Templating Photodimerization of Coumarins within a Water-Soluble Nano Reaction Vessel
作者:S. Karthikeyan、V. Ramamurthy
DOI:10.1021/jo0606498
日期:2006.8.1
An octahedral Pd nanocage serves as a reaction vessel to control photodimerization of coumarins in water. The coumarin derivatives explored in this study react within the Pd nanocage to selectively yield a syn head−head dimer, whereas in water, they yield either a mixture of dimers or a different isomer. The selective dimerization is interpreted to mean that the monomers are preorganized by the cage
八面体钯纳米笼用作控制容器中香豆素光二聚化的反应容器。在这项研究中探索的香豆素衍生物在Pd纳米笼中发生反应,选择性地产生了一个syn head - head二聚体,而在水中,它们要么生成二聚体的混合物,要么生成不同的异构体。选择性二聚化被解释为意味着单体通过弱的分子间作用力被笼子预组织。与先前用于控制光二聚化反应的几何结构的其他宿主相比,在纳米笼中获得的选择性更为通用和可预测。
Manipulating Photochemical Reactivity of Coumarins within Cucurbituril Nanocavities
作者:Nilotpal Barooah、Barry C. Pemberton、J. Sivaguru
DOI:10.1021/ol801256r
日期:2008.8.7
Coumarin derivatives that are either cationic (7-ammonium) or neutral (7-hydroxy, 7-methoxy, 6-methyl) form a 1:2 host-guest complex with cucurbit[8]uril (CB[8]). Direct irradiation of these coumarin@CB[8] complexes in water gives head-to-tail (HT) adduct as the major product. The nature of the functional group (polar or nonpolar) at the 6 or 7 position on the coumarin dictates the type of HT adduct
Applications of a Bis-Urea Phenylethynylene Self-Assembled Nanoreactor for [2 + 2] Photodimerizations
作者:Sandipan Dawn、Sahan R. Salpage、Brent A. Koscher、Andreas Bick、Arief C. Wibowo、Perry J. Pellechia、Linda S. Shimizu
DOI:10.1021/jp505304n
日期:2014.11.13
potentially photoreactive guests to interrogate the utility of the one-dimensional nanochannels of a porous host to absorb and facilitate the reaction of encapsulated guests. The host is a columnar self-assembled phenylethynylene bis-urea macrocycle, which absorbs guests, including coumarin, 6-methyl coumarin, 7-methyl coumarin, 7-methoxy coumarin, acenaphthylene, cis-stilbene, trans-stilbene, and trans-β-methylstyrene
密闭环境可用于通过影响反应物的组织,改变被捕获分子的迁移率,促进一个反应途径或选择性稳定产物来改变反应的选择性。该手稿利用了一系列潜在的光反应性客体来询问多孔主体的一维纳米通道的效用,以吸收并促进被包封的客体的反应。宿主是柱状自组装的苯基乙炔基双脲大环化合物,可吸收来宾,包括香豆素,6-甲基香豆素,7-甲基香豆素,7-甲氧基香豆素,,顺式-sti,反式-二苯乙烯和反式的-β-甲基苯乙烯,得到结晶包合物。我们使用粉末X射线衍射检查了主体:客体复合物的结构,这表明它们是有序的高度结晶的材料。使用固态交叉极化幻角旋转13 C 1的研究1 H-CP-MAS NMR光谱表明,客人相对于宿主是可移动的。在紫外线照射下,我们观察到香豆素,6-甲基香豆素,7-甲基香豆素和ena的选择性光二聚反应,而其他底物即使在长时间紫外线照射下也没有反应。蒙特卡洛大法则的模拟结果表明,反应性宾客是紧密配对的,并以有
Photodimerization of coumarin revisited: Effects of solvent polarity on the triplet reactivity and product pattern
作者:Thomas Wolff、Helmut Görner
DOI:10.1039/b312335a
日期:——
results for the derivatives are very similar and the main difference is a lower Φisc for 1 in aqueous solution. The published product yields and patterns from preparative irradiations as a function of solvent polarity are discussed in view of the triplet properties.
Evaluating photodimerization of 6-methylcoumarin mediated by cucurbit[8]uril through mechanical grinding – Supramolecular effects of additives
作者:Barry C. Pemberton、Angel Ugrinov、J. Sivaguru
DOI:10.1016/j.jphotochem.2013.01.005
日期:2013.3
crystal X-ray determination of 1 from water reveals that the coumarins are oriented in a head-to-head fashion with the distance between the double bonds being 4.695 Å, a distance that is greater than the required Schmidt distance of 4.2 Å for efficient photodimerization in the crystalline state. Enhancement of photoreactivity of 1 upon mechanical grinding with additives appears to be the result of a combination