Poly(p‐phenylene vinylene) Derivatives with Different Contents of cis‐Olefins and their Effect on the Optical Properties

Abstract

Soluble poly[(2,5‐dihexyloxy‐1,4‐phenylene vinylene)‐alt‐(2,5‐diphenyl‐1,4‐phenylene vinylene)] (DPO‐PPV) with a majority of cis‐vinylenes (>87%) has been synthesized by the Wittig reaction. A series of DPO‐PPV derivatives with different contents of cis‐olefins from approximately 0.05% to 87% was successfully prepared using the photoisomerization technique. On the basis of 1H NMR, Fourier transform IR (FTIR), ultraviolet (UV), and photoluminescence (PL) spectroscopy, as well as fluorescence quantum efficiency measurements, the effect of cis‐olefins on the optical properties of the polymer in solution and in film was systemically studied. The results indicate that with a cis‐configuration above 75%, the luminescence of DPO‐PPV is decayed due to cis‐trans isomerization with rotational motions of the double bonds; however, the luminescence is dramatically improved on increasing of the trans‐configuration.magnified image

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

“…Dialdehyde 7ab was also synthesized in several steps in analogy to the literature for the symmetric substituted compounds. 38 The diiodination of 1-octadecyloxy-4-octyloxybenzene 1ab was followed by a Pd-catalyzed Sonogashira cross-coupling reaction with trimethylsilylacetylene, the deprotection of the acetylene units, and finally another Sonogashira reaction leading to the desired product 7ab , which was obtained as bright yellow substance alongside a small amount of diyne dialdehyde 8ab . For the purification of the materials, column chromatography and/or recrystallization were performed.…”

Poly(phenylenevinylenes)

“…The energetically favorable pathway leads to the effective hole injection and transport in the respective device. [82,83] The yne-containing CN-PPV 41c is similarly synthesized [86], which exhibits higher film fluorescence but lower EL efficiency than the corresponding CN-free polymer. …”

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

“…While this turns out to be valid for the polymers Aa, Ab and Ac, the 1 H NMR spectra of the other polymers (Ba, Bb, Bc, Ca, Cb and Cc) display some weak signals at about 6.8 and 3.6 ppm, indicating a small percentage of cis(Z)-vinylene linkages. 45,46 This suggests that the side chain configuration of the dialdehydes might affect the vinylene linkage formation during HWE reactions in a detectable manner. Here, the presence of an octyloxy chain instead of a 2-ethylhexyloxy chain right next to the formyl group slightly increases the probability of cis-vinylene linkage formation.…”