Photodimerization of cinnamic acids controlled by molecular assemblies of surfactant amine N-oxides
Photodimerization of cinnamic acids controlled by molecular assemblies of surfactant amine N-oxides
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表面活性剂胺 N-氧化物分子组装控制肉桂酸的光二聚
DOI：
10.1039/a702413d
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Y. Sawaki
中科院分区：
文献类型：
--
作者：
Tomotaka Nakamura;K. Takagi;M. Itoh;K. Fujita;Hiroyuki Katsu;T. Imae;Y. Sawaki
肉桂酸1的UV照射涉及与表面活性剂胺N-氧化物（CnDAO，n = 12、14和16）的复合物作为水中的囊泡，导致形成环二聚体（即β-、δ-truxinic和/或α-truxillic酸†）。降低1与CnDAO的摩尔比导致囊泡转变为棒状胶束，并且环二聚体的产率降低。加入HCl或NaOH的水溶液中的1和CnDAO带来了急剧的变化，在自组装结构从囊泡到微乳液或棒状胶束，伴随着在光解的复合物1的产物分布的变化。在向1和C16 DAO系统中加入光惰性羧酸、苯丙酸和棕榈酸后，棒状胶束通过与C16 DAO形成复合物而变成囊泡，导致在加入苯丙酸后观察到光二聚化中的稀释效应。然而，未观察到棕榈酸的稀释效应。这被认为是由于1与囊泡中的酸的混合程度的差异。这些结果表明，1的光二聚纳入CnDAO是由各种分子组装，即棒状胶束和均匀或异质囊泡控制。
UV irradiation of cinnamic acids 1 involving a complex with surfactant amine N-oxides (CnDAO, n = 12, 14 and 16) as vesicles in water leads to the formation of cyclodimers (i.e. β-, δ-truxinic and/or α-truxillic acids†). Decreasing the molar ratios of 1 to CnDAO causes the vesicles to transform into rod-like micelles and the yield of the cyclodimers decreases. The addition of HCl or NaOH to aqueous solutions of 1 and CnDAO brings about sharp changes in the self-assembly structures from vesicles to micro emulsions or rod-like micelles, accompanied by a change in product distribution in the photolysis of the complex 1. Upon addition of photoinactive carboxylic acids, phenylpropionic and palmitic acids to the 1 and C16DAO system, the rod-like micelles change into vesicles by formation of a complex with C16DAO leading to the observation of a dilution effect in the photodimerization upon addition of phenylpropionic acid. However, no dilution effect is observed for the palmitic acid. This is found to be attributable to the difference in degrees of mixing of 1 with the acids in the vesicles. These results show that photodimerization of 1 incorporated in CnDAO is controlled by a variety of molecular assemblies, i.e. rod-like micelles and homogeneous or heterogeneous vesicles.