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大四写论文金虫 (正式写手)
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The most commonly used precatalysts for the Sonogashira reaction include [PdCl2ACHTUNGTRENUNG(PPh3)2],PdCl2/PPh3, and [PdACHTUNGTRENUNG(PPh3)4] with CuI as cocatalyst, which are effective for very reactive organic halides (e.g., vinyl and aryl iodides). We first utilized the [PdACHTUNGTRENUNG(PPh3)4]/CuI catalyst to synthesize PSNs, and obtained PSN-1 to PSN-3 from the crosscoupling of BrPh-D4R with 1–3, respectively. Progress of the reaction was evaluated by means of the residual amount of bromine. Energy-dispersive X-ray fluorescence spectroscopic data revealed that the Br/Si molar ratio of the obtained PSNs (after 48 h of the reaction; see details in the Experimental Section) was about 0.55, which corresponds to 45% conversion of phenyl bromides. As aryl bromides are less reactive electrophiles in Sonogashira coupling, a more active catalyst is needed. Palladium catalysts incorporating sterically demanding,electron-rich phosphines can furnish unusually high reactivity in a wide spectrum of coupling reactions. In particular, PtBu3 and bis(1-adamantyl)benzylphosphine ((1-Ad)2PBn) have proved to be exceptionally effective ligands for the Sonogashira reaction. Therefore,we tested Na2PdCl4/ACHTUNGTRENUNG[tBu3PH]BF4/CuI as precatalyst for our system.The phosphonium salt was used as a ligand precursor because it is insensitive toward oxidation and hence easily handled.[26e] The Br/Si molar ratios of PSN-1 to PSN-3 obtained with the Na2PdCl4/ACHTUNGTRENUNG[tBu3PH]BF4/CuI precatalyst were 0.13, 0.09, and 0.08, respectively, which suggests that less than one phenyl bromide moiety per D4R cage was left in the polymer networks. Thus, the present catalytic system was effective enough for constructing the PSNs.To investigate the effects of the length and connection points of the ethynyl compounds on physicochemical properties of the resulting PSNs, all reactions were carried out under the same conditions (concentration of the D4R compound, catalyst loading, reaction temperature and time, and molar ratio of ethynyl to aryl bromide groups). |
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武汉一心一译 
捐助贵宾 (著名写手)
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- 专业: 高分子合成化学
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大四写论文: 金币+50, ★★★很有帮助 2015-03-20 13:15:22
大四写论文: 金币+50, ★★★很有帮助 2015-03-20 13:15:22
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The most commonly used precatalysts for the Sonogashira reaction include [PdCl2ACHTUNGTRENUNG(PPh3)2],PdCl2/PPh3, and [PdACHTUNGTRENUNG(PPh3)4] with CuI as cocatalyst, which are effective for very reactive organic halides (e.g., vinyl and aryl iodides). 对于薗头偶合反应，最常见的预催化剂包括[PdCl2ACHTUNGTRENUNG(PPh3)2]，PdCl2/PPh3以及[PdACHTUNGTRENUNG(PPh3)4]和CuI(助催化剂)混合物, 它们对催化高活性有机卤化物（例如乙烯基、芳基碘化物），也是有效的。 We first utilized the [PdACHTUNGTRENUNG(PPh3)4]/CuI catalyst to synthesize PSNs, and obtained PSN-1 to PSN-3 from the crosscoupling of BrPh-D4R with 1–3, respectively. 首先我们利用[PdACHTUNGTRENUNG(PPh3)4]/CuI催化剂来合成PSNs，同时对BrPh-D4R与BrPh-D4R 1–3分别进行交叉耦合，从而得到PSN-1 PSN-2 PSN-3. Progress of the reaction was evaluated by means of the residual amount of bromine. Energy-dispersive X-ray fluorescence spectroscopic data revealed that the Br/Si molar ratio of the obtained PSNs (after 48 h of the reaction; see details in the Experimental Section) was about 0.55, which corresponds to 45% conversion of phenyl bromides. 运用残余的溴，对反应过程进行评价。能量色散x射线荧光光谱数据显示，所获得的PSNs的Br / Si摩尔比率（反应48小时后，参见具体的实验部分）约为0.55，相当于45%的溴苯转换。 As aryl bromides are less reactive electrophiles in Sonogashira coupling, a more active catalyst is needed. Palladium catalysts incorporating sterically demanding,electron-rich phosphines can furnish unusually high reactivity in a wide spectrum of coupling reactions. 由于芳基溴代物，在薗头偶合反应中，是低活性亲电体，所以需要一种活性更高的催化剂。一种结合钯催化剂，有空间需求的，富电子的膦类化合物，能在耦合反应的宽频谱中，提供非比寻常的高活性。 In particular, PtBu3 and bis(1-adamantyl)benzylphosphine ((1-Ad)2PBn) have proved to be exceptionally effective ligands for the Sonogashira reaction. Therefore,we tested Na2PdCl4/ACHTUNGTRENUNG[tBu3PH]BF4/CuI as precatalyst for our system. 值得一提的是，PtBu3 和 二度（1-金刚烷基）苄基磷化氢 ((1-Ad)2PBn)，被证明是薗头偶合反应，格外有效的配体。因此我们测试了预催化剂Na2PdCl4/ACHTUNGTRENUNG[tBu3PH]BF4/CuI，已确定其是否符合我们的系统。 The phosphonium salt was used as a ligand precursor because it is insensitive toward oxidation and hence easily handled.[26e] The Br/Si molar ratios of PSN-1 to PSN-3 obtained with the Na2PdCl4/ACHTUNGTRENUNG[tBu3PH]BF4/CuI precatalyst were 0.13, 0.09, and 0.08, respectively, which suggests that less than one phenyl bromide moiety per D4R cage was left in the polymer networks. 鏻盐被当作一种配位前体，因为它对氧化不敏感，而易于处理。[26e] Na2PdCl4/ACHTUNGTRENUNG[tBu3PH]BF4/CuI作为预催化剂，得到的PSN-1 PSN-2 PSN-3的Br/Si摩尔比，分别是0.13, 0.09, 和 0.08，这表明，每D4R笼 有低于一个溴苯部分的含量，被留在了聚合物网络中。 Thus, the present catalytic system was effective enough for constructing the PSNs.To investigate the effects of the length and connection points of the ethynyl compounds on physicochemical properties of the resulting PSNs, all reactions were carried out under the same conditions (concentration of the D4R compound, catalyst loading, reaction temperature and time, and molar ratio of ethynyl to aryl bromide groups). 因此，目前的催化体系有足够的活性，催化PSNs的生成。为了调查，乙炔基化合物的接点和长度，对生成物PSNs的物化性能的影响，所有的反应都在相同的条件下进行，形同的条件有D4R化合物的浓度，催化剂量，反应温度和反应时间，以及 乙炔基与芳基溴铵组的摩尔比。 |
2楼2015-03-20 12:26:00