Novel Macrocyclic Oligomers Consisting of Triphenylamine and Oligofluorenes

Significance

The authors designed and synthesized two novel multi-H shaped macrocyclic oligomers 1 and 2 consisting of triphenylamine and oligofluorene by combining the advantages of triphenylamine moieties for suppressing the green emission of polyfluorenes. The key step in the synthesis is the cyclization under acid condition to afford cyclic trimers that possess 6 sp³ hybridized atoms. Compound 3 was reacted with n-BuLi in THF, followed by the addition of 2,7-dibromofluorene to give 4, which was reacted with boronic acid derivatives using a Suzuki coupling to afford 5 and 6. The final cyclization was a self-condensation reaction of the monomers using a catalytic amount of methylsulfonic acid to give the cyclic trimers 1 and 2 in excellent yields.