The biobased renewable monomer 2,5-diformylfuran is polymerised using various N-heterocyclic carbene(NHC)catalysts in dimethyl sulfoxide(DMSO)affording a low molar mass polymer.It is shown that catalyst structure as w...The biobased renewable monomer 2,5-diformylfuran is polymerised using various N-heterocyclic carbene(NHC)catalysts in dimethyl sulfoxide(DMSO)affording a low molar mass polymer.It is shown that catalyst structure as well as the temperature and time the polymerization is running have a noticeable effect on its molar mass.The obtained material is characterized by nuclear magnetic resonance(NMR),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).An attempt at chain extension with diamine leads to precipitation of the polymer.This new biobased polymer material might be useful as a sustainable resin.展开更多
Macrocycles possess potential applications in supramolecular chemistry and biosystems. Thus development of new kinds of macrocycles is of significance. Herein, novel macrocycles containing Se-Se/Se-S bonds were synthe...Macrocycles possess potential applications in supramolecular chemistry and biosystems. Thus development of new kinds of macrocycles is of significance. Herein, novel macrocycles containing Se-Se/Se-S bonds were synthesized via transformation between selenium related dynamic covalent bonds. A monomer containing two ebselen moieties was synthesized (M1). The Se-N bonds in M1 were reduced by dithiothreitol, forming Se-S linked dimer (D1). To realize the transformation from Se-S bonds to Se-Se bonds, guest molecules were added as template, triggering the formation of Se-Se linked dimer (D2). The formation of these two new kinds of macrocycles was determined by H-1 NMR and Se-77 NMR, and the necessity of guest molecules was also confirmed. The introduction of ebselen moieties and Se-S bonds or Se-Se bonds into macrocycles may endow it with new responsiveness and bioactivities, as well as new types of host-guest chemistry.展开更多
We have described the synthesis of a series of poly(aryl ether) dendrimers with telluride in the core and oligo(ethylene oxide) chains at the pe- riphery which act as glutathione peroxidase (GPx) mimics. These series ...We have described the synthesis of a series of poly(aryl ether) dendrimers with telluride in the core and oligo(ethylene oxide) chains at the pe- riphery which act as glutathione peroxidase (GPx) mimics. These series of compounds were well characterized by H-NMR, 1 13C-NMR and ESI-MS. Using different ROOH (H2O2, cumene hydroperoxide) for testing the antioxidizing properties of these com- pounds, we have found that from generation 0 to 2, the activity of the dendritic GPx mimics first de- creased and then increased. This can be explained on the basis of a greater steric hindrance, going from generation 0 to 1, and stronger binding interactions going from generation 1 to 2. In other words, there exists a balance between binding interactions and steric hindrance that may optimize the GPx activity.展开更多
基金This research was funded by Research Foundation-Flanders,grant number G0D5416N。
文摘The biobased renewable monomer 2,5-diformylfuran is polymerised using various N-heterocyclic carbene(NHC)catalysts in dimethyl sulfoxide(DMSO)affording a low molar mass polymer.It is shown that catalyst structure as well as the temperature and time the polymerization is running have a noticeable effect on its molar mass.The obtained material is characterized by nuclear magnetic resonance(NMR),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).An attempt at chain extension with diamine leads to precipitation of the polymer.This new biobased polymer material might be useful as a sustainable resin.
基金supported by the National Science Foundation for Distinguished Young Scholars(21425416)the National Basic Research Program of China(2013CB834502)+1 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(21421064)the National Natural Science Foundation of China(91427301)
文摘Macrocycles possess potential applications in supramolecular chemistry and biosystems. Thus development of new kinds of macrocycles is of significance. Herein, novel macrocycles containing Se-Se/Se-S bonds were synthesized via transformation between selenium related dynamic covalent bonds. A monomer containing two ebselen moieties was synthesized (M1). The Se-N bonds in M1 were reduced by dithiothreitol, forming Se-S linked dimer (D1). To realize the transformation from Se-S bonds to Se-Se bonds, guest molecules were added as template, triggering the formation of Se-Se linked dimer (D2). The formation of these two new kinds of macrocycles was determined by H-1 NMR and Se-77 NMR, and the necessity of guest molecules was also confirmed. The introduction of ebselen moieties and Se-S bonds or Se-Se bonds into macrocycles may endow it with new responsiveness and bioactivities, as well as new types of host-guest chemistry.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20334010,20474035,20473045,20574040 and 20573042)the Flemish government,the University of Leuyen and the F.W.0.Vlaanderen(Grant No.BIL 02/03).
文摘We have described the synthesis of a series of poly(aryl ether) dendrimers with telluride in the core and oligo(ethylene oxide) chains at the pe- riphery which act as glutathione peroxidase (GPx) mimics. These series of compounds were well characterized by H-NMR, 1 13C-NMR and ESI-MS. Using different ROOH (H2O2, cumene hydroperoxide) for testing the antioxidizing properties of these com- pounds, we have found that from generation 0 to 2, the activity of the dendritic GPx mimics first de- creased and then increased. This can be explained on the basis of a greater steric hindrance, going from generation 0 to 1, and stronger binding interactions going from generation 1 to 2. In other words, there exists a balance between binding interactions and steric hindrance that may optimize the GPx activity.
