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A systematic study of stereochemical effects in homologous poly(alkenamer)s: Dewar benzene versus norbornene
Journal of Polymer Science ( IF 3.9 ) Pub Date : 2020-05-26 , DOI: 10.1002/pol.20200250 Stanfield Y. Lee 1 , Jinwon Seo 1 , Christopher W. Bielawski 1, 2, 3
Journal of Polymer Science ( IF 3.9 ) Pub Date : 2020-05-26 , DOI: 10.1002/pol.20200250 Stanfield Y. Lee 1 , Jinwon Seo 1 , Christopher W. Bielawski 1, 2, 3
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Two diastereomeric derivatives of norbornene, dimethyl (1R,2R,3S,4S)‐bicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylate and dimethyl (1R,2S,3S,4S)‐bicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylate, were synthesized and polymerized using ring‐opening metathesis polymerization (ROMP). For comparative purposes, diastereomeric derivatives of Dewar benzene, dimethyl (1R,2S,3R,4S)‐bicyclo[2.2.0]hex‐5‐ene‐2,3‐dicarboxylate and dimethyl (1R,2S,3S,4S)‐bicyclo[2.2.0]hex‐5‐ene‐2,3‐dicarboxylate, were also synthesized and polymerized using ROMP. The polymerization reactions proceeded in a controlled manner as evidenced in part by linear relationships between the monomer‐to‐catalyst feed ratios and the molecular weights of the polymer products. Chain extension experiments were also conducted which facilitated the formation of block copolymers. Although the poly(norbornene) derivatives exhibited glass transition temperatures that were dependent on their monomer stereochemistry (cis: 115°C vs. trans: 125°C), more pronounced differences were observed upon analysis of the polymers derived from Dewar benzene (cis: 70°C vs. trans: 95°C). Likewise, microphase separation was observed in block copolymers that were prepared using the diastereomeric monomers derived from Dewar benzene but not in block copolymers of the norbornene‐based diastereomers. The differential thermal properties were attributed to the relative monomer sizes as reducing the distances between the polymer backbones and the pendant stereocenters appeared to enhance the thermal effects.
中文翻译：
对同源聚（链烯单体）中立体化学作用的系统研究：杜瓦瓶苯与降冰片烯
降冰片烯的两个非对映异构体衍生物，二甲基（1R，2R，3S，4S）-双环[2.2.1]庚-5-烯-2,3-二羧酸酯和二甲基（1R，2S，3S，4S）-双环[2.2。使用开环复分解聚合（ROMP）合成和聚合1] -5-烯-2,3-二羧酸庚酯。为了比较目的，杜瓦苯，二甲基（1R，2S，3R，4S）-双环[2.2.0] hex-5-烯-2,3-二羧酸酯和二甲基（1R，2S，3S，4S）-的非对映异构体衍生物还使用ROMP合成并聚合了双环[2.2.0] hex-5-烯-2,3-二羧酸酯。聚合反应以受控的方式进行，部分通过单体与催化剂的进料比与聚合物产物的分子量之间的线性关系证明。还进行了扩链实验，以促进嵌段共聚物的形成。顺式：115°C，反式：125°C），分析杜瓦苯衍生的聚合物时观察到更明显的差异（顺式：70°C，反式：95°C）。同样，在使用衍生自杜瓦苯的非对映异构单体制备的嵌段共聚物中观察到微相分离，但在降冰片烯基非对映异构体的嵌段共聚物中未观察到微相分离。不同的热性能归因于相对单体尺寸，因为减小聚合物主链和侧链立体中心之间的距离似乎增强了热效应。
更新日期：2020-05-26
中文翻译：
对同源聚（链烯单体）中立体化学作用的系统研究：杜瓦瓶苯与降冰片烯
降冰片烯的两个非对映异构体衍生物，二甲基（1R，2R，3S，4S）-双环[2.2.1]庚-5-烯-2,3-二羧酸酯和二甲基（1R，2S，3S，4S）-双环[2.2。使用开环复分解聚合（ROMP）合成和聚合1] -5-烯-2,3-二羧酸庚酯。为了比较目的，杜瓦苯，二甲基（1R，2S，3R，4S）-双环[2.2.0] hex-5-烯-2,3-二羧酸酯和二甲基（1R，2S，3S，4S）-的非对映异构体衍生物还使用ROMP合成并聚合了双环[2.2.0] hex-5-烯-2,3-二羧酸酯。聚合反应以受控的方式进行，部分通过单体与催化剂的进料比与聚合物产物的分子量之间的线性关系证明。还进行了扩链实验，以促进嵌段共聚物的形成。顺式：115°C，反式：125°C），分析杜瓦苯衍生的聚合物时观察到更明显的差异（顺式：70°C，反式：95°C）。同样，在使用衍生自杜瓦苯的非对映异构单体制备的嵌段共聚物中观察到微相分离，但在降冰片烯基非对映异构体的嵌段共聚物中未观察到微相分离。不同的热性能归因于相对单体尺寸，因为减小聚合物主链和侧链立体中心之间的距离似乎增强了热效应。
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