Ladderlike Oligomers; Intramolecular Hydrogen Bonding, Push-Pull Character, and Electron Affinity
摘要:
Symmetrical 2,5-bis(2-aminophenyl)pyrazines have been synthesized by application of the Stille coupling strategy. These cotrimers feature three important properties, namely strong intramolecular hydrogen bonding, push-pull character, and high electron affinity. The presence of intramolecular hydrogen bonds has been confirmed by H-1 NMR, IR spectroscopy, and single crystal X-ray diffraction. The hydrogen bond strength can be increased by substituting the amino groups with stronger electron-withdrawing functionalities. Despite the anticipated enhanced pi -conjugation through planarization, a hypsochromic shift was observed in the UV/Vis spectra, explained by a decrease in push-pull character. The electron affinity of the cotrimers was deduced from the first reduction potentials measured by cyclic voltammetry and is related to the electron-withdrawing character of the amino substituents. The results obtained have been compared with those of the corresponding 4-aminophenyl analogues and show that intramolecular hydrogen bonds can be used to design polymers with enhanced re conjugation as well as a high electron affinity.
[EN] POLYIMIDE PRECURSOR RESIN, PREPARATION METHOD THEREFOR AND USE THEREOF<br/>[FR] RÉSINE PRÉCURSEUR DE POLYIMIDE, SON PROCÉDÉ DE PRÉPARATION ET SON UTILISATION<br/>[ZH] 一种聚酰亚胺前体树脂及其制备方法和应用
申请人:[en]SHENZHEN INSTITUTES OF ADVANCED TECHNOLOGY CHINESE ACADEMY OF SCIENCES;[zh]中国科学院深圳先进技术研究院