Poly(α-vinyl-ω-alkyloligothiophene) Side-Chain Polymers. Synthesis, Fluorescence, and Morphology

Abstract

The synthesis of polyvinyl polymers by radical polymerization of α-vinyl-ω-alkyl-terminated thiophene and bi-, ter-, and quaterthiophenes is reported. The photoluminescence properties of the polymers in solution and in thin film are described. In thin film, self-assembly-induced white photoluminescence was observed for poly(5-vinyl-5‘ ‘‘-hexylquaterthiophene). For this polymer, single crystals with rectangular shape and micrometer size were obtained by drop casting from CS2. MM3 calculations on model diads and triads indicate that, on increasing the size of the side groups, van der Waals interactions promote the stacking of the pendants on the same side of the polyvinyl chain.

Naphthalene-based oligothiophene-stacked polymers

“…Poly(dibenzofulvene)s, 4-11 7,7-diarylnorbornane-containing conjugated polymers, 12,13 cyclophanecontaining polymers and face-to-face ferrocene polymers [36][37][38] have been synthesized, and their optical and electrochemical properties have been studied in detail. Polymers with layered aromatic rings and p-electron systems have also been investigated; [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] for example, Chen et al 53 recently reported the synthesis and formation of a twodimensional assembly of polymeric ladder phanes containing face-toface p-electron systems. These polymers have potential applications in optoelectronic devices and single-molecular devices such as singlemolecular wires.…”

Polyvinyl‐Locked versus Free Quaterthiophene: Effect of Spatial Constraints on the Electronic Properties ofn‐Hexylquaterthiophene

“…In agreement with this, NMR spectra (see Figure SI 2 in the Supporting Information), which perfectly matched those of the longer polymer reported in ref. [17], displays sharper peaks in accordance with a short polymer length and lower polydispersity. In the NMR spectrum, the signals pertaining to chain ends X are hidden by the intense peaks of the hexyl chains.…”

“…[17] The molecular structure of the low-weight fraction of PT4Hex is identified by matrix-assisted laser desorption/ionization (MALDI) analysis and by proton and carbon-13 NMR spectroscopy. MALDI analysis (see Figure SI 1 Supporting Information) shows a peak at about 1315 as the higher mass detected, corresponding to a triad of repeated monomers.…”

“…[11][12][13][14][15][16][17][18] Recently, we described the synthesis by radical polymerization of poly(a-vinyl-w-alkyloligothiophenes) side chain polymers and analyzed their photoluminescence properties and morphology in relation to the pendant size. [17] Theoretical calculations on model diads and triads of the polymers predicted that on increasing the pendant size, the van der Waals interactions promote the stacking of the pendants on the same side of the polyvinyl chain. In particular, for quaterthiophene pendants, the calculations showed that-despite the separation introduced by the aliphatic linker-proximity effects and relative orientation caused the overlap of the p orbitals of the pendants to affect the frontier orbital energies.…”

“…Unfortunately, poly(a-vinyl-w-quaterthiophene) side-chain polymer is a poorly soluble, intractable, material. [17] We have now succeeded in isolating a soluble short fraction of poly(a-vinyl-w-hexylquaterthiophene) consisting of a triad of pendant n-hexylquaterthiophene units (PT4Hex, Figure 1). Herein, by means of optical characterizations, X-ray diffraction (XRD) analysis and cyclic voltammetry experiments, we show that in the polyvinyl-locked structure the quaterthiophene moieties adopt a cofacial arrangement with a mutual distance of about 4 , which is close enough for p-p orbital overlap to occur.…”