Synthesis and characterization of oligothiophene-modified spirobifluorene

A series of novel 9,9' - spirobifluorenes functionalized by non - substitut ed oligothiophenes were synthesized through a coupling reaction between the oligothienyl - zinc chloride and the brominated spirobifluorene. The core is a 9,9' - spirobifluorene and all the branching anus are affixed to the c ore in a single operation, which makes the syntheses highly convergent. The tetrahedral bonding atom at the center of a spiro - annulated molecule mai ntains 90 degrees angle between the connected conjugated moieties via a Q - bonded network, which is useful to modify the steric demand of small molec ular compounds to improve their processibility and morphologic stability, w ith their electronic properties maintained. Contrary to the non substituted a - oligo-thiophenes, which naturally intend to crystallize, the oligothio phene modified 9, 9' spirobifluorenes were found to readily form amorphous glasses at ambient temperature and to exhibit high morphological stability with high glass transition temperatures ranging from 101 degreesC to 186 de greesC. This series of materials also kept the good properties of oligothio phenes, such as the easy accessibility through various synthetic methodolog ies, good chemical and thermal stability, as well as the tunable energy lev els and the emission color.