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

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 Fe 3+ , Cu 2+ , Cr 3+ , Ag + , Tb 3+ , and Eu 3+ 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

Pillararenes Trimer for Self-Assembly

“…For example, PT3 (Scheme 1) was synthesized by rationally connecting three units of pillararenes (X4, Scheme 3) together via the reaction between 1,3,5-benzenetricarbonyl trichloride and dihydrazide moieties in dichloromethane for 12 h [21]. By using very similar synthesis procedure but different pillar [5]arenes precursors such as X9 (Scheme 3), 1,3,5-benzenetricarbonyl trichloride can also act as the core structure in another trimer-PT7 (Scheme 1) [24]. In addition, the 1,3,5-benzenetricarbonyl trichloride could perform an esterification in chloroform with three equivalent of pillararenes precursor X5 (Scheme 3) to obtain another star-shaped trimer, PT4 (Scheme 1) [19].…”

“…. π and π-π stacking interactions could exhibit fluorescent response for multiple metal cations such as Fe 3+ , Cu 2+ , Cr 3+ , Ag + , Tb 3+ , and Eu 3+ [24].…”

“…Due to the coordination between dihydrazide moieties on PT3 and metal cations such as Hg 2+ , the intermolecular hydrogen bonds are affected, leading to quench of AIE and the disassociation of supramolecular polymers (Figure 6). Furthermore, the AIE supramolecular organic framework gel prepared by thioacetylhydrazine-bearing pillar [5]arenes trimer PT7 (Scheme 1) and 4-aminopyridine-functionalized trimeric amide G6 (Scheme 2) via hydrogen bonding, C-H … π and π-π stacking interactions could exhibit fluorescent response for multiple metal cations such as Fe 3+ , Cu 2+ , Cr 3+ , Ag + , Tb 3+ , and Eu 3+ [24]. Except for response to metal cations, pillararenes trimer-based material can also be responsive to anion and solvent molecules.…”

“…Due to the possession of stronger binding constants between metal cations and specialized anions, those metal ligated materials could further carry out selective fluorescence "turn-on" ultrasensitive detection towards anions such as CN − and H 2 PO 4 − , giving the limits of detection as 2.12 × 10 −9 and 1.78 × 10 −9 mol L −1 , respectively [23]. Due to the capacity of multiple responsiveness to metal cations, anions, and amino acid, the PT7-based AIE supramolecular organic framework gels and metallogels could behave as a multi-unit sensor array for Fe 3+ , Cu 2+ , Cr 3+ , Ag + , Tb 3+ , Eu 3+ , F − , CN − , HSO 4 − , histidine (His), serine (Ser), and cysteine (Cys) [24] with the limits of detection ranging from 1.20 × 10 −8 to 6.80 × 10 −10 mol L −1 . Particularly, the detection for Fe 3+ , Cr 3+ , Tb 3+ , Eu 3+ , F − , CN − , and serine could achieve an ultrasensitive level.…”

“…(4) alternative building blocks integrated with multi-subunits of pillararenes such as pillararenes tetramers [32][33][34][35][36][37] and other significant pillararenes oligomers [38,39] should be designed based on the researches of pillararenes trimers, as well as applied for recognizing multiple guests and fabricating assembled materials. (5) except for synthesizing novel pillararenes trimers, preparing trimeric guest molecules [40][41][42][43] is another alternative method to build planar assembled networks [19,24]. It is expected that future researches in the field of pillararenes trimers-based supramolecular assemblies will achieve to a new level in not only fundamental studies but also in practical applications in our lives.…”