Synthesis and Photophysical and Electroluminescent Properties of Poly(1,4-phenylene–ethynylene)-alt-poly(1,4-phenylene–vinylene)s with Various Dissymmetric Substitution of Alkoxy Side Chains

Abstract

The synthesis and characterization of a set of conjugated polymers, poly(1,4-phenylene–ethynylene)-alt-poly(1,4-phenylene–vinylene)s (PPE–PPVs), with a dissymmetrical configuration (partial or total) of alkoxy side chains is reported. Five new polymers bearing octyloxy and/or octadecyloxy side chains at the phenylene–ethynylene and phenylene–vinylene segments, respectively, were obtained. Two symmetrical substituted polymers were used for comparison. Polymers with weight-average molecular weight, Mw, up to 430 000 g/mol and degree of polymerization between 17 and 322 were obtained by a Horner–Wadsworth–Emmons olefination polycondensation reaction of the respective luminophoric dialdehydes and bisphosphonates. As expected, identical conjugated backbones in all polymers results in very similar photophysical response in dilute solution, with high fluorescence quantum yields between 50% and 80%. In contrast, the thin film properties are dependent on the combinatorial effects of side chain configuration, molecular weight, and film thickness parameters, which are the basis of the resulting comparison and discussion.

Explaining the Cyclic Voltammetry of a Poly(1,4‐phenylene‐ethynylene)‐alt‐poly(1,4‐phenylene‐vinylene) Copolymer upon Oxidation by using Spectroscopic Techniques

“…The synthesis of the copolymer P18‐8/8 is described elsewhere . The copolymer was dissolved in chlorobenzene (VWR chemicals) to obtain a concentration of 0.02 mol L −1 .…”

Defining side chain successions in anthracene-based poly(arylene ethynylene)-alt-poly(phenylene vinylene)s: probing structure–property relationships

“…The three 2,5-dialkoxy-p-xylylene bis(diethylphosphonate)s equipped with two octyloxy (3aa), two 2-ethylhexyloxy (3bb) or both side chains (3ab) were prepared from hydroquinone and p-octyloxyphenol, respectively. 31,40 Sequences of Williamson etherification, bromomethylation and the Michaelis-Arbuzov reaction provided the bisphosphonates via the respective intermediates (1aa, 1bb, 1ab and 2aa, 2bb, 2ab; Scheme S1 †).…”

“…The results exhibit many similarities to findings on related structures in preceding studies. 18,31,34,39,41 While the presence of the linear octyloxy and branched 2-ethylhexyloxy side chain is clearly reflected in the 1 H NMR spectra by several specific signal sets, the differentiation between the spectral outputs for the respective double dissymmetric regioisomeric phenylene derivatives, such as 7ba and 7ab (Fig. S1 †), is subtle.…”

“…This enables the realization of versatile PAE-PAV layouts, and allows for the implementation and systematic investigation of diverse side chain configurations. [28][29][30][31][32][33] The anthracene-containing polymer AnE-PVstat exhibits the best solar cell performance for a PPV-type material so far. Due to the balanced effects of linear octyloxy, permitting strong π-π stacking, and branched 2-ethylhexyloxy chains, stimulating an amorphous film morphology, good power conversion efficiencies of up to nearly 5% could be achieved.…”

“…[34][35][36] Although the majority of PAE-PAVs possess identical alkoxy side chains at individual phenylene units, a few with mixed configuration, methoxy/2-ethylhexlyoxy or octyloxy/octadecyloxy, were prepared as well. 18,31,[37][38][39] To further elaborate the insights on side chain-induced structure-properties relationships the present article reports on the synthesis and investigation of anthracene-containing poly(arylene ethynylene)-alt-poly(phenylene vinylene)s (AnE-PVs) bearing various combinations and sequences of isomeric octyloxy and 2-ethylhexyloxy side chains. The crucial step for the structural layout lies in the preparation of double dissymmetric functionalized phenylene building blocks (Schemes 2 and 3).…”