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联烯是一种带有累积双键的1,2-丙二烯类衍生物,由于其结构独特,其2个双键上的3个碳原子的电子云密度不同,因此具有多种反应活性与选择性。研究表明:在联烯侧基上引入不同功能基团,使其聚合后可获得一系列性能优异的功能聚合物。由于联烯双键加成反应的多功能性,联烯衍生物已被用作多种功能通用材料的合成前体[1]。
联烯聚合的方法主要有自由基聚合、阳离子聚合、配位聚合和两性离子聚合等。自由基聚合存在分子量分布宽、结构规整度差等不足之处,因此,如何实现联烯的活性可控聚合成为化学工作者研究的热点之一。配位聚合由于其反应条件温和、所得聚合物分子量分布较窄、可获得高规整度聚合物等而受到了广泛关注。就联烯配位聚合来说,目前应用最广泛的主要是由Endo等[2-4]开发的[(η3-allyl)NiOCOCF3] 2/PPh3 (allyl:烯丙基)催化体系。配位聚合能够实现联烯与丁二烯、异氰酸酯及3-己基噻吩等单体嵌段共聚,得到一系列新型嵌段共聚物[5-7]。由于(η3-allyl)NiOCOCF3比较稳定,可与多种官能团共存,因此可制备有不同取代基的结构规整聚联烯。聚联烯末端的引发基团活性种很稳定,可通过分批加入单体获得嵌段共聚物;且联烯单体具有累积双键,在适当的条件下可选择性地进行1,2-或2,3-位聚合[8, 9],从而为制备功能高分子材料提供广阔的空间。如果联烯末端连有不同取代基团,聚合后连于主链的双键可以进一步反应制得新的功能性材料[10]。
除Ni催化体系外,其他能够实现联烯单体配位聚合的催化体系也陆续被开发出来,1996年,Endo等[8]开发出了能够使联烯聚合的Pd催化体系;1968年,Ploeg等[9]开发的Rh催化体系也能用于联烯的聚合;Schors等[10]曾提出Al-i-Bu3-VOCl3催化体系用于联烯的聚合;2017年,Cui等[11]提出的含Y等稀土金属配合物催化体系用于芳基联烯的聚合,并得到高2,3-选择性聚合的聚联烯;1998年,Yamamoto等[12]使用铑催化剂RhH(PPh3)4引发芳基取代联烯的聚合。文献[8, 10, 11]开发的Pd、Rh稀土催化体系如图1所示。这些催化体系由于合成方法复杂、原料价格昂贵等原因,应用上存在着一定的局限性。
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用于联烯配位聚合的[(η3-allyl)NiX]2催化体系最早是由Imaizumi等提出,Imaizumi等[13,14]使用未取代的以及烷基取代的丙二烯,用Ni(0)催化剂以及[(η3-allyl)NiBr]2聚合得到无色高度结晶的聚联烯,其表征数据如表1所示。该聚联烯可溶于有机溶剂,为1,2-聚合产物,并呈现高度规整的构象。另外,Jacobs等[15] 报道了[(η3-allyl)NiX]2体系聚合烷氧基联烯的方法,得到结晶的不溶性聚合物(方案1)。
Expt. No.1) Catalyst cMonomer/(mol·L−1) Solvent2) T/ ℃ t/h Yield/% $ { { { {M_{\rm n}^{3 )} } } } }$ Complex c/(mmol·L−1) A-8 (π-C8H12)2Ni 2 2 Benzene 40 24 67.5 … A-30 (π-C8H12)2Ni 2 2 Benzene 7 48 18.0 … A-31 (π-C8H12)2Ni 2 2 Benzene 0 48 0 … A-111 (π-C3H5NiBr)2 2 1 Benzene 15 24 92.5 … A-98 (π-C3H5NiBr)2 8.4 2.7 Toluene 40 1 46.4 1.07×105 A-116 (π-C3H5NiBr)2 8.4 2.6 Toluene 0 20.5 85.0 1.38×106 A-15 Ni(acac)24)-AlEt3 25) 2 Benzene 40 24 16.26) … A-117 Ni(acac)2 2 2 Benzene 40 24 0 … A-118 (PPh3)2NiBr2 2 2 Benzene 40 24 0 … 1)Polymerization was carried out under purified nitrogen and the polymer was isolated as usual. As an antioxidant for the polymer 2, 2'-methylenebis(4-methyl-6-t-butylphenol) was used. 2)Solvents were deoxygenated and the water content was kept below 10 μg/mL. In toluene a comparable yield of the polymer having the same microstructure was obtained as in benzene, but the yield was lower in n-hexane and diethyl ether than in benzene. 3)The number average molecular weight was measured by a membrane osmometer (Mechrolab Inc., Model 502). 4)acac=acetylacetonate. 5)This is the concentration of Ni(acac)2 and the mole ratio of AlEt3/Ni(acac)2 is 2. 6)The polymer was insoluble in benzene. -
在π-烯丙基镍催化体系中,[(η3-allyl)NiOCOCF3]2是一种比较稳定的催化体系[15],曾被用于丁二烯[16]和异腈[17]的聚合。该催化体系用于联烯聚合时,若不添加任何配体,会生成不溶于有机溶剂的聚合物[15];若添加三苯基膦配体,则能得到可溶于有机溶剂的聚联烯。1994年,Endo等[2]首次将[(η3-allyl)NiOCOCF3]2用于联烯的活性聚合,将双-(1,5-环辛二烯)镍(Ni(COD)2)与三氟乙酸烯丙酯在甲苯中反应得到[(η3-allyl)NiOCOCF3]2,并与PPh3以1∶1的物质的量之比混合,0 ℃下聚合甲氧基联烯单体,得到分子量分布较窄(PDI为1.1左右)的聚联烯。使用1H-NMR定量检测聚合物中的双键含量,1,2-和2,3-聚合比例约为30∶70(如图2所示);通过动力学实验证明该聚合反应为活性聚合(如图3所示),这项工作为后人在联烯的嵌段共聚以及制备功能聚联烯等领域的研究奠定了基础。
1997年,Tomita等[3]使用烯丙基镍催化剂进行联烯的活性聚合实验(如方案2所示),并提出了[(η3-allyl)NiOCOCF3]2/PPh3催化联烯聚合的机理(如方案3(a)和3(b)所示)。作为第五配体,在镍催化剂上配位的烷氧基基团可以插入烯丙基镍催化剂以生成1-烷氧基烯丙基。将配位单体连续插入到增长的烷氧基烯烃中可生成相应的聚合物(方案3(a))。这是由于活性链末端具有2个可能的C―C键形成位置(α-烷氧基和γ-烷氧基),可分别将1,2-和2,3-聚合单元引入聚合物中(方案3(b)),而空间位阻较大的烷氧基取代基倾向于降低其在邻位形成C―C键的可能性,因此,2,3-聚合单元的含量略有增加。
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Tomita等[19]研究了不同溶剂对π-烯丙基镍催化体系聚合联烯的影响。Tomita等研究表明:烯丙基镍催化联烯衍生物聚合时,使用质子溶剂如EtOH,联烯衍生物可进行活性聚合,并得到高产率、窄分子量分布的聚联烯;而使用非质子溶剂如甲苯时,聚合速率比质子溶剂中的相应值更快,1,2-聚合的选择性也比使用质子溶剂中的选择性更高。Tomita等还证明1,2-和2,3-聚合之间的选择性可通过控制EtOH的浓度,增加混合溶剂中EtOH的含量,则所得聚合物中的1,2-聚合单元的含量从27%增加到63%,而分子量及其分布几乎恒定。Tomita等为了探究不同溶剂中联烯聚合的反应速率,使用[(η3-allyl)NiOCOCF3]2/PPh3催化具有相对较低聚合活性的烷基以及苯基联烯(如方案4所示),结果如表2所示:正戊基联烯在不同溶剂中聚合的动力学系数(kobs)为DMSO<EtOH<吡咯<吲哚;所得聚合物中1,2-聚合单元的含量也以相同的顺序增加。使用苯基联烯为单体时,聚合反应速率在质子溶剂(如吡咯)中加快,但是所得聚合物始终由特定的2,3-聚合单元组成,可能是由于烯烃单元与相邻芳族取代基的共轭使2,3-聚合产物具有较高的热力学稳定性。
Run Monomer Solvents kobs/(L·mol−1·h−1) Yield/% x∶y Mn Mw/Mn 1 20 Toluene 0 0 2 20 DMSO/toluene1) 2.6 49 27∶73 3.2×103 1.03 3 20 EtOH/toluene1) 16.4 99 28∶72 8.6×103 1.07 4 20 Pyrrole/toluene1) 62.2 99 31∶69 7.1×103 1.08 5 20 Indole/toluene1) 86.9 94 31∶69 7.6×103 1.08 6 20 Phenol/toluene1) 224.0 93 49∶51 7.6×103 1.08 7 21 Toluene 0 0 8 21 Pyrrole 6.2 98 0 5.6×103 1.05 1)Volume ratio is 1 -
1995年,Endo等[20]使用具有不同烷氧取代基的联烯单体,探讨单体上取代基对聚合反应的影响(如方案5所示)。研究表明,不同的烷氧基取代基对聚合产率影响不大,均能以高产率得到聚联烯(表3)。然而,1,2-和2,3-聚合的比例受到联烯单体上取代基的轻微影响。增大取代基的空间位阻,聚合物中2,3-聚合单元的含量增加,拥有较小位阻的甲氧基取代联烯主要得到1,2-聚合产物,而拥有较大位阻的苯氧基联烯聚合所得2,3-聚合产物的比例高达80%,且聚合物的活性端在惰性气氛下是稳定的,可以保持一周以上且活性端不会减少。
Run M cM/cI Yield/% x∶y Mn Mw/Mn 1 a 65 91 70∶30 8 290 1.06 2 b 50 93 70∶30 7 670 1.08 3 c 49 84 70∶30 5 870 1.11 4 d 52 92 80∶20 5 990 1.13 5 e 50 82 70∶30 6 050 1.11 6 f 51 88 80∶10 5 590 1.13 7 100 100 90∶10 9 880 1.08 2003年,Endo等[21]使用[(η3-allyl) NiOCOCF3]2/PPh3催化体系在二氯甲烷中聚合酯基取代的联烯,1H-NMR显示所得聚合物均为2,3-聚合产物,且为活性聚合。若联烯单体带有吸电子基团,倾向于形成2,3-聚合产物。
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Huang等[22]对π-烯丙基镍催化联烯活性聚合及聚联烯自组装性能进行了研究。他们设计合成了一种两亲性接枝共聚物聚(6-甲基-1,2-庚二烯-4-醇)-g-聚(甲基丙烯酸-2-(二甲基氨基)乙酯)(PMHDO-g-PDMAEMA),将π-烯丙基镍引发的联烯活性配位聚合与单电子转移-活性自由基聚合(SET-LRP)巧妙组合。首先通过[(η3-allyl)-NiOCOCF3] 2引发的6-甲基-1,2-庚二烯-4-醇(MHDO)的活性配位聚合制备含有双键和侧链羟基的PMHDO骨架,然后用2-氯丙酰氯处理侧链羟基得到PMHDO-Cl大分子引发剂。以PMHDO-Cl作为大分子引发剂,CuCl/Me6TREN为催化体系,在THF-H2O中进行2-(二甲基氨基)乙基甲基丙烯酸酯(DMAEMA)的单电子转移活性自由基聚合(SET-LRP)(如方案6所示),得到具有窄分子量分布的PMHDO-g-PDMAEMA接枝共聚物(Mw/Mn ≤ 1.18)(如表4所示),接枝率高达92%。荧光探针技术测定的水中的临界胶束浓度(CMC)如表4所示,透射电子显微镜初步探索聚合物胶束的形态如图4所示。
Copolymer1) t/h Convertion/%2) Mn3) Mw/Mn3) CMC4)/(g·L−1) 25a 4.0 5.33 2.10×104 1.18 5.40×10−3 25b 8.0 11.36 3.25×104 1.17 6.42×10−3 25c 12.0 14.09 3.69×104 1.16 7.00×10−3 25d 16.0 17.28 4.05×104 1.18 11.80×10−3 1)Initiated by PMHDO-Cl (Mn = 7.5×103, Mw/Mn=1.11, density of grafted SET-LRP initiating group: 82%) at 40 °C; solvent: acetone;n(DMAEA): n(Cl group): n(CuCl): n(Me6TREN) = 200∶ 1∶ 1∶ 1. 2)Obtained from 1H-NMR. 3)Measured by GPC in THF at 35 °C. 4)Determined by fluorescence spectroscopy using PNA as probe at 25 °C Wu等[23]设计合成了手性酰胺修饰的丙二烯衍生物,L-和D-N-(1-(辛基氨基)-1-氧代丙-2-基)-4-(丙-1,2-二烯-1-基氧基)-苯甲酰胺(L-31和D-31)。使用[(η3-allyl)NiOCOCF3]2/PPh3聚合L-31和D-31单体,以活性聚合方式得到具有较窄分子量分布的poly-L-31m和poly-D-31m(如方案7所示)。
研究表明这些聚合物具有稳定的螺旋构象,在非质子溶剂中测得它们的圆二色光谱(CD)以及计算机模拟均可以证明其主链具有手性(如图5所示),并探讨了在CHCl3中温度对poly-L-31100 CD的影响,结果表明在0~55 °C,该聚联烯的螺旋构象非常稳定。接着研究了溶剂对该聚联烯CD的影响,研究表明poly-L-31100在不同的非质子溶剂中显示出相似的CD光谱,在加入质子溶剂如甲醇时观察到最大吸收波长处CD值与最大吸收波长处紫外吸收之比(g)显著降低,可能是由于相邻重复单元之间的氢键相互作用减弱导致的。有意思的是,poly-L-31100还具有pH响应性,向poly-L-31100的THF溶液中加入三氟乙酸,可以将主链的螺旋结构转化为无规卷曲,再次使用三乙胺中和后又转变回螺旋构象。原子力显微镜(AFM)和扫描电子显微镜(SEM)均可看出poly-L-31100自组装的螺旋纤维形貌(如图6所示)。
图 6 (a,b) poly-L-31100自组装结构的AFM相图; (c) poly-L-31100自组装结构的SEM图片; (d)poly-L-31100在室温下氯仿溶液中的偏光显微镜图片[23]
Figure 6. (a,b) AFM phase images of the self-assembled structures of poly-L-31100; (c) SEM image of the self-assembled structure of poly-L-31100; (d) Polarized optical micrograph of poly-L-31100 in CHCl3 solution taken at room temperature[23]
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2013年,Wu等[24]开发了一种新型的联烯聚合催化体系—末端带有―Ni(dppp)Cl (dppp:1,3-双(二苯基膦基)丙烷)基团的聚噻吩。Wu等使用Ni(dppp)Cl2作为单一催化剂,通过连续单体加成,首先合成了聚噻吩,并使用一锅法合成了一系列聚(3-己基噻吩)-b-聚(十六烷氧基联烯)(P3HT-b-PHA)共聚物(方案8)。使用动力学实验证明共聚合通过受控的链增长机理进行(如图7所示),并用1H-NMR证明所得嵌段共聚物几乎全部为2,3-聚合产物(如图8所示),并且可以在溶液中自组装成球状超分子结构,在固态下显示出微相分离。
图 7 (a) 33(Mn = 9.9 × 103, Mw/Mn = 1.30)以及35(Mn = 33.5 × 103, Mw/Mn = 1.42)的SEC曲线(40 ℃,THF 为流动相);(b) 35的Mn和Mw/Mn以及35和33投料比的关系(Mn = 7.0 × 103, Mw/Mn = 1.22)[24]
Figure 7. (a) Size exclusion chromatograms of 33 (Mn = 9.9 × 103, Mw/Mn = 1.30) and its respective 35 (Mn = 33.5 × 103, Mw/Mn = 1.42)(40 ℃, THF as an eluent); (b) Plots of Mn and Mw/Mn of 35 measured as a function of the feed ratio of 35 to 33 (Mn = 7.0 × 103, Mw/Mn = 1.22)[24]
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由于聚噻吩催化体系聚合联烯可以得到白光材料、荧光材料以及在自组装方面的应用而受到广泛的关注[25-32]。2014年,Wu等[25]使用π-烯丙基镍配合物引发噻吩聚合,得到具有烯丙基末端的区域规整性聚(3-己基噻吩),其链末端的镍仍具有聚合活性,可引发十六烷氧基联烯嵌段共聚,其链末端镍可继续引发噻吩聚合,得到三嵌段共聚物(方案9),并证明该聚合反应以可控活性方式进行,且产率较高(表5)。
Run P3HT (poly-b39m) P3HT-b-PHA (poly(b39m-b-40n)) P3HT-b-PHA-b-P3HT (poly(b39m-b-40n-b-39o)) Yield/% m∶n∶o Mn Mw/Mn Mn Mw/Mn Mn Mw/Mn 1 6.31 × 103 1.15 11.3 × 103 1.19 17.6 × 103 1.25 78 40∶40∶40 2 7.18 × 103 1.16 19.6 × 103 1.25 31.2 × 103 1.27 80 45∶100∶70 3 9.74 × 103 1.19 12.2 × 103 1.27 18.6 × 103 1.30 77 60∶20∶40 4 7.69 × 103 1.17 10.7 × 103 1.19 12.5 × 103 1.27 76 50∶30∶10 Wu等[6]在2015年对聚噻吩催化联烯活性聚合及在自组装和白光材料方面的应用进行了探究。报道了一系列含有聚(3-己基噻吩)(P3HT)和聚(三乙氧基联烯)(PTA)链段的新型嵌段共聚物,使用镍配合物作为单一催化剂,通过不同的聚合机理使用一锅法合成(方案10),并通过动力学实验证明其为可控活性聚合。有趣的是,P3HT-b-PTA二嵌段共聚物在水中表现出优异的热响应性,其低临界溶解温度(LCST)取决于聚合物浓度和嵌段比。此外,P3HT-b-PTA 在CHCl3中显示出pH响应性质,在交替添加三氟乙酸和三乙胺时,发光颜色在橙色和深绿色之间变化。P3HT-b-PTA和P3HT-b-PTA-b-P3HT均表现出溶剂化变色性质。通过溶剂的变化可以轻松调节嵌段共聚物的发射光颜色,其发射光颜色从红色到蓝色广泛地跨越(如图9(a)、图9(b)所示)。此外,在THF-甲醇混合溶液中(THF与甲醇的体积比为1∶ 3),P3HT-b-PTA-b-P3HT可以轻松地实现白光发射。Wu等[26]在2017年合成了含有疏水性P3HT,亲水性聚(三甘醇丙二烯)和带有三乙二醇单甲醚链的亲水性聚异腈的两亲性三嵌段共聚物。这种两亲性三嵌段共聚物表现出可调节的光发射性能,其响应于各种环境刺激,如溶剂、pH和温度。值得注意的是,这种两亲性三嵌段共聚物在溶液、凝胶和固态下均易实现白光发射。
图 9 (a)poly(4135-b-4265)在THF、甲醇和水中的照片 (ρ = 0.5 g/L);(b) poly(4135-b-4265)在THF、甲醇和水中的归一化紫外吸收光谱(ρ = 0.15 g/L);(c) poly(4135-b-4265)在THF、甲醇和水中于25 °C (ρ = 0.5 g/L), 365 nm紫外光下的照片;(d) poly(4135-b-4265)在THF、甲醇和水中于25 °C (ρ = 0.15 g/L), 380 nm的发射光谱[6]
Figure 9. (a) Photographs of poly(4135-b-4265) in THF, methanol and water (ρ = 0.5 g/L); (b) Normalized absorption spectra of poly(4135-b-4265) in THF, methanol and water (ρ = 0.15 g/L); (c) Photographs of poly(4135-b-4265) in THF, methanol and water under UV light at 365 nm at 25 °C (ρ = 0.15 g/L); (d) Normalized emission spectra of poly(4135-b-4265) in THF, methanol, and water at 25 °C with excitation at 380 nm (ρ = 0.15 g/L) [6]
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目前π-烯丙基镍催化体系催化聚合联烯因具有活性可控、分子量分布窄、单体适用范围广、可实现联烯与其他单体嵌段共聚且能自组装成不同形貌等优点,因此得到了广泛运用。相比较于π-烯丙基镍催化体系聚合联烯时的聚合选择性不高,往往包含1,2-和2,3-聚合的2种产物,聚噻吩催化体系聚合联烯时2,3-聚合产物占绝大部分,且为活性聚合,并可通过制备两亲性嵌段共聚物使其具有自组装性能。此外,通过聚噻吩催化联烯聚合还可制备白光材料,但不足的是生成的聚合物分子量分布稍宽。因此,发展高选择性2,3-聚合、分子量分布窄、且聚合活性可控的聚联烯的催化体系仍是化学工作者研究工作的重点之一。
镍配合物催化联烯活性聚合的研究进展
Research Progress on Living Polymerization of Allenes Catalyzed by Nickel Complexes
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摘要: 联烯因具有1,2-累积双键的独特结构,可表现出特殊的反应活性,在适当的条件下能选择性地进行1,2-或2,3-位聚合。末端连有不同取代基的联烯,聚合后连于主链的双键可进一步与其他功能基团反应,从而获得新的功能性材料。本文主要介绍了烯丙基镍配合物及聚3-己基噻吩(P3HT)两种催化体系聚合联烯的方法,并讨论了镍配合物聚合联烯时单体上的取代基、反应溶剂对聚合的影响,不同镍配合物催化剂在催化联烯活性聚合方面的应用及聚噻吩体系聚合联烯获得的聚合物的各种组装性能,以及使用烯丙基镍催化体系聚合手性联烯单体获得具有稳定结构的光学活性聚联烯等内容。Abstract: Allene derivatives have cumulated double bonds and can be regarded as the isomers of propargyl derivatives. Due to their unique structures with 1,2-cumulative double bonds, they can exhibit special reactivity and can selectively conduct 1,2- or 2,3-position polymerization under appropriate conditions. Taking advantage of this characteristic, polymers with exomethylene substituents can be obtained through the selective polymerization of either part (1,2- or 2,3-)of the cumulated double bonds. Allylnickel( II)complexes and poly( 3-hexylthiophene)( P3HT)have been reported to promote the living/controlled polymerization of allene derivatives. The polymerization of allene using the catalysts such as allylnickel( II)complexes and poly( 3-hexylthiophene)( P3HT)is presented with detailed discussion, including the impact of the substituents on the monomers, the reaction solvent during the polymerization using allylnickel( II)complexes as catalyst, the application of living polymerization of allene using different allylnickel( II)complexes, and the self-assembly performance of polyallenes using P3HT as catalyst. In addition, living polymerizations of chiral allene monomers with allylnickel complex as a catalyst afforded helical polyallenes was also described. The helical structure of the polyallenes was quite stable with a preferred handedness in aprotic solvents. The helical polyalkenes behaved pH-responsive property due to the amino group on the pendant.
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Key words:
- allenes /
- nickel complex /
- polythiophene /
- living polymerization
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图 6 (a,b) poly-L-31100自组装结构的AFM相图; (c) poly-L-31100自组装结构的SEM图片; (d)poly-L-31100在室温下氯仿溶液中的偏光显微镜图片[23]
Figure 6. (a,b) AFM phase images of the self-assembled structures of poly-L-31100; (c) SEM image of the self-assembled structure of poly-L-31100; (d) Polarized optical micrograph of poly-L-31100 in CHCl3 solution taken at room temperature[23]
图 7 (a) 33(Mn = 9.9 × 103, Mw/Mn = 1.30)以及35(Mn = 33.5 × 103, Mw/Mn = 1.42)的SEC曲线(40 ℃,THF 为流动相);(b) 35的Mn和Mw/Mn以及35和33投料比的关系(Mn = 7.0 × 103, Mw/Mn = 1.22)[24]
Figure 7. (a) Size exclusion chromatograms of 33 (Mn = 9.9 × 103, Mw/Mn = 1.30) and its respective 35 (Mn = 33.5 × 103, Mw/Mn = 1.42)(40 ℃, THF as an eluent); (b) Plots of Mn and Mw/Mn of 35 measured as a function of the feed ratio of 35 to 33 (Mn = 7.0 × 103, Mw/Mn = 1.22)[24]
图 9 (a)poly(4135-b-4265)在THF、甲醇和水中的照片 (ρ = 0.5 g/L);(b) poly(4135-b-4265)在THF、甲醇和水中的归一化紫外吸收光谱(ρ = 0.15 g/L);(c) poly(4135-b-4265)在THF、甲醇和水中于25 °C (ρ = 0.5 g/L), 365 nm紫外光下的照片;(d) poly(4135-b-4265)在THF、甲醇和水中于25 °C (ρ = 0.15 g/L), 380 nm的发射光谱[6]
Figure 9. (a) Photographs of poly(4135-b-4265) in THF, methanol and water (ρ = 0.5 g/L); (b) Normalized absorption spectra of poly(4135-b-4265) in THF, methanol and water (ρ = 0.15 g/L); (c) Photographs of poly(4135-b-4265) in THF, methanol and water under UV light at 365 nm at 25 °C (ρ = 0.15 g/L); (d) Normalized emission spectra of poly(4135-b-4265) in THF, methanol, and water at 25 °C with excitation at 380 nm (ρ = 0.15 g/L) [6]
表 1 使用[(η3-allyl)NiX]2 催化剂聚合联烯的表征数据[15]
Table 1. Polymerization of allenes by transition metal catalysts[15]
Expt. No.1) Catalyst cMonomer/(mol·L−1) Solvent2) T/ ℃ t/h Yield/% $ { { { {M_{\rm n}^{3 )} } } } }$ Complex c/(mmol·L−1) A-8 (π-C8H12)2Ni 2 2 Benzene 40 24 67.5 … A-30 (π-C8H12)2Ni 2 2 Benzene 7 48 18.0 … A-31 (π-C8H12)2Ni 2 2 Benzene 0 48 0 … A-111 (π-C3H5NiBr)2 2 1 Benzene 15 24 92.5 … A-98 (π-C3H5NiBr)2 8.4 2.7 Toluene 40 1 46.4 1.07×105 A-116 (π-C3H5NiBr)2 8.4 2.6 Toluene 0 20.5 85.0 1.38×106 A-15 Ni(acac)24)-AlEt3 25) 2 Benzene 40 24 16.26) … A-117 Ni(acac)2 2 2 Benzene 40 24 0 … A-118 (PPh3)2NiBr2 2 2 Benzene 40 24 0 … 1)Polymerization was carried out under purified nitrogen and the polymer was isolated as usual. As an antioxidant for the polymer 2, 2'-methylenebis(4-methyl-6-t-butylphenol) was used. 2)Solvents were deoxygenated and the water content was kept below 10 μg/mL. In toluene a comparable yield of the polymer having the same microstructure was obtained as in benzene, but the yield was lower in n-hexane and diethyl ether than in benzene. 3)The number average molecular weight was measured by a membrane osmometer (Mechrolab Inc., Model 502). 4)acac=acetylacetonate. 5)This is the concentration of Ni(acac)2 and the mole ratio of AlEt3/Ni(acac)2 is 2. 6)The polymer was insoluble in benzene. Run Monomer Solvents kobs/(L·mol−1·h−1) Yield/% x∶y Mn Mw/Mn 1 20 Toluene 0 0 2 20 DMSO/toluene1) 2.6 49 27∶73 3.2×103 1.03 3 20 EtOH/toluene1) 16.4 99 28∶72 8.6×103 1.07 4 20 Pyrrole/toluene1) 62.2 99 31∶69 7.1×103 1.08 5 20 Indole/toluene1) 86.9 94 31∶69 7.6×103 1.08 6 20 Phenol/toluene1) 224.0 93 49∶51 7.6×103 1.08 7 21 Toluene 0 0 8 21 Pyrrole 6.2 98 0 5.6×103 1.05 1)Volume ratio is 1 表 3 使用[(η3-allyl)NiOCOCF3]2/PPh3体系催化丙二烯基醚配位聚合[20]
Table 3. Coordination polymerization of allenyl ethers catalyzed by [(η3-allyl)NiOCOCF3]2/PPh3 system[20]
Run M cM/cI Yield/% x∶y Mn Mw/Mn 1 a 65 91 70∶30 8 290 1.06 2 b 50 93 70∶30 7 670 1.08 3 c 49 84 70∶30 5 870 1.11 4 d 52 92 80∶20 5 990 1.13 5 e 50 82 70∶30 6 050 1.11 6 f 51 88 80∶10 5 590 1.13 7 100 100 90∶10 9 880 1.08 Copolymer1) t/h Convertion/%2) Mn3) Mw/Mn3) CMC4)/(g·L−1) 25a 4.0 5.33 2.10×104 1.18 5.40×10−3 25b 8.0 11.36 3.25×104 1.17 6.42×10−3 25c 12.0 14.09 3.69×104 1.16 7.00×10−3 25d 16.0 17.28 4.05×104 1.18 11.80×10−3 1)Initiated by PMHDO-Cl (Mn = 7.5×103, Mw/Mn=1.11, density of grafted SET-LRP initiating group: 82%) at 40 °C; solvent: acetone;n(DMAEA): n(Cl group): n(CuCl): n(Me6TREN) = 200∶ 1∶ 1∶ 1. 2)Obtained from 1H-NMR. 3)Measured by GPC in THF at 35 °C. 4)Determined by fluorescence spectroscopy using PNA as probe at 25 °C 表 5 P3HT,P3HT-b-PHA和P3HT-b-PHA-b-P3HT的聚合结果[25]
Table 5. Polymerization results of P3HT, P3HT-b-PHA, and P3HT-b-PHA-b-P3HT[25]
Run P3HT (poly-b39m) P3HT-b-PHA (poly(b39m-b-40n)) P3HT-b-PHA-b-P3HT (poly(b39m-b-40n-b-39o)) Yield/% m∶n∶o Mn Mw/Mn Mn Mw/Mn Mn Mw/Mn 1 6.31 × 103 1.15 11.3 × 103 1.19 17.6 × 103 1.25 78 40∶40∶40 2 7.18 × 103 1.16 19.6 × 103 1.25 31.2 × 103 1.27 80 45∶100∶70 3 9.74 × 103 1.19 12.2 × 103 1.27 18.6 × 103 1.30 77 60∶20∶40 4 7.69 × 103 1.17 10.7 × 103 1.19 12.5 × 103 1.27 76 50∶30∶10 -
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