6 research outputs found

    A Diheteroatom Fluoroalkylation Reagent for Preparation of S- and N‑Containing Fluoroalkyl Compounds and Sulfonic Acid Polymer

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    The first stable diheteroatom fluoroalkylation reagent, 2-((2-azido-1-chloro-1,2,2-trifluoro­ethyl)­thio)­pyrimidine (ACTP), has been prepared by a novel method. By using this reagent, various fluorinated thioethers and sulfones have been successfully prepared. The dearylation and dearylation–oxida­tion of fluoroalkyl 2-pyrimidyl sulfone in one-pot reaction were investigated systematically, and the results demonstrated that both fluoroalkyl sulfinates and sulfonates could be obtained in high yields. In addition, ACTP proved to be useful for the preparation of a fluorinated sulfonic acid proton-exchange membrane

    Facile and Highly Efficient Strategy for Synthesis of Functional Polyesters via Tetramethyl Guanidine Promoted Polyesterification at Room Temperature

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    A facile and highly efficient strategy for the synthesis of functional polyesters from 10-undecenoic acid, which is abundantly available and derived from ricin oil, has been successfully achieved using 1,1,3,3-tetramethyl guanidine (TMG) as a promoter at room temperature. The experimental results indicate that high molecular weight polyesters have been obtained and a variety of functional groups, such as alkenyl, alkynyl, nitro, epoxy, hydroxyl, and bromoisobutyrate, can be incorporated as pendant groups. The structures of the obtained polymers were demonstrated by <sup>1</sup>H and <sup>13</sup>C NMR spectroscopy and their thermal properties were studied by DSC and TGA

    Novel Reversible Mechanochromic Elastomer with High Sensitivity: Bond Scission and Bending-Induced Multicolor Switching

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    Although the rational designed mechanochromic polymer (MCP) materials have evoked major interest and experienced significant progress recently, it is still a great challenge to develop a facile and effective strategy for preparation of reversible broad-spectrum MCPs with a combination of wide-range color switch ability and high sensitivity, which thus make it possible to mimic gorgeous color change as in nature. Herein, we designed and synthesized a novel rhodamine-based mechanochromic elastomer. Our results demonstrated that the elastomer exhibited very promising and unique properties. Three primary fluorescence colors were presented during continuous uniaxial extension and relaxing process, and reversible broad-spectrum fluorescence color change could be achieved consequently. The fluorescence quantum yield of the opened zwitterion of this new mechanophore was as high as 0.67. In addition, the elastomer showed very high sensitivity to stress with a detectable activation strain of ∌0.24, which was much smaller than those reported in the previous literature reports. Meantime, the easy-to-obtain material, facile preparation, and good mechanical property also made it suitable for potential practical applications

    Novel Reversible Mechanochromic Elastomer with High Sensitivity: Bond Scission and Bending-Induced Multicolor Switching

    No full text
    Although the rational designed mechanochromic polymer (MCP) materials have evoked major interest and experienced significant progress recently, it is still a great challenge to develop a facile and effective strategy for preparation of reversible broad-spectrum MCPs with a combination of wide-range color switch ability and high sensitivity, which thus make it possible to mimic gorgeous color change as in nature. Herein, we designed and synthesized a novel rhodamine-based mechanochromic elastomer. Our results demonstrated that the elastomer exhibited very promising and unique properties. Three primary fluorescence colors were presented during continuous uniaxial extension and relaxing process, and reversible broad-spectrum fluorescence color change could be achieved consequently. The fluorescence quantum yield of the opened zwitterion of this new mechanophore was as high as 0.67. In addition, the elastomer showed very high sensitivity to stress with a detectable activation strain of ∌0.24, which was much smaller than those reported in the previous literature reports. Meantime, the easy-to-obtain material, facile preparation, and good mechanical property also made it suitable for potential practical applications

    Preparation of Covalent Pseudo-Two-Dimensional Polymers in Water by Free Radical Polymerization

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    Two-dimensional (2D) polymer has attracted considerable attention due to its excellent properties. Although a number of 2D polymers have been reported, preparation of free-standing single-layer 2D polymers in solution is still a big challenge. Here we report a facile and highly efficient strategy for synthesis of free-standing single-layer covalent pseudo-2D polymers via free radical polymerization in water on a large scale. The strategy designated as “two-dimensional self-assembly polymerization (2DSP)” includes formation of supramolecular 2D nanosheets by self-assembly of bola-amphiphilic monomer that bearing two maleic acid moieties and transformation of supramolecular 2D nanosheets to covalent pseudo-2D polymers by copolymerization with vinyl monomers. We find that the counterion of the bola-amphiphile has a significant influence on formation of single-layer supramolecular 2D nanosheets, and the formation of 2D polymer sheets is highly related to the vinyl monomers. The unique 2D polymer sheets were used to prepare hydrogels with excellent mechanical properties

    From 1D Polymers to 2D Polymers: Preparation of Free-Standing Single-Monomer-Thick Two-Dimensional Conjugated Polymers in Water

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    Recently, investigation on two-dimensional (2D) organic polymers has made great progress, and conjugated 2D polymers already play a dynamic role in both academic and practical applications. However, a convenient, noninterfacial approach to obtain single-layer 2D polymers in solution, especially in aqueous media, remains challenging. Herein, we present a facile, highly efficient, and versatile “1D to 2D” strategy for preparation of free-standing single-monomer-thick conjugated 2D polymers in water without any aid. The 2D structure was achieved by taking advantage of the side-by-side self-assembly of a rigid amphiphilic 1D polymer and following topochemical photopolymerization in water. The spontaneous formation of single-layer polymer sheets was driven by synergetic association of the hydrophobic interactions, π–π stacking interactions, and electrostatic repulsion. Both the supramolecular sheets and the covalent sheets were confirmed by spectroscopic analyses and electron microscope techniques. Moreover, in comparison of the supramolecular 2D polymer, the covalent 2D polymer sheets exhibited not only higher mechanical strength but also higher conductivity, which can be ascribed to the conjugated network within the covalent 2D polymer sheets
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