Excellent Control of Perylene Diimide End Group in Polyfluorene via Suzuki Catalyst Transfer Polymerization

Six aryl Pd(II) bromide complexes based on perylene diimide derivative (Ar) and phosphine mixed‐ligands are successfully synthesized by directly oxidative addition of Ar–Br to the Pd(0) precursor. These complexes with the general formulas ArPdBr(PCy 3 ) 2 (PCy 3 = tricyclohexylphosphine; Pd1–Pd3 ) and [ArPdBr(TXP‐2,4)] 2 (TXP‐2,4 = tri‐2,4‐xylylphosphine; Pd4–Pd6 ) are stable and can be handled in air at room temperature. By employing the Pd(II) complexes as initiators, Suzuki catalyst transfer polymerization (SCTP) of AB‐type fluorene monomer is investigated for preparing polyfluorenes (PFs) with the defined end group. Complexes Pd4–Pd6 with auxiliary TXP‐2,4 ligand can initiate polymerization of AB‐type fluorene monomer at room temperature, while higher polymerization temperature is required for Pd1–Pd3 with alkyl phosphine PCy 3 . The obtained polymers are analyzed by matrix‐assisted laser desorption ionization‐time‐of‐flight mass spectrometry, which confirms that the Ar group is appended to the terminus of the polymer chain. Moreover, PFs prepared by Pd4–Pd6 ‐catalyzed SCTP bear precisely the Ar group on one chain end and 4‐ tert ‐butylphenyl end‐capping group on the opposite end, which indicates that Pd4–Pd6 with the bulky TXP‐2,4 exhibit better catalytic performance in SCTP. Photoluminescence spectra of the obtained polymers show a dual or a blue emission resulting from the difference of the molecular weight.