Conformational Transitions in Chiral, Gallic Acid-Functionalized Poly(dithienopyrrole): A Comparative UV−vis and CD Study

Abstract

An achiral and chiral poly(dithieno[3,2-b:2',3'-d]pyrrole) (PDTP), substituted with a gallic acid derived moiety, was prepared by a Stille-coupling and the supramolecular behavior in solution was studied. In a good solvent (THF), the polymers are present as unordered, highly conjugated, rigid rod-like strands. Upon addition of a nonsolvent (hexane) or in toluene, the polymer strands adopt a helical conformation in contrast to previously reported alkyl-substituted PDTPs, which aggregate by decreasing the solvent quality. The folding and unfolding process was investigated by probing the UV-Vis and CD intensities at different wavelengths and temperatures. Based on these experiments, it could be concluded that the helical folding and unfolding is a single-step process. The PDTP could also be oxidized and re-reduced and thus, in principle, a molecular solenoid can be obtained.

The Influence of Solubilizing Chain Stereochemistry on Small Molecule Photovoltaics

“…), solubilizing groups emerge as important structural components for study and material/device optimization. Indeed, for both oligomers and polymers, side chain type, length, branching, placement, and stereochemistry have independently been shown to influence thin film morphology, charge carrier mobility, and device performance …”

Recent advances in arylene ethynylene folding systems: Toward functioning

“…Ever since the folding behaviors of m-phenylene ethynylene (mPE) oligomers were first reported by Moore and coworkers in 1997 [26], mPE and related arylene ethynylene foldamer systems have been extensively developed and investigated [27][28][29][30][31][32][33][34][35][36][37][38][39]. Compared with many other foldamer systems containing non-natural, aromatic units, such as aromatic oligoamides [15,16,[40][41][42][43], arylene polymer/oligomers [21,24,25,[44][45][46][47][48][49][50][51][52][53][54][55], poly(phenylacetylene)s [21,23,[56][57][58], iso-polydiacetylenes [59,60], poly(N-propargylamides) [61], poly(N-octylcarbazole ethylene) [62], polydiacetylene [63], etc., arylene ethynylene foldable systems (AEFS) exhibit a distinct feature that they mainly rely on weak, noncovalent interactions among non-adjacent backbone units to realize folding...…”

New methods for the synthesis of 4H‐dithieno[3,2‐b:2′,3′‐d]pyrrole

“…Unfortunately, the scope of this approach is rather limited to the above mentioned alkyl and aryl substituents, and only moderate yields can be achieved for functionalized DTPs bearing acyl, amino, or ether residues, respectively. However, it would be highly interesting to have efficient access to functionalized DTPs to either tune electronic or redox properties of DTP‐based oligomers or to prepare corresponding functionalized conducting poly(DTP)s . The attachment of more complex moieties to the DTP core appears very promising by substituting parent 4 H ‐dithieno[3,2‐ b :2′,3′‐ d ]pyrrole 1 at the nitrogen.…”