Construction of donor-acceptor polymers containing thiophene-phthalazinone moiety via classic Ullmann CN coupling polymerization and their optical-electrical properties

- The copper catalyzed classic Ullmann CN coupling polymerization was investigated through the model reactions.
- Three phthalazinone-based monomers were polymerized with three thiophene-based monomers via Ullmann polymerization.
- The molecular weights of synthesized polymers are in range of 6.4- 34.6 kDa with PDI between 1.54 and 3.18.
- These nine donor-acceptor polymers show strong UV-Vis-NIR absorption manners and emission color from blue to red regions.

The copper catalyzed Ullmann polymerization is rarely used in polymer chemistry filed owing to the covered mechanism and insufficient conversion. Herein, we present the development of an efficient Ullmann CN coupling polymerization route to synthesize conjugated Donor-Acceptor (D-A) polymers containing thiophene-phthalazinone moiety. The model reactions were carried out to investigate varies solvents, bases, catalytic systems and substrate reactivity effects on the Ullmann CN coupling reactions. We demonstrate that the reaction conversion is highly depended on the substrate reactivity. By designing rational structures of thiophene-based di-bromo monomers, the molecular weights of polymers synthesized by classic Ullmann CN coupling polymerization are high, in range of 6.4-34.6 kDa (PDI = 1.54-3.18) with 77-98% yields. Benefiting from the D-A conjugated effect of thiophene-phthalazinone moiety, the optoelectronics properties were studied and these nine polymers show strong UV-Vis-NIR absorption manners and emission color from blue to red regions. Overall, given the discussions and results in this work offer a new perspective for classic Ullmann CN coupling polymerization to synthesize high molecular weight polymers as promising candidates for photoelectric materials.

We present an efficient Ullmann CN coupling polymerization route to synthesize conjugated donor-acceptor polymers containing thiophene-phthalazinone moiety with strong UV-Vis-NIR absorption manners and emission color from blue to red regions.258