Stereospecific Ring-Opening Metathesis Polymerization (ROMP) of endo-Dicyclopentadiene by Molybdenum and Tungsten Catalysts
Stereospecific Ring-Opening Metathesis Polymerization (ROMP) of endo-Dicyclopentadiene by Molybdenum and Tungsten Catalysts
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DOI：
10.1021/acs.macromol.5b00123
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发表时间：
2015-04-28
期刊：
影响因子：
5.5
通讯作者：
Schrock, Richard R.
中科院分区：
文献类型：
--
作者：
Autenrieth, Benjamin;Jeong, Hyangsoo;Schrock, Richard R.
研究了10种常用的铼系和16种钨系烷叉基引发剂引发的双环戊二烯开环易位聚合反应。五钨基MAP具有通式W（X）的（单芳氧吡咯烷）引发剂（CHCMe2Ph）（Me（2）Pyr）（OAr）（X =芳基亚氨基、烷基亚氨基或氧代; Me（2）Pyr = 2，5-二甲基吡咯烷; OAr =芳氧化物）的顺式聚（DCPD）和间同立构聚（DCPD）的产率分别为>98%和>98%;它们是W（N-t-Bu）（CHCMe 3）（pyr）（OHMT）（2，OHMT = O-2，6-（2，4，6-Me 3C 6 H2）（2）C6 H3，pyr =吡咯烷），W（N-2，6-i-Pr2C6H3）（CHCMe2Ph）（pyr）（OHMT）（3），W（O）（CHCMe2Ph）（Me（2）Pyr）（OHMT）（PPh2Me）（7，Me 2 Pyr = 2，5-二甲基吡咯烷），W（O）（CHCMe2Ph）（Me（2）Pyr）（ODFT）（PPh2Me）（9，ODFT = O-2，6-（C6F5）（2）C6H3）和W（O）（CHCMe2Ph）（Me（2）Pyr）（OTPP）（PMePh2）（10，OTPP = O-2，3，5，6-Ph4C6H）。发现两种联酚烷叉配合物Mo（N-2，6-Me_2C_6H_3）（CHCMe_2Ph）（rac-biphen）（17）和W（N-2，6-Me_2C_6H_3）（CHCMe_2Ph）（rac-biphen）（2,2，biphen = 3，3 ′-（t-Bu）（2）-5，5 ′-6，6 ′-（CH_3）4- 1，1 ′-联苯-2，2 ′-二醇盐）的顺式聚（DCPD）产率>98%，全同立构聚（DCPD）产率> 98%。顺式、间同立构或顺式、全同立构聚（DCPD）（用50-1000当量的DCPD制备）在室温下在二氯甲烷中在数秒至数分钟内可获得。没有观察到异构化或交联反应，并且添加链转移试剂（1-己烯）或使用THF作为溶剂不会降低聚合的立体定向性。顺式、间同立构和顺式、全同立构聚（DCPD）可以通过C-13 NMR光谱容易地彼此区分。每种有规立构聚（DCPD）的氢化产生H-聚（DCPD），其具有接近270 ° C（间同立构）或290 ° C（全同立构）的熔点和高堆积度（对于间同立构，w（c）= 0.83，对于全同立构，wc = 0.74）。
We report an examination of the ring-opening metathesis polymerization (ROMP) of endo-dicyclopentadiene (DCPD) by 10 well-defined molybdenum-based and 16 tungsten-based alkylidene initiators. Five tungsten-based MAP (monoaryloxide pyrrolide) initiators with the general formula W(X)(CHCMe2Ph)(Me(2)Pyr)(OAr) (X = arylimido, alkylimido, or oxo; Me(2)Pyr =2,5-dimethylpyrrolide; OAr = an aryloxide) were found to yield >98% cis, >98% syndiotactic poly(DCPD); they are W(N-t-Bu)(CHCMe3)(pyr)(OHMT) (2, OHMT = O-2,6-(2,4,6-Me3C6H2)(2)C6H3, pyr = pyrrolide), W(N-2,6-i-Pr2C6H3)(CHCMe2Ph)(pyr)(OHMT) (3), W(O)(CHCMe2Ph)(Me(2)Pyr)(OHMT)(PPh2Me) (7, Me2Pyr =2,5-dimethylpyrrolide), W(O)(CHCMe2Ph)(Me(2)Pyr)(ODFT)(PPh2Me) (9, ODFT = O-2,6-(C6F5)(2)C6H3), and W(O)(CHCMe2Ph)(Me(2)Pyr)(OTPP)(PMePh2) (10, OTPP = O-2,3,5,6-Ph4C6H). Two biphenolate alkylidene complexes, Mo(N-2,6-Me2C6H3)(CHCMe2Ph)(rac-biphen) (17) and W(N-2,6-Me2C6H3)(CHCMe2Ph)(rac-biphen) (22, biphen =3,3'-(t-Bu)(2)-5,5'-6,6'-(CH3)4-1,1'-biphenyl-2,2'-diolate), were found to yield >98% cis, >98% isotactic poly(DCPD). Cis, syndiotactic or cis, isotactic poly(DCPD)s (made with 50-1000 equiv of DCPD) are accessible within seconds to minutes in dichloromethane at room temperature. No isomerization or cross-linking reactions are observed, and addition of a chain transfer reagent (1-hexene) or the use of THF as a solvent does not decrease the stereospecificity of the polymerizations. Cis, syndiotactic and cis, isotactic poly(DCPD)s can be distinguished readily from each other by C-13 NMR spectroscopy. Hydrogenation of each stereoregular poly(DCPD) produces H-poly(DCPD)s that have melting points near 270 degrees C (syndiotactic) or 290 degrees C (isotactic) and high crystallinities (w(c) = 0.83 for syndiotactic and wc = 0.74 for isotactic).