Aggregation-Induced Emission Supramolecular Organic Framework

Research Article Cite This: ACS Sustainable Chem. Eng. 2019, 7, 11999−12007

pubs.acs.org/journal/ascecg

Aggregation-Induced Emission Supramolecular Organic Framework (AIE SOF) Gels Constructed from Supramolecular Polymer Networks Based on Tripodal Pillar[5]arene for Fluorescence Detection and Efficient Removal of Various Analytes Juan Liu,*,† Yan-Qing Fan,‡ Shan-Shan Song,‡ Guan-Fei Gong,‡ Jiao Wang,‡ Xiao-Wen Guan,‡ Hong Yao,‡ You-Ming Zhang,‡ Tai-Bao Wei,*,‡ and Qi Lin*,‡ Downloaded via GUILFORD COLG on July 18, 2019 at 10:10:09 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

†

College of Chemical Engineering, Northwest Minzu University (Northwest University for Nationalities), Xibei Xincun, Lanzhou 730000, China ‡ Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Anning East Road, Lanzhou 730070, China S Supporting Information *

ABSTRACT: Herein, an aggregation-induced emission (AIE) supramolecular organic framework gel (SOF-TPN-G) was successfully constructed from novel supramolecular polymer networks based on tripodal pillar[5]arene. The SOF-TPN-G shows fluorescent response for multiple metal ions. Interestingly, by introducing Fe3+, Cu2+, Cr3+, Ag+, Tb3+, and Eu3+ into the SOF-TPN-G, respectively, a series of metallogels (SOF-Ms) with multicolor fluorescence was obtained. Moreover, based on these gels, an eight-unit sensor array was successfully developed, which exhibits a highly sensitive fluorescent response for Fe3+, Cu2+, Cr3+, Ag+, Tb3+, Eu3+, F−, CN−, HSO4−, His, Ser, and Cys. Among them, the detection for Fe3+, Cr3+, Tb3+, Eu3+, CN−, F− and Ser reached an ultrasensitive level: the lowest limits of detection (LODs) for these ions and molecules are 7.90 × 10−9, 9.20 × 10−9, 6.60 × 10−9, 6.80 × 10−10, 3.83 × 10−9, 3.26 × 10−9, and 3.37 × 10−9 M, respectively. More importantly, the xerogel of SOF-TPN-G exhibits nice adsorption capacity for multimetal ions (Fe3+, Ag+, Cr3+, Tb3+, Cu2+, and Eu3+), the absorption percentages for them were 98.30%, 99.57%, 98.80%, 98.30%, 99.34% and 98.40%, respectively. These AIE organogel/metallogels are novel multiresponsive fluorescent materials for high-efficiency detection and separation of multianalytes. KEYWORDS: sensor array, supramolecular organic framework, multianalyte detection and removal, tripillar[5]arene, AIE fluorescence, hierarchical assemblies

■

INTRODUCTION In the past decade, aggregation-induced emission (AIE)1 has been shown to have fascinating prospects in many fields, such as biological probes,2,3 chemical sensing,4,5 optoelectronic systems,6,7 stimuli responses,8,9 and so on. As an intriguing photophysical phenomenon related to chromophore aggregation, the AIE was first defined by Tang10 and brought into great focus. Meanwhile, the AIE is also a luminescent phenomenon. Because of the restriction of intramolecular motions (such as intramolecular rotation, intramolecular vibration, and so on), the aggregated molecule shows a luminescence property with an enhanced trend.10 In addition, the AIE materials have also aroused great interest, because of their characteristic photophysical properties.11−13 Recently, supramolecular organic frameworks (SOFs)14−17 have exhibited bright prospects in gas storage,18,19 the separation and sensing of ions or molecules,20 catalysis,21 © 2019 American Chemical Society

and so on. Generally, SOFs were constructed from the assembly of low-molecular-weight organic building blocks through noncovalent interactions, containing hydrogen bonds, π−π interaction, CH−π interaction, and so on.22 The SOFs with excellent self-assembly nature usually possess great potential to form AIE materials.23 Meanwhile, because of the existing of series noncovalent interactions, multiple selfassembly model, and functionality of the organic building blocks, the SOFs usually possess a flexible nature and multistimuli-response properties. Moreover, this property also endows the SOFs-based AIE materials with the capability of tune emission. However, reports on stimuli-responsive SOF materials with tunable AIE are very rare. Received: January 23, 2019 Revised: May 13, 2019 Published: May 23, 2019 11999

DOI: 10.1021/acssuschemeng.9b00452 ACS Sustainable Chem. Eng. 2019, 7, 11999−12007

Research Article

ACS Sustainable Chemistry & Engineering Furthermore, since Ogoshi et al. first reported pillar[n]arenes in 2008,24 the pillar[n]arenes have also attracted considerable attention in the field of supramolecular chemistry. Pillar[n]arenes could supply a series of noncovalent bonds, such as cation−π, π−π, CH−π, inclusion interactions, and so on.25−29 Therefore, pillar[n]arenes show great selective binding abilities for many guests,30,31 which provides a new opportunity for the development of SOFs-based stimuliresponsive AIE materials.32 It is well-known that metal ions and amino acids are fundamental substances in chemical, biological, and environmental fields.33,34 It is distinctly important to selectively recognize and detect special analytes, as well as separate toxic ions.35 For instance, heavy-metal ions and rare-earth-metal ions could be extensively applied in catalysts, optical fields, and so on.36 However, these ions also have an important impact for life systems. Furthermore, amino acids also affect human health and other biologies.37,38 For example, the Cysteine (Cys)containing sulfhydryl group plays distinctly important roles in physiological and pathological processes.39,40 Therefore, it is an intriguing issue to explore novel approachs for sensing these group with high efficiency or removing such ions or molecules from biological or environmental systems. More importantly, because of the powerful detection ability of sensor arrays, sensor array-based multianalyte sensing has become one of the most intriguing issues.41,42 Generally, the sensor array is composed of multiple sensors that can sense and detect a large number of analytes.43−47 Todate, there have been many reports on sensor arrays48−51 for sensing ions,52 molecules,53−56 cells,57 and so on. However, the development of novel sensor arrays through a simple and efficient way is still an attractive challenge. Interestingly, the SOFs-based stimuliresponsive AIE material offers a new approach for design novel sensor array. Inspired by these and other interesting reports in host−guest chemistry,58−61 as well as supramolecular materials,62−65 we herein report a novel AIE organogel obtained from a supramolecular organic framework (SOF-TPN, see Figure 1). The SOF-TPNs were constructed from supramolecular polymer networks (SPNs), which were assembled from the novel tripodal host compound thioacetylhydrazine-functionalized tripillar[5]arene (TPSN) and tripodal guest compound 4-aminopyridine-functionalized trimesic amide (TAM). These host and guest compounds were designed based on the following strategy. First, the tripillar[5]arene structure was introduced into the TPSN to act as π−π, CH−π, and inclusion interaction sites. Second, a thioacetylhydrazine moiety was introduced into the host molecule to serve as a hydrogen bonding assembly site, as well as a coordination binding site for guests. Finally, the tripodal TAM was employed to construct multifunctional SOF-TPN with TPSN. As we expected, the tripodal TPSN and TAM assembled into supramolecular polymer networks and obtained a SOF-based stable organogel (SOF-TPN-G) with strong AIE simultaneously (Figure 1). Interestingly, by introducing Fe3+, Cu2+, Cr3+, Ag+, Tb3+, and Eu3+ cations into the organogel, respectively, a series of metallogels (SOF-Ms) with multicolor fluorescence was obtained. A novel and efficient eight-unit fluorescent sensor array based on these gels was successfully developed, which shows high sensitivity for Fe3+, Cu2+, Cr3+, Ag+, Tb3+, Eu3+, F−, CN−, HSO4−, His, Ser, and Cys. Among them, the detection for Fe3+, Cr3+, Tb3+, Eu3+, CN−, F−, and Ser reached an

Figure 1. Proposed assembly mechanism of SOF-TPN.

ultrasensitive level. These AIE organogel/metallogels can serve as novel multianalyte response materials.

■

EXPERIMENTAL SECTION

Materials. We purchased the metal ions (perchlorate salts) and anions (tetrabutyl ammonium salts) from Alfa Aesar. All amino acids were used as the L-style, which were purchased from Aladdin. The water used in the experiment was fresh double-distilled water, which was purified by experimental methods. The 1H NMR and 13C NMR spectra were recorded under the conditions of Varian Mercury 400 and Varian Inova 600 instruments. We recorded the MS (mass spectra) under the conditions of a Bruker Esquire 6000 MS instrument. The Rigaku RINT-2000 diffractometer was used to perform X-ray diffraction (XRD) analysis, which was equipped with graphite monochromated Cu Kα radiation (λ = 1.54073 Å). A fieldemission scanning electron microscopy (FE-SEM) system (JEOL, Model JSM-6701F) with an accelerating voltage of 8 kV was used to characterize the morphologies of xerogel. We performed and recorded the infrared (IR) spectra of compounds and complexes by using a Digilab FTS-3000 Fourier transform-infrared spectrophotometer. The uncorrected X-4 digital melting-point apparatus was used to measure the melting points of compounds. The spectrofluorophotometer (Shimadzu, Model RF-5301PC) was used to record the fluorescence spectra. Syntheses of TPSN. As shown in Scheme 1, 0.0246 g of 1,3,5benzenetricarbonyl trichloride (0.1 mmol) was added dropwise into the mixture of SPSH (0.32 mmol, 0.9104 g) and TEA (1 mL) in CH2Cl2. After reaction for 15 h at room temperature and removal of the solvent, the residue was washed by alcohol and water. Finally, the crude product was recrystallized in dichloromethane (DCM) and petroleum ether, obtaining the purified product TPSN (0.8781 g, 98% yield). The melting point was 105 °C. The 1H NMR spectrum was recorded at room temperature in DMSO-d6 (400 MHz) δ (ppm): 9.86 (s, 6 H), 8.31 (s, 3 H), 6.77 (m, 30 H), 3.63 (m, 117 H), 3.75 (s, 6 H), 1.83 (s, 6 H), 1.17 (m, 12 H). Mass spectrum (m/z): [M + H]+ Calcd C159H180N6O36S3: 2847.07, found 2847.06. General Procedures. 1H NMR Titration Experiment. First, the DMSO-d6 solution of TPSN (7.0 × 10−3 M) was obtained by 12000


Research Article

ACS Sustainable Chemistry & Engineering Scheme 1. Syntheses of TPSN

dissolving 10 mg of TPSN (3.5 × 10−6 mol) in 0.5 mL DMSO-d6. Then 1.0 equiv of TAM (0.1 M) was added into the above solution and mixed uniformly. Finally, the 1H NMR spectrum of them was recorded. Fluorescence Titration. Fluorescence Titration Based on Different Concentrations of Metal Ions. Different concentrations of metal ions, such as Fe3+, Cu2+, Cr3+, Ag+, Tb3+, and Eu3+, were added into the SOF-TPN-G (containing TPSN (8.5 mg) and TAM (1.5 mg) in a binary solution of dimethyl formamide (DMF) and H2O (0.2 mL, 1:1 (v/v))), resulting in a series of metal-ioncoordinated gels. Next, their fluorescent spectra at λex = 260 nm were recorded. Fluorescence Titration Based on Different Equivalent Anions and Amino Acids. A series of the SOF-Ms gels with different equivalents anions and amino acids (F−, CN−, HSO4−, Ser, His, and Cys) was prepared from SOF-Ms (5 mg) and different concentrations anion salts and amino acids in 0.2 mL DMF−H2O (V/V, 1:1) binary solution. Then, the fluorescence intensity of them was recorded at λex = 260 nm. Finally, the limits of detection (LODs) were calculated by the 3σ/m method.66 Adsorption Experiment. To begin with, 1 mg of xerogel of SOFTPN (6 × 10−7 mol) was added into 5.0 mL of water solution of Cu2+, Ag+, Fe3+, Cr3+, Tb3+, and Eu3+ (1 × 10−5 M), respectively. After stirring them for 10 min, the suspension was removed by centrifuging at 10 000 rpm for 5 min. Finally, the inductively coupled plasma (ICP) was used to assess the ingestion capacity of SOF-TPN for the aforementioned metal ions. Calculation of the Limit of Detection (LOD): 67 The following equations are used to determine the limit of detection (LOD):

S = A × 106

Here, Fi is the fluorescence emission intensity of SOF-TPN with different concentrations of metal ions at λem = 467 nm; F0 is 20 times the average fluorescence emission intensity of SOF-TPN at λem = 467 nm; A is the slope of equation of linear fitting; and B is the intercept of the equation of linear fitting. Calculation of the Adsorption Percentages. The adsorption percentage is calculated using the equation ij C × VR yzz adsorption percentage (%) = jjj1 − R zz × 100 j C I × VI z{ k

δ=

■

RESULTS AND DISCUSSION The novel tripodal host compound TPSN has been designed and synthesized according to Scheme 1. Meanwhile, the tripodal guest TAM was synthesized on the basis of previous methods (see Scheme S1 in the Supporting Information).68 We explored the self-assembly ability of TPSN and TAM in different solvents by using the method of “stable to inversion of a test tube”. We found that the TPSN or TAM itself could not form a gel based on SOFs in common solvents. However, under the host−guest interactions, the TPSN and TAM could assemble into a stable supramolecular organic framework gel (SOF-TPN-G), based on supramolecular polymer networks in a solution of DMF−H2O (1:1 (v/v)) (see Figure 2). Meanwhile, when the water content is 50%, the transition temperature from gel to sol (Tgel) of SOF-TPN-G (c = 7.5 mM) reached a limit at 50 °C (see Figure 3, as well as Table S1 in the Supporting Information). However, as shown in Figure S12 in the Supporting Information, when the water content is >50%, SOF-TPN-G would become unstable.

(1)

Σ(Fi − F0)2 N−1

LOD = K ×

δ S

(N = 20)

(K = 3)

(5)

where CR is the residual concentration of Fe3+, Cu2+, Cr3+, Ag+, Tb3+, and Eu3+; CI is the initial concentration of Fe3+, Cu2+, Cr3+, Ag+, Tb3+, and Eu3+; and VR = VI.

Equation of linear fitting:

y = Ax + B

(4)

(2)

(3) 12001


Research Article

ACS Sustainable Chemistry & Engineering

Then, the assembly machenism was also studied by 1H NMR titration of TPSN and TAM (Figure 4). After adding 1.0

Figure 2. Fluorescence spectra of TPSN, TAM, SOF-TPN (gel), and SOF-TPN (sol) in a solution of DMF−H2O (1:1 (v/v)). Insets show photographs of TPSN, TAM, SOF-TPN (gel), and SOF-TPN (sol) (left to right).

Figure 4. 1H NMR titration of TPSN (1.0 × 10−2 M) and TAM [(a) Free TPSN, (b) TPSN with TAM (1.0 equiv), and (c) Free TAM].

equiv TAM into the TPSN solution (DMSO-d6), the H3 (8.07 ppm) and H4 (8.57 ppm) on TAM all shows upfield shifts, simultaneously the Hf (6.74 ppm) on TPSN also show upfield shifts, which indicated that the pyridyl of TAM threaded into cavity of TPSN by interactions of CH-π and π−π (Figure 1).69 Meanwhile, in partial 1H NMR spectra of the mixture of TAM and TPSN with different concentration (Figure S13), the gradually increasing of TAM and TPSN concentrations induced upfield shifts of the Ha (8.97 ppm), Hd (6.74 ppm), H2 (8.97 ppm), H3 (8.07 ppm), and H4 (8.57 ppm) on mixture of TAM and TPSN, which also indicated that there are π−π and CH-π interactions in assembly process of TPSN and TAM.70 In addition, in Figure S14, after assembly of TPSN and TAN, the IR of CC and C−H on phenyl of TPSN all shows blue-shift (shifted from 1501 and 2928 cm−1 to 1515 and 2941 cm−1, respectively), also supporting the TAM and TPSN could assemble via π−π and CH−π interactions (Figure 1). At the same time, the assembly mechanism of TPSN and TAM was also investigated by 2D NOESY NMR experiment. In the 2D NOESY NMR spectrum (Figure S15 in the Supporting Information), there are three correlations for H3, H4 (on the TAM), and Hf (on cavity of the TPSN), which implied the pyridyl group of TAM and phenyl group of pillar[5]arene of TPSN established CH−π and π−π interactions. This result also supports the proposed inclusion process between TPSN and TAM. In other respects, the appearance of other correlations between Hf, Hg, and Hh were attributed to the CH−π interactions between phenyl groups of pillar[5]arene with methylene and methoxy groups.71 In addition, the XRD experiments (Figure S16 in the Supporting Information) were used to investigate the assembly of TPSN and TAM. In the XRD spectrum of the SOF-TPN-G xerogel, the d-spacing of 3.49 and 3.71 Å (2θ = 25.54° and 24.03°, respectively) indicated that there is π−π stacking in the assembly process of TPSN and TAM (recall Figure 1). Moreover, the d-spacing of 4.13 Å (2θ = 21.42°) (Figure S16)

Figure 3. Photographs and fluorescence emission intensity at λem = 467 nm of mixtures of TPSN and TAM in a DMF solution with different water contents.

Thereby, the DMF−H2O (1:1 (v/v)) is used as an ideal solvent for the formation of SOF-TPN-G. In the next section, the assembly mechanism of the SOFTPN-G (Figure 1) were carefully investigated by the fluorescence experiment, 1H NMR titration experiment, concentration-dependent 1H NMR, two-dimension NOESY, IR experiment, and so on. As shown in Figure 2, the TPSN emits very weak fluorescence at λem = 467 nm in a solution of DMF−H2O (1:1 (v/v)), while the TAM emits strong fluorescence at λem = 467 nm under the same conditions. However, after adding TAM into the hot solution of TPSN (DMF−H2O, 1:1 (v/v)), the fluorescence of the mixture at λem = 467 nm shows a decreasing trend, indicating the assembly of TPSN and TAM. In addition, after cooling the hot solution of TPSN and TAM to below the transition temperature from gel to sol of the SOF-TPN-G, the obtained gel shows dramatically enhanced fluorescence at λem = 467 nm (Figure 2), which indicated that the assembly and aggregation process of TPSN and TAM induced the AIE fluorescence. 12002


Research Article


Figure 5. Scanning electron microscopy (SEM) images: (a) TPSN; (b) TAM; and (c) xerogel of SOF-TPN-G.

(λex = 365 nm), the color of fluorescence emission changed from light-blue to yellow and pink, respectively, whereas the addition of other metal ions did not induce the changing of fluorescence. Thereby, SOF-TPN-G can give a fluorescence response to multiple metal ions, including Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+. The sensing sensitivity of SOF-TPN-G for the above-mentioned ions then was evaluated by the fluorescence titration experiments (see Figure 7, as well as

indicated that the three-dimensional (3D) layer structure existed in the SOF-TPN-G (see Figure 1). Moreover, hydrogen-bond interactions also were involved in the assembly process of SOF-TPN-G. In 1H NMR titration (Figure 4), when TAM was added into the TPSN solution (DMSO-d6), the Hb and Hc (9.92 ppm) on TPSN all show downfield shifts, indicating that there are hydrogen bonds between the thioacetylhydrazine group of adjacent molecules. Futhermore, in concentration-based 1H NMR of the mixture of TAM and TPSN (Figure S13 in the Supporting Information), the proton signals H1, Hb, and Hc (11.62 ppm) show downfield shifts, which also were attributed to the above-mentioned hydrogen bonds. Simultaneously, in IR analysis (Figure S14 in the Supporting Information), the assembly of TAM and TPSN caused the CO and N−H of TPSN to exhibit blue shifts (shifted to 1624 and 3435 cm−1, respectively), which also indicated the above-mentioned hydrogen bonds. In other words, the TPSN and TAM could assemble, resulting in supramolecular polymer networks, as well as form stable SOFTPN-G through the above-mentioned CH−π, π−π, and hydrogen bonds (Figure 1). Finally, the assembly mechanism was also supported by SEM. As shown in Figure 5, the powder of TPSN exists as an amorphous powder, and the powder of TAM exhibits rodlike structures. However, the xerogel of SOF-TPN-G shows a cross-linked network structure, which indicated that the TAM and TPSN can assembled into SOF-TPN. Then, the metal-ion response properties of SOF-TPN-G were primarily explored through adding a series of common metal ions, such as Ag+, Cu2+, Mg2+, Ca2+, Cd2+, Ba2+, Ni2+, Pb2+, Hg2+, Zn2+, Cr3+, Al3+, La3+, Fe3+, Tb3+, and Eu3+ into the SOF-TPN-G. After adding 2.0 equiv of Cr3+, Ag+, Fe3+, and Cu2+, the fluorescence of SOF-TPN-G was quenched (see Figure 6a); meanwhile, when 2.0 equiv of Tb3+ and Eu3+ were added into the SOF-TPN-G and irradiated by using a UV lamp

Figure 7. Fluorescence spectra of (a) SOF-TPN and SOF-TPN with Eu3+ and (b) SOF-TPN and SOF-TPN with Tb3+; fluorescence titration of (c) SOF-TPN for Eu3+ and (d) SOF-TPN for Tb3+.

Figures S17−S21 in the Supporting Information) and calculated by using the 3σ/m method;72 the LODs of SOFTPN for Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+ were 7.9 × 10−9, 6.6 × 10−9, 2.1 × 10−8, 6.8 × 10−10, 1.2 × 10−8, and 9.2 × 10−9 M, respectively (see Table 1), indicating that the SOF-TPN-G Table 1. LODs of SOF-TPN-G-Based Sensor Array for Multianalytes

Figure 6. Photographs of the SOF-TPN-G-based sensor array containing (a) cations, (b) amino acids, and (c) anions. 12003

entry

sensor

analyte

1 2 3 4 5 6 7 8 9 10 11 12 13

SOF-TPN-G SOF-TPN-G SOF-TPN-G SOF-TPN-G SOF-TPN-G SOF-TPN-G SOF-Fe SOF-Cu SOF-Eu SOF-Tb SOF-Fe SOF-Cu SOF-Eu

Fe3+ Cu2+ Cr3+ Ag+ Eu3+ Tb3+ F− HSO4− F− CN− Cys His Ser

LODs (M) 9.20 2.10 7.90 1.20 6.80 6.60 1.06 1.12 1.34 1.15 1.14 1.11 1.71

× × × × × × × × × × × × ×

10−9 10−8 10−9 10−8 10−10 10−9 10−8 10−8 10−8 10−8 10−8 10−8 10−8


Research Article

ACS Sustainable Chemistry & Engineering has high sensitivity for Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+. More importantly, compared with other reported chemosensors, the SOF-TPN-G shows more excellent sensitivity on the detection for Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+ (see Table S2 in the Supporting Information). Interestingly, by introducing Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+ into the SOF-TPN-G, respectively, a series of metallogels (SOF-Ms) was obtained, such as SOF-Cu, SOF-Eu, SOF-Fe, SOF-Tb, SOF-Ag, and SOF-Cr. The response properties of SOF-Ms for anions and amino acids were investigated by adding a series of anions (CN−, I−, F−, C, N3−, ClO4−, H2PO4−, AcO−, HSO4−, SCN−, Br−, OH−) and amino acids (Gly, Tyr, Arg, Val, Asp, Trp, Ser, Ala, Met, Thr, Glu, His, Asp, Pro, Leu, Ile, Phe, Gln, and Cys) into SOF-Ms. The result showed that the SOF-Fe, SOF-Tb, SOF-Eu, and SOF-Cu could selectively recognize F−, CN−, and HSO4−, respectively (Figure 6c); meanwhile, the SOF-Cu, SOF-Eu, and SOF-Fe could selectively detect His, Ser, and Cys, respectively (see Figure 6b). In addition, the detection sensitivities of SOF-Ms (SOF-Fe, SOF-Tb, SOF-Eu, and SOF-Cu) for anions (F−, HSO4−, CN−) and amino acids (Ser, His, and Cys) were evaluated using fluorescence titration experiments at room temperature (see Figure 8, as well as Figures S22−S29). The

99.34%, 99.95%, 98.30%, 98.40%, and 99.57%, respectively (see Table 2). Therefore, the SOF-TPN-G has outstanding Table 2. Absorbing Percentage of SOF-TPN for Metal Ions entry

metal ions

absorbing percentage (%)

1 2 3 4 5 6

Fe3+ Cu2+ Cr3+ Ag+ Tb3+ Eu3+

99.95 99.34 98.80 99.57 98.30 98.40

adsorption capacity for Cr3+, Cu2+, Fe3+, Eu3+, Tb3+, and Ag+ in aqueous solution. Furthermore, as shown in Table S3 in the Supporting Information, we compared the adsorption capacity of SOF-TPN-G with other materials for Cr3+, Cu2+, Fe3+, Eu3+, Tb3+, and Ag+, which shows that the SOF-TPN-G has more excellent adsorption ability for these metal ions than reported sensors. Then, the possible responsive mechanism of the SOF-TPNG for the above-mentioned metal ions, anions, and amino acids was carefully investigated. Taking Eu3+ as an example, after adding Eu3+ into the SOF-TPN-G, in IR, the N−H, CO, and C−S−C shifted from 3421, 1661, and 1043 cm−1 to 3393, 1598, and 1050 cm−1, respectively. This result indicated that N−H, CO, and C−S−C of SOF-TPN-G coordinated with Eu3+ (see Figure S30a in the Supporting Information). Meanwhile, the coordination-induced electron transfer between SOF-TPN-G and Eu3+ led to the fluorescence of SOFTPN-G changing. However, as shown in Figure S30a, when Ser was added into the SOF-Eu, the N−H, CO, and C−S− C recovered to 3421, 1060, and 1043 cm−1, indicating that Ser competitively coordinated with Eu3+ while, simultaneously, the fluorescence recovered (see Figure S31 in the Supporting Information). Similar tests were also applied to study the sensing mechanism of SOF-TPN-G for other metal ions (Fe3+, Tb3+, Cr3+, Ag+, and Cu2+) and SOF-Ms (SOF-Cu, SOF-Fe, SOFTb, and SOF-Eu) for anions (F−, CN−, and HSO4−) as well as other amino acids (His and Cys). As shown in Figures S30− S32 in the Supporting Information, when metal ions were added into the SOF-TPN-G, the C−S−C, N−H, and CO show corresponding shifts; meanwhile, the coordination process induced corresponding changes in fluorescence. However, after the addition of anions and amino acids into the SOF-Ms, the C−S−C recovered or showed other shifts. These results indicated that, because of the existence of the competitive coordination or corporate coordination, the high selective and sensitive recognition of SOF-TPN-G for metal ions and SOF-Ms for anions and amino acids were realized (Figures S33 and S34 in the Supporting Information). Moreover, the 1H NMR titration experiments were also used to investigate the possible coordination mechanism of the SOF-TPN-G with Ag+. As the concentration of Ag+ in DMSOd6 solution of SOF-TPN-G increased, the signals of Hd (2.86 ppm) and He (2.70 ppm) on CH2−S-CH2 show downfield shifts (see Figure S35 in the Supporting Information), suggesting that the Ag+ cation and the S atom of SOF-TPN coordinated (see Figure S36 in the Supporting Information).

Figure 8. Fluorescence spectra of (a) SOF-Tb and SOF-Tb with CN− and (b) SOF-Cu and SOF-Cu with His; fluorescence titration of (c) SOF-Tb for CN− and (d) SOF-Cu for His.

results show that these SOF-Ms have excellent sensitivity for recognition of F−, HSO4−, CN−, Ser, His, and Cys, respectively (see Table 1). More importantly, as shown in Figure 6, based on these gels, an eight-unit sensor array was successfully developed, which shows high sensitivity for Ag+, Cu2+, Fe3+, Cr3+, Tb3+, Eu3+ F−, CN−, HSO4−, His, Ser, and Cys. For application purposes, we assessed the ion removal property of SOF-TPN-G for Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+ in water, respectively. First, 1 mg of xerogel powder of SOF-TPN-G was added into 5.0 mL of an aqueous solution of Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+ (1 × 10−5 M), respectively. After they were stirred for 10 min, the suspension was removed using centrification. Then, the adsorption capacity of SOF-TPN for the above-mwntioned metal ions in the liquid supernatant were investigated by the inductively coupled plasma (ICP). The absorption percentages of SOFTPN-G for Cr3+, Cu2+, Fe3+, Eu3+, Tb3+, and Ag+ are 98.80%, 12004



■

CONCLUSIONS

■

ASSOCIATED CONTENT

■

REFERENCES

(1) Hong, Y.; Lam, Y. J. W.; Tang, B. Z. Aggregation-induced emission. Chem. Soc. Rev. 2011, 40, 5361. (2) Saltiel, A. R.; Kahn, C. R. Insulin signalling and the regulation of glucose and lipid metabolism. Nature 2001, 414, 799. (3) Hu, F.; Huang, Y.; Zhang, G.; Zhao, R.; Zhang, D. A highly selective fluorescence turn-on detection of hydrogen peroxide and Dglucose based on the aggregation/deaggregation of a modified tetraphenylethylene. Tetrahedron Lett. 2014, 55, 1471. (4) Perl, D. P.; Gajdusek, D. C.; Garruto, R. M.; Yanagihara, R. T.; Gibbs, C. J. Intraneuronal aluminum accumulation in amyotrophic lateral sclerosis and Parkinsonism-dementia of Guam. Science 1982, 217, 1053. (5) Feng, H. T.; Song, S.; Chen, Y. C.; Shen, C. H.; Zheng, Y. S. Selfassembled tetraphenylethylene macrocycle nanofibrous materials for the visual detection of copper(II) in water. J. Mater. Chem. C 2014, 2, 2353. (6) Wu, K. C.; Ku, P. J.; Lin, C. S.; Shih, H. T.; Wu, F. I.; Huang, M. J.; Lin, J. J.; Chen, I. C.; Cheng, C. H. The photophysical properties of dipyrenylbenzenes and their application as exceedingly efficient blue emitters for electroluminescent devices. Adv. Funct. Mater. 2008, 18, 67. (7) Huang, J.; Jiang, Y. B.; Yang, J.; Tang, R. L.; Xie, N.; Li, Q. Q.; Kwok, H. S.; Tang, B. Z.; Li, Z. Construction of efficient blue AIE emitters with triphenylamine and TPE moieties for non-doped OLEDs. J. Mater. Chem. C 2014, 2, 2028. (8) Wang, J.; Mei, J.; Hu, R.; Sun, J. Z.; Qin, A.; Tang, B. Z. Click synthesis, aggregation-induced emission, E/Z isomerization, selforganization, and multiple chromisms of pure stereoisomers of a tetraphenylethene-cored luminogen. J. Am. Chem. Soc. 2012, 134, 9956. (9) Misra, R.; Jadhav, T.; Dhokale, B.; Mobin, S. M. Reversible mechanochromism and enhanced AIE in tetraphenylethene substituted phenanthroimidazoles. Chem. Commun. 2014, 50, 9076. (10) Leung, C. W. T.; Hong, Y.; Chen, S. J.; Zhao, E. G.; Lam, J. W. Y.; Tang, B. Z. A photostable AIE luminogen for specific mitochondrial imaging and tracking. J. Am. Chem. Soc. 2013, 135, 62. (11) Mei, J.; Leung, N. L. C.; Kwok, R. T. K.; Lam, J. W. Y.; Tang, B. Z. Aggregation-induced emission: together we shine, united we soar. Chem. Rev. 2015, 115, 11718. (12) Zhang, C. J.; Yao, X. Y.; Wang, J.; Ma, X. Tunable emission of a tetraphenylethylene copolymer via polymer matrix assisted and aggregation-induced emission. Polym. Chem. 2017, 8, 4835. (13) Wu, J.; Xu, Y.; Li, D. F.; Ma, X.; Tian, H. End-to-end assembly and disassembly of gold nanorods based on photo-responsive host− guest interaction. Chem. Commun. 2017, 53, 4577. (14) Zhang, K. D.; Tian, J.; Hanifi, D.; Zhang, Y. B.; Sue, A. C. H.; Zhou, T. Y.; Zhang, L.; Zhao, X.; Liu, Y.; Li, Z. T. Toward a Singlelayer two-dimensional honeycomb supramolecular organic framework in water. J. Am. Chem. Soc. 2013, 135, 17913. (15) Lü, J.; Perez-Krap, C.; Suyetin, M.; Alsmail, N. H.; Yan, Y.; Yang, S. H.; Lewis, W.; Bichoutskaia, E.; Tang, C. C.; Blake, A. J.; Cao, R.; Schröder, M. A robust binary supramolecular organic framework (SOF) with high CO2 adsorption and selectivity. J. Am. Chem. Soc. 2014, 136, 12828. (16) Li, Y. W.; Dong, Y. B.; Miao, X. R.; Ren, Y. L.; Zhang, B. L.; Wang, P. P.; Yu, Y.; Li, B.; Isaacs, L.; Cao, L. P. Shape-controllable and fluorescent supramolecular organic frameworks through aqueous host-guest complexation. Angew. Chem., Int. Ed. 2018, 57, 729. (17) Tan, L. L.; Li, H. W.; Tao, Y. C.; Zhang, S. X. A.; Wang, B.; Yang, Y. W. Pillar[5]arene-based supramolecular organic frameworks for highly selective CO2-capture at ambient conditions. Adv. Mater. 2014, 26, 7027. (18) Patil, R. S.; Banerjee, D.; Zhang, C.; Thallapally, P. K.; Atwood, J. L. Selective CO2 adsorption in a supramolecular organic framework. Angew. Chem., Int. Ed. 2016, 55, 4523. (19) Patil, R. S.; Banerjee, D.; Zhang, C.; Thallapally, P. K.; Atwood, J. L. Selective CO2 adsorption in a supramolecular organic framework. Angew. Chem. 2016, 128, 4599.

In conclusion, we successfully constructed a supramolecular organic framework gel (SOF-TPN-G) from a novel triodal pillar[5]arene-based supramolecular polymer networks. Interestingly, the SOF-TPN-G shows strong AIE; meanwhile, a series of metallogels (SOF-Ms) with multicolor fluorescence was constructed by introducing Fe3+, Cu2+, Cr3+, Ag+, Tb3+, and Eu3+ into the organogel (SOF-TPN-G). Moreover, an eight-unit fluorescent sensor array based on these gels was successfully developed, which shows high sensitivity fluorescent response for Fe3+, Cu2+, Cr3+, Ag+, Tb3+, Eu3+, F−, CN−, HSO4−, His, Ser, and Cys. The LODs of the sensor array for the above-mentioned multianalytes range from 1.20 × 10−8 M to 6.80 × 10−10 M. Among them, the detection for Fe3+, Cr3+, Tb3+, Eu3+, CN−, F−, and Ser reached an ultrasensitive level. More importantly, the xerogel of SOF-TPN-G could excellently adsorb Cr3+, Eu3+, Cu2+, Tb3+, Fe3+, and Ag+ from their aqueous solution, the absorption percentages for them are 98.80%, 98.40%, 99.34%, 98.30%, 99.95%, and 99.57%, respectively. These AIE organogel/metallogels are novel fluorescent stimuli-responsive materials. In addition, the approach of constructing AIE SOF materials through supramolecular polymer networks based on tripodal pillar[5]arene may supply new idea regarding the design of novel multifunctional AIE fluorescent materials.

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acssuschemeng.9b00452. (1) 1H NMR and MS spectra of SZ, SP5, SPSE, SPSJ, and TAM; (2) IR spectra of correlative compounds (TPSN and xerogel); (3) 1H NMR NOESY spectra of correlative compounds (the mixture of TPSN and TAM); (4) powder XRD spectra of TPSN and xerogel; (5) fluorescence spectra; (6) fluorescence titration; (7) photograph of the linear range; (8) 1H NMR titration of SOF-TPN for Ag+; (9) a series of literature about the uptake and LOD (mol/L) of metal ions (Ag+, Cu2+, Fe3+, Cr3+, Tb3+, and Eu3+) (PDF)

■

Research Article

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected] (J. Liu). *E-mail: [email protected] (T.-B. Wei). *E-mail: [email protected] (Q. Lin). ORCID

Qi Lin: 0000-0002-3786-3593 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (NSFC) (Nos. 21574104, 21662031, and 21661028) and the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (No. IRT1177). 12005


Research Article


molecular machines, and supramolecular catalysis. Chem. Rev. 2017, 117, 4900. (39) Rachuri, Y.; Parmar, B.; Suresh, E. Three-dimensional Co(II)/ Cd(II) metal-organic frameworks: luminescent Cd-MOF for detection and adsorption of 2, 4, 6-trinitrophenol in the aqueous phase. Cryst. Growth Des. 2018, 18, 3062. (40) Ju, B.; Wang, Y.; Zhang, Y. M.; Zhang, T.; Liu, Z. H.; Li, M. J.; Zhang, S. X.-A. Photostable and low-toxic yellow-green carbon dots for highly selective detection of explosive 2, 4, 6-trinitrophenol based on the dual electron transfer mechanism. ACS Appl. Mater. Interfaces 2018, 10, 13040. (41) Wang, M.; Ye, H. B.; You, L.; Chen, X. Y. A supramolecular sensor array using lanthanide-doped nanoparticles for sensitive detection of glyphosate and proteins. ACS Appl. Mater. Interfaces 2016, 8, 574. (42) Bojanowski, N. M.; Hainer, F.; Bender, M.; Seehafer, K.; Bunz, U. H. F. An optical sensor array discriminates syrups and honeys. Chem. - Eur. J. 2018, 24, 4255. (43) Qu, W. J.; Yan, G. T.; Ma, X. L.; Wei, T. B.; Lin, Q.; Yao, H.; Zhang, Y. M. Cascade recognition” of Cu2+ and H2PO4− with high sensitivity and selectivity in aqueous media based on the effect of ESIPT. Sens. Actuators, B 2017, 242, 849. (44) Rankin, J. M.; Zhang, Q. F.; LaGasse, M. K.; Zhang, Y. A.; Askim, J. R.; Suslick, K. S. Solvatochromic sensor array for the identification of common organic solvents. Analyst 2015, 140, 2613. (45) Askim, J. R.; Suslick, K. S. Hand-held reader for colorimetric sensor arrays. Anal. Chem. 2015, 87, 7810. (46) Zheng, H.; Qian, Z. H.; Xu, L.; Yuan, F. F.; Lan, L. D.; Xu, J. G. Switching the recognition preference of rhodamine B spirolactam by replacing one atom: design of rhodamine B thiohydrazide for recognition of Hg(II) in aqueous solution. Org. Lett. 2006, 8, 859. (47) Ravikumar, A.; Panneerselvam, P.; Morad, N. Metal− polydopamine framework as an effective fluorescent quencher for highly sensitive detection of Hg(II) and Ag(I) ions through exonuclease III activity. ACS Appl. Mater. Interfaces 2018, 10, 20550. (48) Huang, W.; Xie, Z. Y.; Deng, Y. Q.; He, Y. 3,3′,5,5′tetramethylbenzidine-based quadruple-channel visual colorimetric sensor array for highly sensitive discrimination of serum antioxidants. Sens. Actuators, B 2018, 254, 1057. (49) He, W. W.; Luo, L.; Liu, Q. Y.; Chen, Z. B. Colorimetric sensor array for discrimination of heavy metal ions in aqueous solution based on three kinds of thiols as receptors. Anal. Chem. 2018, 90, 4770. (50) Svechkarev, D.; Sadykov, M. R.; Bayles, K. W.; Mohs, A. M. Ratiometric fluorescent sensor array as a versatile tool for bacterial pathogen identification and analysis. ACS Sens. 2018, 3, 700. (51) Zhu, Q. J.; Xiong, W.; Gong, Y. J.; Zheng, Y. X.; Che, Y. K.; Zhao, J. C. Discrimination of five classes of explosives by a fluorescence array sensor composed of two tricarbazole-nanostructures. Anal. Chem. 2017, 89, 11908. (52) Sener, G.; Uzun, L.; Denizli, A. Colorimetric sensor array based on gold nanoparticles and amino acids for identification of toxic metal ions in water. ACS Appl. Mater. Interfaces 2014, 6, 18395. (53) Dugandžić, V.; Kupfer, S.; Jahn, M.; Henkel, T.; Weber, K.; Cialla-May, D.; Popp, J. A SERS-based molecular sensor for selective detection and quantification of copper(II) ions. Sens. Actuators, B 2019, 279, 230. (54) De, M.; Rana, S.; Akpinar, H.; Miranda, O. R.; Arvizo, R. R.; Bunz, U. H. F.; Rotello, V. M. Sensing of proteins in human serum using conjugates of nanoparticles and green fluorescent protein. Nat. Chem. 2009, 1, 461. (55) Pei, H.; Li, J.; Lv, M.; Wang, J.; Gao, J.; Lu, J.; Li, Y.; Huang, Q.; Hu, J.; Fan, C. A graphene-based sensor array for high-precision and adaptive target identification with ensemble aptamers. J. Am. Chem. Soc. 2012, 134, 13843. (56) Pezzato, C.; Lee, B.; Severin, K.; Prins, L. J. Pattern-based sensing of nucleotides with functionalized gold nanoparticles. Chem. Commun. 2013, 49, 469.

(20) Shanmugaraju, S.; Dabadie, C.; Byrne, K.; Savyasachi, A. J.; Umadevi, D.; Schmitt, W.; Kitchen, J. A.; Gunnlaugsson, T. A supramolecular Tröger’s base derived coordination zinc polymer for fluorescent sensing of phenolic-nitroaromatic explosives in water. Chem. Sci. 2017, 8, 1535. (21) Ogoshi, T.; Ueshima, N.; Yamagishi, T. An amphiphilic pillar[5]arene as efficient and substrate-selective phase-transfer catalyst. Org. Lett. 2013, 15, 3742. (22) Patil, R. S.; Zhang, C.; Barnes, C. L.; Atwood, J. L. Construction of supramolecular organic frameworks based on noria and bipyridine type spacers. Cryst. Growth Des. 2017, 17, 7. (23) Xu, S. Q.; Zhang, X.; Nie, C. B.; Pang, Z. F.; Xu, X. N.; Zhao, X. The construction of a two-dimensional supramolecular organic framework with parallelogram pores and stepwise fluorescence enhancement. Chem. Commun. 2015, 51, 16417. (24) Ogoshi, T.; Yamagishi, T.; Nakamoto, Y. Pillar-shaped macrocyclic hosts pillar[n]arenes: new key players for supramolecular chemistry. Chem. Rev. 2016, 116, 7937. (25) Yang, L. l.; Tan, X. X.; Wang, Z. Q.; Zhang, X. Supramolecular polymers: historical development, preparation, characterization, and functions. Chem. Rev. 2015, 115, 7196. (26) Yang, K.; Pei, Y.; Wen, J.; Pei, Z. Recent advances in pillar[n]arenes: synthesis and applications based on host-guest interactions. Chem. Commun. 2016, 52, 9316. (27) Yao, J. B.; Wu, W. H.; Liang, W. T.; Feng, Y. J.; Zhou, D. Y.; Chruma, J. J.; Fukuhara, G.; Mori, T.; Inoue, Y.; Yang, C. Temperature-driven planar chirality switching of a pillar[5]arenebased molecular universal joint. Angew. Chem., Int. Ed. 2017, 56, 6869. (28) Wu, X. W.; Zhang, Y.; Lu, Y. C.; Pang, S.; Yang, K.; Tian, Z.; Pei, Y. X.; Qu, Y. Q.; Wang, F.; Pei, Z. C. Synergistic and targeted drug delivery based on nano-CeO2 capped with galactose functionalized pillar[5]arene via host-guest interactions. J. Mater. Chem. B 2017, 5, 3483. (29) Shangguan, L. Q.; Xing, H.; Mondal, J. H.; Shi, B. B. Novel rare earth fluorescent supramolecular polymeric assemblies constructed by orthogonal pillar[5]arene-based molecular recognition, Eu(III)coordination and π-π donor-acceptor interactions. Chem. Commun. 2017, 53, 889. (30) Yu, G. C.; Jie, K. C.; Huang, F. H. Supramolecular amphiphiles based on host-guest molecular recognition motifs. Chem. Rev. 2015, 115, 7240. (31) Qu, D. H.; Wang, Q. C.; Zhang, Q. W.; Ma, X.; Tian, H. Photoresponsive host-guest functional systems. Chem. Rev. 2015, 115, 7543. (c) McConnell, A. J.; Wood, C. S.; Neelakandan, P. P.; Nitschke, J. R. Stimuli-responsive metal-ligand assemblies. Chem. Rev. 2015, 115, 7729. (32) Chi, X. D.; Ji, X. F.; Xia, D. Y.; Huang, F. H. A dual-responsive supra-amphiphilic polypseudorotaxane constructed from a watersoluble pillar[7]arene and an azobenzene-containing random copolymer. J. Am. Chem. Soc. 2015, 137, 1440. (33) Wei, T. B.; Chen, J. F.; Cheng, X. B.; Li, H.; Han, B. B.; Yao, H.; Zhang, Y. M.; Lin, Q. Construction of stimuli-responsive supramolecular gel via bispillar[5]arene-based multiple interactions. Polym. Chem. 2017, 8, 2005. (34) Xue, M.; Yang, Y.; Chi, X. C.; Yan, X. Z.; Huang, F. H. Development of pseudorotaxanes and rotaxanes: from synthesis to stimuli-responsive motions to applications. Chem. Rev. 2015, 115, 7398. (35) Carter, K. P.; Young, A. M.; Palmer, A. E. Fluorescent sensors for measuring metal ions in living systems. Chem. Rev. 2014, 114, 4564. (36) Paulsen, C. E.; Carroll, K. S. Cysteine-mediated redox signaling: chemistry, biology, and tools for discovery. Chem. Rev. 2013, 113, 4633. (37) Krieg, E.; Bastings, M. M. C.; Besenius, P.; Rybtchinski, B. Supramolecular polymers in aqueous media. Chem. Rev. 2016, 116, 2414. (38) Zhang, D. W.; Martinez, A.; Dutasta, J. P. Emergence of hemicryptophanes: from synthesis to applications for recognition, 12006


Research Article

ACS Sustainable Chemistry & Engineering (57) Liu, Y. L.; Minami, T.; Nishiyabu, R.; Wang, Z., Jr.; Anzenbacher, P. Sensing of carboxylate drugs in urine by a supramolecular sensor array. J. Am. Chem. Soc. 2013, 135, 7705. (58) Lin, Q.; Lu, T. T.; Zhu, X.; Wei, T. B.; Li, H.; Zhang, Y. M. Rationally introduce multi-competitive binding interactions in supramolecular gels: a simple and efficient approach to develop multi-analyte sensor array. Chem. Sci. 2016, 7, 5341. (59) Lin, Q.; Zhong, K. P.; Zhu, J. H.; Ding, L.; Su, J. X.; Yao, H.; Wei, T. B.; Zhang, Y. M. Iodine controlled pillar[5]arene-based multiresponsive supramolecular polymer for fluorescence detection of cyanide, mercury, and cysteine. Macromolecules 2017, 50, 7863. (60) Lin, Q.; Lu, T. T.; Zhu, X.; Sun, B.; Yang, Q. P.; Wei, T. B.; Zhang, Y. M. A novel supramolecular metallogel-based highresolution anion sensor array. Chem. Commun. 2015, 51, 1635. (61) Lin, Q.; Sun, B.; Yang, Q. P.; Fu, Y. P.; Zhu, X.; Zhang, Y. M.; Wei, T. B. A novel strategy for the design of smart supramolecular gels: controlling stimuli-response properties through competitive coordination of two different metal ions. Chem. Commun. 2014, 50, 10669. (62) Chen, J. F.; Lin, Q.; Zhang, Y. M.; Yao, H.; Wei, T. B. Pillararene-based fluorescent chemosensors: recent advances and perspectives. Chem. Commun. 2017, 53, 13296. (63) Lin, Q.; Fan, Y. Q.; Mao, P. P.; Liu, L.; Liu, J.; Zhang, Y. M.; Yao, H.; Wei, T. B. Pillar[5]arene-based supramolecular organic framework with multi-guest detection and recyclable separation properties. Chem. - Eur. J. 2018, 24, 777. (64) Lin, Q.; Fan, Y. Q.; Gong, G. F.; Mao, P. P.; Wang, J.; Guan, X. W.; Liu, J.; Zhang, Y. M.; Yao, H.; Wei, T. B. Ultrasensitive detection of formaldehyde in gas and solutions by a catalyst preplaced sensor based on a pillar[5]arene derivative. ACS Sustainable Chem. Eng. 2018, 6, 8775. (65) Wei, T. B.; Chen, J. F.; Cheng, X. B.; Li, H.; Han, B. B.; Zhang, Y. M.; Yao, H.; Lin, Q. A novel functionalized pillar[5]arene-based selective amino acid sensor for L-tryptophan. Org. Chem. Front. 2017, 4, 210. (66) Sun, X.; Wang, Y. W.; Peng, Y. A selective and ratiometric bifunctional fluorescent probe for Al3+ ion and proton. Org. Lett. 2012, 14, 3420. (67) Hua, Y. X.; Shao, Y. L.; Wang, Y. W.; Peng, Y. A series of fluorescent and colorimetric chemodosimeters for selective recognition of cyanide based on the FRET mechanism. J. Org. Chem. 2017, 82, 6259. (68) Luo, X. Z.; Jia, X. J.; Deng, J. H.; Zhong, J. L.; Liu, H. J.; Wang, K. J.; Zhong, D. C. A microporous hydrogen-bonded organic framework: exceptional stability and highly selective adsorption of gas and liquid. J. Am. Chem. Soc. 2013, 135, 11684. (69) Babu, S. S.; Praveen, V. K.; Ajayaghosh, A. Functional πgelators and their applications. Chem. Rev. 2014, 114, 1973. (70) Shen, Z. C.; Jiang, Y. Q.; Wang, T. Y.; Liu, M. H. Symmetry breaking in the supramolecular gels of an achiral gelator exclusively driven by π−π stacking. J. Am. Chem. Soc. 2015, 137, 16109. (71) Leung, S. Y. L.; Evariste, S.; Lescop, C.; Hissler, M.; Yam, V. W. W. Supramolecular assembly of a phosphole-based moiety into nanostructures dictated by alkynylplatinum(II) terpyridine complexes through non-covalent Pt···Pt and π−π stacking interactions: synthesis, characterization, photophysics and self-assembly behaviors. Chem. Sci. 2017, 8, 4264. (72) Analytical Methods Committee. Recommendations for the definition, estimation and use of the detection limit. Analyst 1987, 112, 199

12007


Aggregation-Induced Emission Supramolecular Organic Framework

Recommend Documents