Twisting poly(3-substituted thiophene)s: cyclopolymerization of gemini thiophene monomers through catalyst-transfer polycondensation

Abstract

Polythiophenes are an important class of materials in the field of organic electronics. The molecular structures of polythiophenes have a critical role in determining device performance; therefore, substantial efforts have been devoted to controlling their regioregularity, molecular weight and polydispersity. Herein, we demonstrate a new approach for controlling another structural parameter, the dihedral angle. We exploited the unique polymerization mechanism of cyclopolymerization: an alternating intramolecular-intermolecular chain propagation that produces a series of cyclic molecules along the polythiophene chain. We designed gemini thiophene monomers in which two thiophene monomers are tethered by an alkylene strap and we processed the monomers by using the catalyst-transfer polycondensation method. We found that the dihedral angle in the polythiophene is dictated by the size of the macrocycle formed.

Group 16 conjugated polymers based on furan, thiophene, selenophene, and tellurophene

“…3), including the whole series of Group 16 aromatic heterocycles. A large library of substituents has been established to diversify thiophene monomers, including alkyl, 41,42 alkyl ester, 43,44 alkyl ether, 45 oligoethylene glycol, 24,[45][46][47] thioether, 25,48 substituted aryl, 28,[49][50][51][52][53] alkynyl, 54 and a-ketal. 55 However, the diversity of functional groups is limited by their compatibility with relatively active Grignard and Negishi reagents.…”

Cyclopolymerizations: Synthetic Tools for the Precision Synthesis of Macromolecular Architectures

“…Ni-catalyzed catalyst-transfer polycondensation was used for the cyclopolymerization of a bis(2-bromo-5-iodothiophene) monomer (Figure 77). 401 Insoluble polymers form under the monomer concentration of 100 mM. However, soluble polymers can be obtained under more diluted condition (6 mM).…”

Recent developments in the synthesis of regioregular thiophene-based conjugated polymers for electronic and optoelectronic applications using nickel and palladium-based catalytic systems

“…Chunhui Zhao and co-workers in 2017 utilized the cyclopolymerization technique for the synthesis of polythiophenes for the rst time. 210 Cyclopolymerization is useful for the monomers containing two polymerizable moieties and results in the formation of insoluble cross-linked polymer networks. In cyclomerization, alternating intramolecular-intermolecular chain propagation produces a series of cyclic molecules along the polymer chain and, to achieve this, the monomers are generally designed such that thermodynamically favored ve or six-membered rings are formed.…”