Conjugated Hybrid Organosilicon Polymers from Low-Valent Silicon Precursors

• Applicant: Professor Dr. David Scheschkewitz
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation ; Polymer Materials
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 248841933

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.

• DFG Programme: Research Grants
• International Connection: United Kingdom
• Participating Person: Professor Dr. Ian Manners (†)