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

作者：Sun, Huiliang; Zhang, Shuren; Yang, Yike; Li, Xiao; Zhan, Hongmei; Cheng, Yanxiang

来源：Macromolecular Chemistry and Physics, 2016, 217(24): 2726-2735.

DOI：10.1002/macp.201600412

• CHAIN-GROWTH POLYMERIZATION
• CROSS-COUPLING POLYMERIZATION
• DEFINED CONJUGATED POLYMERS
• AB-TYPE MONOMERS
• TRANSFER POLYCONDENSATION
• HYPERBRANCHED POLYMERS
• ORGANIC PHOTOVOLTAICS
• OXIDATIVE ADDITION
• MOLECULAR-WEIGHT
• KUMADA CATALYST

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(PCy3)(2) (PCy3 = 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 PCy3. 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 Pd4Pd6-catalyzed SCTP bear precisely the Ar group on one chain end and 4-tert-butylphenyl endcapping 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.