在过去的几十年中,超分子化学已成为化学和生物科学的中心主题。超分子结构越来越多地用于生物医学应用,特别是在需要特定刺激响应的设备中。富勒烯及其超分子组装体在生物医学科学和工程中获得了很高的知名度。需要敏感和选择性的方法来研究它们在各种应用领域中的配合物。考虑到这一点,我们设计了两种新的荧光双杯[4] 芳烃-咔唑偶联物(4和5)。在此,它们的合成和作为富勒烯 C 60和 C 70 的特定主体的能力被描述。新型化合物及其与 C 60和 C 70的配合物的光学性质通过紫外-可见光、稳态和时间分辨荧光光谱进行了深入研究。C 60和C 70由4和5络合的结合常数( K a )通过荧光技术确定。发现 C 70 @ 4超分子具有更高的稳定性(K a = 5.6 × 10 4 M -1 ; Δ G= -6.48 kcal/mol)。主体4和C 60 /C 70之间形成真正的包合物的证据是从低温下进行的核磁共振光谱获得的。在主客体组件(C
Calix[4]arene–carbazole-containing polymers: Synthesis and properties
摘要:
New highly fluorescent calix[4]arene-containing phenylene-alt-ethynylene-3,6- and 2,7-carbazolylene polymers (CALIX-PPE-CBZs) have been synthesized for the first time and their photophysical properties evaluated. Both polymers were obtained in good isolated yields (70-84%), having M-w ranging from 7660-26,700 g mol(-1). It was found that the diethynyl substitution (3,6- or 2,7-) pattern on the carbazole monomers markedly influences the degree of polymerization. The amorphous yellow polymers are freely soluble in several nonprotic organic solvents and have excellent film forming abilities. TG/DSC analysis evidences similar thermal behaviors for both polymers despite their quite different molecular weight distributions and main-chain connectivities (T-g, in the range 83-95 degrees C and decomposition onsets around 270 degrees C).The different conjugation lengths attained by the two polymers dictates much of their photophysical properties. Thus, whereas the fully conjugated CAUX-PPE-2,7-CBZ has its emission maximum at 430 nm (E-g = 2.84 eV; Phi(F) = 0.62, CHCl3), the 3,6-linked counterpart (CALIX-PPE-3,6-CBZ) fluoresces at 403 nm with a significant lower quantum yield (E-g = 3.06 eV; Phi(F) = 0.31, CHCl3). The optical properties of both polymers are predominantly governed by the intrachain electronic properties of the conjugated backbones owing to the presence of calix[4]arenes along the polymer chain which disfavor significant interchain interactions, either in fluid- or solid-state. (C) 2012 Elsevier Ltd. All rights reserved.