New Synthetic Strategies for Semiconducting Polymers : Incorporation of Tin, Boron and Gold as Metalfunctionalities and Dinucleophile Synthesis

In this thesis a general method for the synthesis of dinucleophilic compounds, containing both a stannyl and a boron moiety, was developed. Using a thiophene derivative as dinucleophile, it was possible to show that a both nucleophile and electrophile selective cross-coupling reaction could be performed successfully. This type of reaction allows the combination of different aromatic systems, where the products still contain both a halogen and a boron functionality. It was shown for electron poor, rich and neutral dielectrophiles that this reaction can be used as a general method. The resulting products can be used, besides other potential applications, as monomers in polymerization reactions and thus for the synthesis of semiconducting polymers. Furthermore the first compound of another class of dinculeophiles could be successfully synthesized: A thiophene derivative which contains both a boron and a gold moiety as metal functional groups. Organogold reagents have been rarely used in stoichiometric amounts so far. It was shown that these compounds perform cross-coupling reactions under mild reaction conditions and in high yields. Therefore this type of both gold and boron functionalized dinucleophiles are suitable for a potential use in dually-selective cross-coupling reactions. The synthesis of well-defined regio regular poly(3-hexylthiophene) (P3HT) is generally performed by using the method of living polymerization. Monomers for these reactions generally contain both a halogen and a metal functionality. Until now the synthesis of monomers that are stable and can be isolated before use is a problem. Therefore a monomer was synthesized, which was comprised of two hexylthiophene units and which contained gold moiety as functional groups as well as a bromide as electrophile functionality. This monomer was stable to air and moisture. A catalyst screening of the polymerization reaction gave two different polymers as products, depending on the catalyst species used. Both polymers showed high regio regularities but were considerably different from each other: On the one hand HH-TT-P3HT was obtained, on the other hand the expected HT-P3HT could be isolated (HH = Head-to-Head, TT = Tail-to-Tail, HT = Head-to-Tail). These successful polymerization reactions gave new insights and findings especially on cross-coupling reactions of organogold reagents.