Conjugated Hybrid Organosilicon Polymers from Low-Valent Silicon Precursors

我们建议在双功能低价硅前驱体与不同类型的双官能团共轭有机连接单元共聚的基础上合成含硅杂化聚合物。尽管作为有机半导体和光刻胶的潜在应用广泛，但缺乏通用、高产(原子经济)和选择性的合成方法严重限制了共轭硅基聚合物的发展。我们的初步结果表明，在聚合物合成中使用无催化剂的温和反应条件，将允许采用高度模块化的方法来合成此类聚合物。使用稳定的双功能低价硅前驱体的无副产物协议将产生前所未有的产率和选择性。将访问三种不同的一般类型的聚合物：(A)具有交替的二硅烷型和苯型重复单元的聚合物，(B)具有作为重复单元的新的同/杂环硅烷基元的聚合物，其包含外环不饱和硅部分，以及(C)具有交叉共轭不饱和硅键的聚合物。在(B)和(C)的情况下，预期通过高活性的Si=C和Si=Si单元容易地进行后聚合官能化。因此，各种基于硅基的重复单元(二硅环丁烯、硅氮杂环丁、氮杂/磷硅烷、环三硅烷、三硅环戊二烯)将以交替的方式与pi共轭的有机连接物一起用于聚合物主干中。我们可以使用的各种共轭途径(例如，sigma-pi重叠、沃尔什轨道、交叉超共轭等)。这无疑会影响材料的光电性能和机械性能。我们关于有机和不饱和硅共聚单体的模块化概念将为推断聚合物的所有一级、二级和(最终)三级结构的结构-性质关系提供有价值的数据。

We propose to synthesize conjugated silicon-containing hybrid polymers on the basis of the co-polymerization of difunctional low-valent silicon precursors with various - likewise difunctional - conjugated organic linking units.Despite various potential applications (e.g. as organic semiconductors and photoresists), the lack of versatile, high-yielding (atom-economic) and selective synthetic methods has limited the development of conjugated silicon-based polymers severely. The use of catalyst-free milder reaction conditions for polymer synthesis, as is evidenced in our preliminary results, will allow for a highly modular approach to such polymers. Byproduct-free protocols using stable difunctional low-valent silicon precursors will give rise to unprecedented yields and selectivities. Three different general types of polymers will be accessed: (A) polymers with alternating disilanylene and phenylene-type repeat units, (B) polymers with novel homo/hetero-cyclic silane motifs as repeat units that incorporate exocyclic unsaturated silicon moieties, and (C) polymers with cross-conjugated unsaturated silicon bonds. In the cases of (B) and (C) facile post-polymerization functionalization via the highly reactive Si=C and Si=Si units is anticipated.A variety of silicon-based repeat units (disilacyclobutene, silaaziridine, aza/phosphasilirene, cyclotrisilane, trisilacyclopentadiene) will thus be employed in the polymer backbone in alternating fashion with pi-conjugated organic linkers. The various conjugative pathways at our disposal (e.g. sigma-pi overlap, Walsh orbitals, cross-hyperconjugation etc.) will undoubtedly influence the optoelectronic and mechanical properties of the materials. The modularity of our concept with regards to both the organic and the unsaturated silicon co-monomers will furnish valuable data for the deduction of structure-property relationships in all of primary, secondary and (ultimately) tertiary structure of the polymers.