Simultaneous control of the stereospecificity and molecular weight in the ruthenium‐catalyzed living radical polymerization of methyl and 2‐hydroxyethyl methacrylates and sequential synthesis of stereoblock polymers
Simultaneous control of the stereospecificity and molecular weight in the ruthenium‐catalyzed living radical polymerization of methyl and 2‐hydroxyethyl methacrylates and sequential synthesis of stereoblock polymers
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DOI：
10.1002/pola.21469
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发表时间：
2006-06
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影响因子：
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通讯作者：
T. Shibata;K. Satoh;M. Kamigaito;Y. Okamoto
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文献类型：
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作者：
T. Shibata;K. Satoh;M. Kamigaito;Y. Okamoto
将甲基丙烯酸甲酯（MMA）和甲基丙烯酸羟乙酯（HEMA）的活性自由基聚合与溶剂介导的立体定向自由基聚合相结合，实现了MMA和HEMA的立体定向活性自由基聚合。在一系列钌配合物[RuCl 2（PPh 3）3、Ru（Ind）Cl（PPh 3）2和RuCp*Cl（PPh 3）2]中，Cp*-钌在氟醇如（CF 3）2C（Ph）OH中在0 °C下提供具有高度受控的分子量[重均分子量/数均分子量（Mw/Mn）= 1.08]和高间同立构规整度（r = 88%）的聚（甲基丙烯酸甲酯）。另一方面，羟基官能化单体HEMA与RuCp*Cl（PPh 3）2在N，N-二甲基甲酰胺和N，N-二甲基乙酰胺（DMA）中聚合，得到具有受控分子量（Mw/Mn = 1.12-1.16）的间同立构聚合物（r = 87-88%）。这是HEMA间规活性自由基聚合的第一个例子。在RuCp*Cl（PPh 3）2存在下，在80 °C下，诱导MMA的间规自由基聚合的氟醇[（CF 3）2C（Ph）OH]降低了HEMA聚合中的间规性，从而产生或多或少的具有受控分子量的无规聚合物（mm/mr/rr = 7.2/40.9/51.9%）。HEMA在两种溶剂中进行连续的活性自由基聚合，首先是DMA，然后是（CF 3）2C（Ph）OH，得到具有间同立构-无规立构链段的立构嵌段聚（甲基丙烯酸2-羟乙酯）。© 2006 Wiley Periodicals，Inc.聚合物科学杂志A部分：聚合物化学44：3609-3615，2006年
The stereospecific living radical polymerizations of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) were achieved with a combination of ruthenium-catalyzed living radical and solvent-mediated stereospecific radical polymerizations. Among a series of ruthenium complexes [RuCl2(PPh3)3, Ru(Ind)Cl(PPh3)2, and RuCp*Cl(PPh3)2], Cp*–ruthenium afforded poly(methyl methacrylate) with highly controlled molecular weights [weight-average molecular weight/number-average molecular weight (Mw/Mn) = 1.08] and high syndiotacticity (r = 88%) in a fluoroalcohol such as (CF3)2C(Ph)OH at 0 °C. On the other hand, a hydroxy-functionalized monomer, HEMA, was polymerized with RuCp*Cl(PPh3)2 in N,N-dimethylformamide and N,N-dimethylacetamide (DMA) to give syndiotactic polymers (r = 87–88%) with controlled molecular weights (Mw/Mn = 1.12–1.16). This was the first example of the syndiospecific living radical polymerization of HEMA. A fluoroalcohol [(CF3)2C(Ph)OH], which induced the syndiospecific radical polymerization of MMA, reduced the syndiospecificity in the HEMA polymerization to result in more or less atactic polymers (mm/mr/rr = 7.2/40.9/51.9%) with controlled molecular weights in the presence of RuCp*Cl(PPh3)2 at 80 °C. A successive living radical polymerization of HEMA in two solvents, first DMA followed by (CF3)2C(Ph)OH, resulted in stereoblock poly(2-hydroxyethyl methacrylate) with syndiotactic–atactic segments. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3609–3615, 2006