Macromolecules, Vol.51, No.21, 9043-9051, 2018
Controlled Polymerization of a Cyclopentadithiophene-Phenylene Alternating Copolymer
The new conjugated poly(4,4-bis(2-ethylhexyl)-cyclopentadithiophene-alt-p-phenylene) (PCPDTPP) has been synthesized in a controlled way via catalyst transfer condensative polymerization (CTCP) of the corresponding biaryl monomer. Therefore, a series of Ni catalysts as well as (new) Pd-PEPPSI catalysts were employed in different Kumada CTCPs (KCTCPs) and Negishi CTCPs (NCTCPs). A series of tests confirmed the absence of undesired transfer and termination reactions and, hence, the controlled character of the chain-growth polymerization with Ni(dppe)Cl-2 as catalyst. This resulted in polymers with low dispersities (D = 1.2), (M) over bar (n) of 33 kDa, and relatively good end-group control. Furthermore, formation of PCPDTPP-b-poly(3-octylthiophene) (P3OT) block copolymers was possible. Via optical analysis and DSC measurements, we demonstrated that the conjugated alternating PCPDTPP copolymer is an amorphous, strongly fluorescent polymer with a fluorescence quantum yield (phi(f)) of 58% in chloroform.