi-fused-macrocyclic host molecule BPN1 was synthesized by bridging a pillar[5]arene and a naphthalene diimide(NDI)group through hydrogen-bond-rich chain.In the BPN1,the naphthalimide side ring is outside the cavity of the pillar[5]arene.In addition,Cr(VI)greatly threat human health and the environment due to its severe toxicity,and it is very important to develop effective chemosensor for sensitive and selective detection of Cr_(2)O_(7)^(2-)or its ion pairs.In this paper,the novel bi-fused-macrocyclic host molecule BPN1 can recognize Cr_(2)O_(7)^(2-)with high selectivity and sensitivity.The mechanism of BPN1 recognition of Cr_(2)O_(7)^(2-)was studied through experiments and density functional theory(DFT),the results show that BPN1 could supply enrichment effect to bind Cr_(2)O_(7)^(2-)through multiple weak interactions such as hydrogen bonds and anion-π,and achieve highly sensitive and selective detection of Cr_(2)O_(7)^(2-).It is a significant and feasible strategy for improve high selectivity and sensitivity of host to specific objects by using the enrichment effect of fused bi-macrocyclic.

Structure-property relationship on aggregation-induced emission properties of simple azine-based AIEgens and its application in metal ions detection

In recent twenty years,aggregation-induced emission(AIE),due to its excellent application prospect,has aroused widespread interests.The development of novel and easy to make AIE luminogens(AIEgens)is an attractive subject.For this purpose,it is very important to study the structure-property relationship of AIEgens.Because azine derivatives are easy to synthesis and some of them have nice AIE properties,herein,a series of azine derivatives(ADs)were employed as models to study the influence of different functional groups,electronic effects and structures on the AIE properties of azine derivatives.The AIE mechanism were studied by single crystal analysis,density functional theory(DFT)calculations and so on.The results indicated that the o-hydroxyl aryl substituted azine compounds could show good AIE properties.Meanwhile,the AIE properties of o-hydroxyl aryl substituted azine compounds were also influenced by the electronic effects of the aryl groups in the azine compounds.The o-hydroxyl groups could form intramolecular hydrogen bond with imine group,which play key role to restrict the intramolecular rotation of the aryl groups and act as base stone for the AIE process of this kind compounds.The HOMO-LUMO energy gaps of o-hydroxyl substituted azine are smaller than other homologous compounds,which is agree with the proposed AIE mechanism.Finally,thanks to the AIE properties,the o-hydroxy-substituted azines could be used as efficient Al^(3+)and Cu^(2+)fluorescent chemosensors in different conditions.In addition,test strips based on AD10 has been prepared,which can conveniently detect Cu^(2+)in industrial wastewater.This research supplied a way for the design of novel easy to make AIEgens through simple azine derivatives.

Tuning host-guest binding model by different intramolecular alkyl chain lengths in tripodal hosts:An evidence on structure control supramolecular interactions

Supramolecular chemistry has received considerable attention in host-guest recognition.The structureresponse relationship of host-guest recognition system is a meaningful issue.Herein,a series of tripodal nitrogen mustard derivatives(TMs)have been developed in this paper.By rationally design the intramolecular alkyl chain lengths of host,the host-guest binding model have been successfully tuned,which underwent a transformation fromπ-πto multiple hydrogen bonds.This process enhances the host-guest binding force and recognition efficiency.

Novel conductive metallo-supramolecular polymer AIE gel for multi-channel highly sensitive detection of hydrazine hydrate

Hydrazine hydrate(DH)is an important fine chemical intermediate and as fuel for rockets,however,it also has serious toxic for humans and environment.Developing novel materials and methods for sensitive detection of DH in water and air is an important task.In order to effectively detect DH,a novel conductive supramolecular polymer metallogel(PQ-Ag)has been constructed by the coordination of bis-5-hydroxyquinoline functionalized pillar[5]arene(PQ5)with Ag+.The metallogel PQ-Ag could realize the multi-channel sensitive detection of DH through naked-eye,fluorescence,and electrochemical methods.The lowest limit of detection(LOD)is 0.1 mg/m^(3)in air and 2.68×10^(−8)mol/L in water,which is lower than the standard of the US Environmental Protection Agency(EPA)for DH of maximum allowable concentration in drinking water.More importantly,an electronic device for DH detection based on the metallogel PQ-Ag was designed and prepared,which can realize conveniently and efficiently multi-channel detection and alert of DH through sound and light alarms not only in water but also in air.

Pillar[n]arenes-based materials for detection and separation of pesticides

The effective materials and methods for detection and separation of pesticides are urgently needed because most of pesticides show very harmful influence on life and environment. As a new kind of macrocyclic host compound, pillar[n]arenes show very good performance in the detection and separation of pesticides, especially for paraquat(PQ). For the pesticide detection and separation materials, their structures determine performance. Therefore, this review summarizes the recent progress of pillar[n]arenes-based materials for detection and separation of pesticides covering single/multi-pillar[n]arenes, pillar[n]arenes-based polymers, frameworks, composites, nanomaterials, etc.The structure-performance relationships of these materials have been discussed according to the cavity size, the synergistic or collaboration effect, the structure of the polymer or framework, the substrate of the composites and the size of nanomaterials and so on. Based on these, we also look forward to the future and point out the possible way for improving the pesticides detection sensitivity and separation efficiency of this kind of materials.

Pillar[5]arene and Azine Derivative Assembly Improved Dual-Channel Detection of CN-

The cyanide anion(CN^(–))is known to be one of the most toxic anions.Therefore,there is an urgent need to develop a reliable,sensitive,selective,rapid and effective method for the detection of CN^(–).Here,a self-assembly strategy based on pillar[5]arene P5 and azine derivative AZ was used to construct supramolecular sensors,and it was found that the detection effect of CN^(–)was significantly improved by the assembly strategy.The sensitivity of the assembled sensor P5-AZ to CN^(–)is more than 10 times higher than that of AZ.The detect mechanism was further investigated by theoretical calculations and 1H NMR.The results showed that AZ detects CN–by a deprotonation process with fluorescence enhancement,while P5-AZ improves the sensitivity of CN^(–)recognition through hydrogen bonding,anion-πand anion-dipole interactions,as well as the strong bonding ability of the assembly.Supramolecular assembly P5-AZ has the advantages of low toxicity,high sensitivity,and more importantly,it provides a method to detect CN^(–)sensitivity in the aqueous phase and organisms by host-guest assembly.

Turn-on fluorescence sensing of cyanide ions in aqueous solution

A sensitive fluorescent probe, 2,2＇-bisbenzimidazole （L）, for CN has been developed. This structurally simple receptor displays great selectivity for the cyanide anion over other common inorganic anions in an aqueous environment. In addition, further study demonstrates the lower detection of the fluorescence response of the sensor to CN is in 10 9 mol/L range. Thus, the present probe should be applicable as a practical system for the monitoring of cyanide concentrations in aqueous samples.

Multi-stimuli responsive metal-organic gel of benzimidazol-based ligands with lead nitrate and their use in removal of dyes from waste-water

A novel smart metal-organic gel（MOG） formed from biscarboxyl-functionalized benzimidazole derivative（D11） in the presence of lead nitrate has been investigated.The critical gel concentration for the formation of MOG was just 0.36 wt%,which exhibits a super gelation capability of D11.The coordination of the metal to the ligand D11 was found to play a vital role in the construction of the supramolecular MOG.Microstructures determined by SEM observation demonstrated that the MOG was formed by intertwined fibrils.Interestingly,the MOG exhibits pH-induced,thermo-induced,and chemical-induced reversible gel-sol transition.Meanwhile,this supramolecular MOG shows desirable absorption ability of methyl orange dye molecules in aqueous solution.

A green synthesis of a simple chemosensor that could instantly detect cyanide with high selectivity in aqueous solution

A novel and simple cyanide chemosensor 2-（naphthalen-1-ylmethylene）malononitrile（L） was designed and synthesized via a green chemistry method in water without using any catalyst.The chemosensor showed an excellent sensitivity and selectivity for CN in aqueous solution.The detection limit could be as low as 1.6×10~7 moI/L（0.16μmol/L）,which is far lower than the WHO guideline of 1.9μmol/L cyanide for drink water.

A Pd_(2)L_(4) Metallacage-Cored Supramolecular Amphiphile and Its Application in Dual-Responsive Controllable Release

The construction of multi-responsive supramolecular systems for drug delivery is a challenging task.In this work,a Pd_(2)L_(4) metallacage 1·([BF_(4)]^(−))_(4) with four pyrene units was first designed and synthesized through coordination-driven self-assembly.After the introduction ofγ-CD,a supramolecular amphiphile 1–γ-CD was successfully constructed based on the host–guest molecular recognition betweenγ-CD and the pyrene unit of 1·([BF_(4)]^(−))_(4),which further self-assembled into dual-responsive supramolecular vesicles in aqueous solution.DOX·HCl was used as a model molecule to study the drug encapsulation and release behavior of the supramolecular vesicles.By adjusting the pH of the solution to acidic condition or adding a certain amount ofα-amylase,the vesicle structure was destroyed to achieve rapid and effective release of the drug molecules.This study provides an example for the rational design of efficient dual-responsive supramolecular nanocarriers,which have potential application value in the field of controlled drug delivery.

Influence of Monomers'Structure on the Assembly and Material Property of Pillar[5]arene-Based Supramolecular Polymer Gels

Pillar[5]arene-based supramolecular polymer gels(SPGs)show broad application prospects.To investigate the influence of the supramolecular monomers'structure on the assembly and properties of corresponding pillar[5]arene-based SPGs,a series of monomers based on different functionalized pillar[5]arene derivatives with various structures were synthesized.There are per-methylated pillar[5]arene(H1),bromobutane-functionalized pillar[5]arene(H2),4-hydroxybenzaldehyde-functionalized pillar[5]arene(H3),ethyl thioglycolate-functionalized pillar[5]arene(H4),thioacetylhydrazine-functionalized pillar[5]arene(H5),bola-type bis-pillar[5]arene(H6)and tripodal-type tri-pillar[5]arene(H7).Meanwhile,a neutral tripodal-guest TG was also employed to co-assemble with these pillar[5]arene-based monomers by host-guest interactions.As a result,under the same conditions(10%,DMSO-H_(2)O,w/v,10 mg·mL^(-1)=1%),H1 and H2 cannot assemble into SPGs with TG.Interestingly,mono-p[5]derivatives H3—H5 could assemble into SPGs with TG.More importantly,bis-p[5]H6 and tri-p[5]H7 could assemble into supramolecular polymer network gel(SPNG)and supramolecular polymer organic framework gel(SOFG)with TG,respectively.These gels all show blue aggregation-induced emission(ALE)properties.Among these SPGs,the SPNG shows the best viscoelastic behavior and self-healing properties.The result is attributed to the flexible network structure of SPNGs.In addition,the xerogels of SOFG and SPNG have shown nice adsorption and separation properties for organic dyes in water solution.

A highly selective colorimetric and“Off-On”fluorescence sensor for CN^-based on Zn(salphenazine)complex

The development of sensors for selective detection of cyanide ion(CN^-) is an important mission to accomplish because of the versatility and toxicity of CN^-. In the present work, an "ensemble"-based colorimetric and fluorescent sensor(L2-Zn^(2+)) for CN^-ion has been developed. The addition of cyanide ions removed Zn^(2+) from the ensemble(L2-Zn^(2+)) in aqueous medium, resulting in a color change of the solution from red to buff and a "turn-on" fluorescent response. Also, the sensitivity of both the fluorescenceand colorimetric-based assay is below the maximum allowable level of cyanide ions in drinking water set by the World Health Organization. In addition, test strips, which served as convenient and efficient CN^- test kits, were fabricated based on the sensor.Notably, the selective detection of cyanide with L2-Zn^(2+) for practical application was also performed in sprouting potatoes.