"2,6-聚胺薁"

Abstract

本篇論文主要探討比較 2-胺基衍生物的單體、二聚體及聚合物的合成與性質。合成方面，我們使用多樣的鈀催化胺化、醯胺化或胺基甲酸叔丁酯化偶聯反應，得到多種不同的胺基薁衍生物。其中首次將 Buchwald 二級醯胺化偶聯反應應用於聚合物的合成得到叔丁氧羰基保護的聚胺薁 48，其在酸性條件中去保護可得 2,6-方向連接頭尾相連的聚胺薁 51。 於所得到的胺基薁衍生物的單體、二聚體及聚合物的光物理性質比較可以發現，叔丁氧羰基保護的胺基薁共軛性較差，於吸收光譜中長波吸收僅略微紅移；然而未保護的胺基薁其共軛性良好，吸收光譜中長波吸收自單體到聚合物紅移了近 200 nm，且能隙也縮小了近 1.4 eV，於電化學性質分析也可發現自單體到聚合物 HOMO 上升，而 LUMO 下降。 另一方面，我們發現胺基薁衍生物的單體、二聚體及聚合物在酸性條件中可質子化。然而其質子化並未發生在胺基，而是在薁的 C1 或 C3 位置。質子化後叔丁氧羰基保護的胺基薁共軛提升，於吸收光譜中可看到長波吸收峰最大值隨聚合度增加明顯紅移；而對於未保護的胺基薁，質子化也不會影響其共軛性，長波吸收峰最大值於質子化後略微紅移而 HOMO 則顯著降低。 2,6-聚胺薁 51 於 591 nm 有很強的吸收，而於質子化後更紅移到 670 nm。其能帶隙於質子化前後皆在 1.65 eV 左右。聚胺薁 51 雖為一種胺基芳香性聚合物，然而其特殊性質說明其獨立於一般胺基芳香性聚合物。其與聚苯胺完全不同的特性使其而成為一種全新的共軛低能帶隙有機聚合物。

This thesis describe the syntheses and properties of a new series of conjugated polymers: 2,6-linked polyaminoazulene, and its related compounds. Different kinds of monomeric, dimeric and polymeric aminoazulene derivatives have been synthesized via various types of Pd-catalyzed amination, primary and secondary amidation and carbamation. Among these, Buchwald secondary carbamation has been firstly applied to polymer synthesis to afford the BOC-protected polyaminoazulene 48, which could undergo deprotection under acidic conditions to yield the corresponding polyaminoazulene 51. The photophysical properties of these aminoazulene derivatives suggest that the BOC-protected aminoazulenes show poor conjugation. Little bathochromic shifts of longer wavelength absorption maximum were observed when the degree of polymerization became larger. However, excellent conjugation was observed in the case of unprotected polyaminoazulenes. The longer wavelength absorption maximum of the polymer showed about 200 nm bathochromic shift in comparison with the corresponding monomer, and the energy gap for the polymer was 1.66 eV. The electrochemical behavior of unprotected aminoazulenes have been studied, the HOMO energy increased with the degree of polymerization while the LUMO energy decreased. Protonation at the C1 or C3 position of aminoazulene derivatives occured under acidic conditions. These processes resulted in enhancement of conjugation of BOC-protected aminoazulenes. In UV-Vis absorption spectra an obvious bathochromic shift of longer wavelength absorption were observed when the degree of polymerization became larger. Furthermore, in the case of unprotected aminoazulenes, the conjugation was not interrupted when protonated, and the HOMO energy are strongly reduced. The longer wavelength absorption maximum of polyaminoazulene 51 was at 591 nm and became 670 nm after protonation, and the band gap were around 1.65 eV both in neutral and acidic conditions. This study suggests that 2,6-linked polyaminoazulene is quite unique in comparison with other kinds of polyaminoarenes. They are not polyaniline.