A Laser Flash Photolysis Study of Curcumin in Dioxane–Water Mixtures¶
A Laser Flash Photolysis Study of Curcumin in Dioxane–Water Mixtures¶
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二恶烷-水混合物中姜黄素的激光闪光光解研究¶
DOI：
10.1562/0031-8655(2001)074
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
M. Rodgers
中科院分区：
文献类型：
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作者：
F. Ortica;M. Rodgers
摘要采用紫外-可见吸收光谱法和纳秒激光光解法研究了姜黄素[双（4-羟基-3-甲氧基苯基）-1,6-庚二烯-3,5-二酮]在1,4-二恶烷-水混合物中以不同体积比的二恶烷-水为原料的合成。发现瞬态特性与水量有关。在纯二氧六环中检测到烯醇型分子的三重态（λmax = 720 nm, τ = 3.2 μs），而在加水时，由于分子内氢键结构的扰动，分子以二酮型为主。这导致姜黄素三重态从二氧六环中提取氢，并形成相应的酮基自由基（λmax = 490 nm, τ ~ 10 μs）。在不同极性和溶剂（苯、环己烷和各种醇）中进行的激光闪光光解测量，可以确认瞬态分配，支持我们的解释。
Abstract Curcumin [bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] was studied by means of UV–VIS absorption spectroscopy and nanosecond laser flash photolysis in 1,4-dioxane–water mixtures in a series of dioxane–water volume ratios. The transient characteristics were found to be dependent on the amount of water. In pure dioxane the triplet state of the molecule in its enolic form was detected (λmax = 720 nm, τ = 3.2 μs), whereas upon water addition, the diketo form was found to prevail, because of the perturbation of intramolecular H-bonded structure. This led to hydrogen abstraction from dioxane by curcumin triplet state and the formation of the corresponding ketyl radical (λmax = 490 nm, τ ∼ 10 μs). Laser flash photolysis measurements, carried out in solvents of different polarity and proticity (benzene, cyclohexane and various alcohols), allowed the transient assignments to be confirmed, supporting our interpretation.