Novel 1,2,3-triazolium-functionalized starch derivatives: Synthesis, characterization, and evaluation of antifungal property

Synthesis, characterization, and antifungal evaluation of novel 1,2,3-triazolium-functionalized starch derivative

“…Besides, the appearance of the additional signals of alkyl protons linked to 1,2,3-triaole at 4.69 and 2.46 ppm further proves the successful CuAAC reaction [21]. Moreover, the 1 H NMR spectrum of starch derivative (D) corroborates the quaternization through the disappearance of the peak corresponding to the proton of the 1,2,3-triazole group at 7.62 ppm and the appearance of new signal for the proton of the 1,2,3-triazolium at 8.40 ppm [19,32].…”

“…The starch derivative bearing 1,2,3-triazole, obtained by cuprous-catalyzed azide-alkyne cycloaddition of 6-azido-6-deoxy starch and 3-butyn-1-ol, may be also straightforwardly detected by the new peaks of the 1,2,3-triazole linker at 144.58 and 123.99 ppm [22]. Meanwhile, the alkyl carbons linked to both the 1,2,3-triazole and hydroxyl resonate at 29.21 and 60.74 ppm, respectively [21]. Finally, the quantitative formation of 1,2,3-triazolium unit is also confirmed in the starch derivative bearing 1,2,3-triazolium by 13 [38].…”

“…Subsequently, the azide peak at 2105 cm -1 disappears completely when the C6-N3 is transformed to 1,2,3-triazole and a new absorption band at about 1554 cm -1 appears [22]. After the quaternization, the new characteristic band at 1577 cm -1 is assigned to 1,2,3-triazolium groups [21]. Besides, two bands at 1496 and 728 cm -1 corresponding to the C=C stretching vibration and the =C-H deformation vibration mode of the phenyl group are newly appeared [28,29].…”

“…The analyses of elemental carbon, hydrogen, and nitrogen in starch derivatives were performed on a Vario EL III (Elementar, Germany). The degrees of substitution (DS) of starch derivatives were calculated on the basis of the percentages of carbon and nitrogen according to the following equations [21]:…”

“…There are no absorption peaks appeared ranging from 200 to 400 nm because of absence of chromophore in starch. The UV-vis spectrum of starch derivative bearing 1,2,3-triazole (C) exhibits one peak centered at 220 nm corresponding to the 1,2,3-triazole ring [21]. The absorption peak of 1,2,3-triazolium is red-shifted from 220 to 225 nm because of the change in electron configuration of 1,2,3-triazole after the quaternization with benzyl bromide.…”