Synthesis of Optically Active Poly(m-phenyleneethynylene鈥揳ryleneethynylene)s Bearing Hydroxy Groups and Examination of the Higher Order Structures

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• 作者：Hiromitsu Sogawa ; Masashi Shiotsuki ; Takehiro Hirao ; Takeharu Haino ; Fumio Sanda
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：October 22, 2013
• 年：2013
• 卷：46
• 期：20
• 页码：8161-8170
• 全文大小：514K
• 年卷期：v.46,no.20(October 22, 2013)
• ISSN：1520-5835

文摘

Novel optically active poly(m-phenyleneethynylene鈥揳ryleneethynylene)s bearing hydroxy groups with various arylene units {poly[(S)-/(R)-1鈥?b>3a]鈥損oly[(R)-1鈥?b>3e] and poly[(S)-2鈥?b>3a]} were synthesized by the Sonogashira鈥揌agihara coupling polymerization of 3,5-diiodo-4-hydroxy-C₆H₄CONHCH(CH₃)COXC₁₂H₂₅ [(S)-/(R)-1 (X = O), (S)-2 (X = NH)] with HC鈮鈥揂r鈥揅鈮H [3a (Ar = 1,4-C₆H₄), 3b (Ar = 1,4-C₆H₄-1,4-C₆H₄鈭?, 3c (Ar = 1,4-C₆H₄-1,4-C₆H₄-1,4-C₆H₄鈭?, 3d (Ar = 2,5-dihexyl-1,4-C₆H₂), 3e (Ar = 2,5-didodecyl-1,4-C₆H₂)]. The yields and number-average molecular weights of the polymers were in the ranges 60鈥?4% and 7,000鈥?9,500 with no correlation between the yield and the M_n. Circular dichroism (CD), UV鈥搗is, and fluorescence spectroscopic analyses indicated that poly[(S)-1鈥?b>3a]鈥損oly[(S)-1鈥?b>3c] and poly[(S)-2鈥?b>3a] formed predominantly one-handed helical structures in THF, while poly[(S)-1鈥?b>3d] and poly[(S)-1鈥?b>3e] showed no evidence for forming chirally ordered structures. All polymers emitted blue fluorescence. The solution state IR measurement revealed the presence of intramolecular hydrogen bonding between the amide groups at the side chains of poly[(S)-1鈥?b>2a]. The helical structures and helix-forming abilities of the polymers were analyzed by the molecular mechanics (MM), semiempirical molecular orbital (MO) and density functional theory (DFT) methods. Tube-like structures, presumably formed by perpendicular aggregation of the helical polymers, were observed by atomic force microscopy (AFM).