6 research outputs found
A Diheteroatom Fluoroalkylation Reagent for Preparation of S- and NâContaining Fluoroalkyl Compounds and Sulfonic Acid Polymer
The
first stable diheteroatom fluoroalkylation reagent, 2-((2-azido-1-chloro-1,2,2-trifluoroÂethyl)Âthio)Âpyrimidine
(ACTP), has been prepared by a novel method. By using this reagent,
various fluorinated thioethers and sulfones have been successfully
prepared. The dearylation and dearylationâoxidaÂtion 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
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
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 âŒ0.24, 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
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 âŒ0.24, 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
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 âtwo-dimensional
self-assembly polymerization (2DSP)â 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
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 â1D
to 2Dâ 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, ÏâÏ
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