Synthesis and Chiroptical Properties of L‐Serine‐Based Poly(phenylacetylenes)
Synthesis and Chiroptical Properties of L‐Serine‐Based Poly(phenylacetylenes)
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DOI：
10.1080/10601320601188091
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发表时间：
2007-03
期刊：
影响因子：
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通讯作者：
Haichao Zhao;F. Sanda;T. Masuda
中科院分区：
文献类型：
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作者：
Haichao Zhao;F. Sanda;T. Masuda
L-丝氨酸基含羟基苯乙炔，N-(α-叔丁氧羰基)-L-丝氨酸4-乙炔基苯酰胺(1)，以及羟基保护的对应物，N-(α-叔丁氧羰基)-O-三甲基甲硅烷基-L-丝氨酸 以(nbd)Rh+[η6-C6H5B−(C6H5)3]为催化剂，将4-乙炔基苯酰胺(2)聚合，以良好的收率获得相应的中等分子量的聚合物[poly(1)和poly(2)]。旋光和CD光谱数据表明，poly(1)在DMF、MeOH和THF中以螺旋构象存在；除这些溶剂外，聚（2）在 CHCl3 和甲苯中也呈现单手螺旋结构。聚(2) 的螺旋紧密度取决于溶剂的极性。加热后，聚(1)和聚(2)在DMF、MeOH和THF中略微降低CD强度，而聚(2)在甲苯中增加CD强度。通过将环己烷添加到THF中，聚(1)和聚(2)的螺旋构象是稳定的。
L‐Serine‐based hydroxy group‐containing phenylacetylene, N‐(α‐tert‐butoxycarbonyl)‐L‐serine 4‐ethynylphenylamide (1), and the hydroxy group‐protected counterpart, N‐(α‐tert‐butoxycarbonyl)‐O‐trimethylsilyl‐L‐serine 4‐ethynylphenylamide (2) were polymerized with (nbd)Rh+[η6‐C6H5B−(C6H5)3] as a catalyst to obtain the corresponding polymers [poly(1) and poly(2)] with moderate molecular weights in good yields. The polarimetric and CD spectroscopic data indicated that poly(1) existed in a helical conformation in DMF, MeOH, and THF; and that poly(2) also took a one‐handed helical structure in CHCl3 and toluene in addition to these solvents. The helical tightness of poly(2) depended on the polarity of the solvents. Upon heating, poly(1) and poly(2) slightly decreased the CD intensity in DMF, MeOH and THF, while poly(2) increased it in toluene. The helical conformation of poly(1) and poly(2) was stable by adding cyclohexane to THF.