Abstract

Previously, it was shown that the presence of bulky silicon-containing substituents in the monomer unit of metathesis polynorbornenes hinders the postmodification and, in particular, exhaustive gem-difluorocyclopropanation of main-chain double bonds. In order to reduce the double bonds shielding by substituents, a new polynorbornene with a dimethylsilacyclopentane fragment in the monomer unit, poly(4,4-dimethyltricyclo[5.2.1.0^2,6]-4-siladec-8-ene) (PNBCP), is synthesized, in which the silylmethyl group is moved further from the double bonds. In order to achieve this, the monomer 4,4-dimethyltricyclo[5.2.1.0^2,6]-4-siladec-8-ene (NBCP) is first obtained via the diene condensation of 1,3-cyclopentadiene and 1,1-dichlorosilacyclopent-3-ene with following methylation of Si-Cl bonds. NBCP is polymerized by the ring-opening metathesis scheme in the presence of the first-generation Grubbs catalyst, Cl₂(PCy₃)₂Ru=CHPh. The new polymer PNBCP is obtained in a yield of 99–100% and characterized. The gem-difluorocyclopropanation of PNBCP with difluorocarbene, generated during the thermolysis of sodium chlorofluoroacetate, is studied; the conditions for exhaustive replacement of double bonds by gem-difluorocyclopropane are found. It is shown that PNBCP is more active in postmodification compared to poly(5-trimethylsilyl)norbornene but is less active than unsubstituted polynorbornene. It is demonstrated that the introduction of the silacyclopentane fragment into the monomer unit of the metathesis polynorbornene and its subsequent difluorocyclopropanation lead to increase in gas permeability and diffusion and cause a slight decrease in ideal separation selectivities. It is found that gem-difluorocyclopropanation increases the glass transition temperature of PNBCP by 60°C and makes its films stable when stored in air.

中文翻译：

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新型含硅环戊烷的聚降冰片烯的合成及气体分离性能

抽象的

先前已表明，在复分解聚降冰片烯的单体单元中存在大量的含硅取代基会阻碍后修饰，特别是阻碍主链双键的宝石-二氟环丙烷化。为了减少取代基对双键的屏蔽作用，一种新的聚降冰片烯在单体单元中带有一个二甲基硅环戊烷片段，聚（4,4-二甲基三环[5.2.1.0 ^2,6 ] -4-siladec-8-ene）（PNBCP）合成了其中的甲硅烷基甲基，其中甲硅烷基甲基离双键更远。为了实现这一点，单体4,4-二甲基三环[5.2.1.0 ^2,6首先通过1，3-环戊二烯和1，1-二氯硅环戊-3-烯的二烯缩合，然后使Si-Cl键甲基化，获得] -4-siladec-8-ene（NBCP）。在第一代Grubbs催化剂Cl ₂（PCy ₃）₂ Ru = CHPh的存在下，NBCP通过开环复分解方案进行聚合。以99–100％的收率获得了新型聚合物PNBCP，并进行了表征。所述宝石PNBCP的-difluorocyclopropanation与二氟卡宾，chlorofluoroacetate钠的热解过程中产生的，进行了研究; 用宝石彻底取代双键的条件发现了-二氟环丙烷。结果表明，与聚（5-三甲基甲硅烷基）降冰片烯相比，PNBCP在后改性中活性更高，但比未取代的聚降冰片烯活性低。已证明将硅杂环戊烷片段引入复分解的聚降冰片烯的单体单元中及其随后的二氟环丙烷化会导致气体渗透性和扩散增加，并导致理想的分离选择性略有下降。发现宝石-二氟环丙烷化将PNBCP的玻璃化转变温度提高了60°C，并使其在空气中储存时的膜稳定。