p-benzoquinone diimines and thiophene based alternating copolymers: organometallic catalyzed syntheses and elementary characterization

Abstract

A series of alternating polymers, which were prepared by coupling of N, N'-dichloro-benzoquinonediimine (a) or 2, 5-dimethyl-N, N'-dichloro-benzoquinonediimine (b) with Grignard reagents of thiophene, were successfully prepared using Ni(II) complexes as catalyst with moderate yields (54-88%) and molecular weights (4.3-7.0×10 3 ). The basic properties of the obtained copolymers were characterized by FT-IR, 1 H NMR, UV-vis absorption, cyclic voltammetry, thermal analysis and Gel permeation chromatography (GPC). The maximum UV-vis absorption of these polymers appears in the range of 410-430 nm and 437-494 nm in DMF and CF 3 COOH, respectively. XRD patterns of these polymers suggest the low crystallinty. After doped by iodine, conductivity of obtained polymers was improved five-eight orders of magnitude relative to their corresponding neutral precursors (the conductivity of them was <10 −13 S/cm). The electrochemical activity of iodine-doped polymers was greatly improved as compared to un-doped ones. The reduction of pristine benzoquinone polymers was also studied in order to tune their properties conveniently.

Nickel‐catalysed Kumada polycondensation of di‐functionalized Grignard reagent with aryl fluoride

“…Compared with polymers synthesized by Suzuki and Stille polymerization, the molecular weight of the polymers obtained in this work and synthesized by the same polymerization method in previous reports was not high enough. One reason is the ease of homo‐coupling during polymerization.…”

“…Many sorts of polymers have been synthesized by di‐functionalized thiophene Grignard reagents. However, the molecular weight obtained in the literature is mainly around 10.0 kDa . There are many reasons for researchers to avoid using Kumada coupling in a polymerization reaction.…”

A comparison of experimental and theoretical studies of benzoquinone modified poly(thiophene): effect of polymerization techniques on the structure and properties

“…7 Several authors have reported the polymerization of polyanthraquinones and poly(p-benzoquinone) through organometallic polycondensation reactions. 8,9 Various results have been reported, based on the mode of synthesis of donor-acceptor polymers and the mechanism of polymerization, but the details regarding the control of the structure as well as morphology resulting from the synthetic conditions are still unexplored, and they are not well-explained even by computational studies. Hence, with the aim to investigate the inuence of polymerization conditions on the electronic structure, opto-electronic properties as well as the morphology of donor-acceptor polymers, the present work reports p-conjugated oligomers composed of thiophene (acceptor) and benzoquinone (donor) units synthesized by different chemical polymerization methods: magnetic stirring, ultrasonication and microwave irradiation.…”