In order to evaluate the role of a substituent in sensitivity enhancement of meso-substituted trimethine cyanine dyes as sensitizers for photo-polymerization, we prepared a series of cyanine dyes, 3-ethyl-2-3-(3-ethyl-3H-2-benzothiazolylidene)-2-[2-(4 or 3-X-phenyl)ethenyl]-1-propenyl} benzothiazolium iodide, 1a–k (a: X = p-NMe2, b: X = p-OMe, c: X = p-CH3, d: X = H, e: X = p-Cl, f: X = p-CF3, g: X = p-CN, h: X = p-NO2, i: X = m-OMe, j: X = m-CH3, k: X = m-Cl). The sensitivity for the photo-polymerization tends to be greater for substituents with greater electron-donating ability. In the series, the sensitivity of dye 1a was 2.1 mJ/cm2 higher than the other sensitivities. The sensitivities of dye 2 having a 2-(9-julolidinyl)ethenyl group was high: 1.5 mJ/cm2 and that of dye 3 having a 2-(9-julolidinyl)-1-methylethenyl group was the highest: 0.7 mJ/cm2, among all dyes tested here.
为了评估取代基在提高间位取代的三美汀
氰染料作为光聚合敏化剂中的作用,我们制备了一系列
氰染料,3-乙基-2-3-(3-乙基-3H-2-
苯并噻唑亚基)-2-[2-(4或3-X-苯)
乙烯]-
1-丙烯基}
苯并噻唑铵碘化物,1a–k(a: X = p-NMe2, b: X = p-OMe, c: X = p-
CH3, d: X = H, e: X = p-Cl, f: X = p-
CF3, g: X = p-CN, h: X = p-
NO2, i: X = m-OMe, j: X = m- , k: X = m-Cl)。光聚合的敏感性对于电子供体能力更强的取代基往往更高。在这一系列中,
染料1a的敏感性比其他
染料高出2.1 mJ/cm²。
染料2含有2-(9-茴香啶基)
乙烯基,其敏感性较高:1.5 mJ/cm²,而
染料3含有2-(9-茴香啶基)-1-甲基
乙烯基,其敏感性在所有测试的
染料中最高:0.7 mJ/cm²。