Mixed Alkyl‐ and Alkoxy‐Substituted Poly[(phenylene ethynylene)‐alt‐(phenylene vinylene)] Hybrid Polymers: Synthesis and Photophysical Properties

Abstract

Summary: We report the synthesis, characterisation and photophysical properties of mixed alkyl‐ and alkoxy‐substituted poly[(phenylene ethynylene)‐alt‐(phenylene vinylene)] hybrid polymers with the general constitutional unit: (PhCCPhCCPhCHCHPhCHCH)n (7). The polymers were obtained through the Horner‐Wadsworth‐Emmons olefination reaction of alkyl‐substituted luminophoric dialdehydes, 5a–b, and alkoxy‐substituted bisphosphonates. Contrary to their alkoxy‐substituted congeners, 10a–b, which exhibit solution fluorescence quantum yields close to unity, dialdehydes (5a–b) fluoresce poorly at room temperature, but show phosphorescence at 77 K. High molecular weight polymers were obtained showing poor solubility compared to solely alkoxy‐substituted polymers (11) of the same backbone constitutional units. The presence of alkyl side groups in 7 leads to a 15 nm blue shift of their absorption spectra relative to 11. Both types of polymers show however identical emission spectra with only a slight blue shift (3–4 nm) of the emission peak of 7 relative to 11. This clearly proves that the chromophore system responsible for the emission in both types of compounds is located around the lower‐energy, alkoxy‐substituted phenylene‐vinylene portion of the polymers as confirmed by fluorescence kinetics investigations. magnified image

Poly[(arylene ethynylene)-alt-(arylene vinylene)]s Based on Anthanthrone and Its Derivatives: Synthesis and Photophysical, Electrochemical, Electroluminescent, and Photovoltaic Properties

“…The NMR spectra of the bisphosphonate polycondensation comonomers ( M1 – M3 , Figures S1–S9) are in good agreement with literature. − For Ma – Mc , the 1 H signals (Figure and Figures S10–S12) in the range 10.49–10.44 ppm are attributed to the CHO aldehyde protons while the aromatic protons of the anthanthrone/anthanthrene unit and the phenylene group appear in the range 8.94–7.09 ppm. The CH 2 protons directly linked to the oxygen in the alkoxy side chain, in the phenyl group, as well as, in the anthanthrene unit, are visible in the 4.92–3.49 ppm region.…”

Anthracene Based Conjugated Polymers: Correlation between π−π-Stacking Ability, Photophysical Properties, Charge Carrier Mobility, and Photovoltaic Performance

“…The polymers were synthesized by reaction of dialdehydes 6 with bisphosphonate esters 14 ,, based on well established protocols (see Scheme ). ,− The synthetic paths leading to the starting materials ( 6 and 14 ) are depicted in the Supporting Information (Schemes S1 to S3). Soluble materials were obtained with yields between 50% and 90% after extraction of the products with hot diethyl ether.…”

Diyne-Containing PPVs: Solid-State Properties and Comparison of Their Photophysical and Electrochemical Properties with Those of Their Yne-Containing Counterparts

“…The compounds were obtained through the Horner−Wadsworth−Emmons olefination reaction of various dialkoxy-substituted bisphosphonate esters 3 with diyne-containing dialdehyde 2 . Dialdehyde 2 is always obtained as a byproduct in 2−7% yield during the Sonogashira Pd-catalyzed cross-coupling reaction of 1-ethynyl-4-formyl-2,5-dioctyloxybenzene ( 1 ) 17 with aryl halogenide or aryl dihalogenide, as shown in eq 1. ,18b,19b The direct conversion of 1 into 2 is achieved in yields around 80% through the jointly Pd- and Cu-catalyzed oxidative coupling in the presence of iodine and piperidine (Scheme ). Polymers 4a − d were obtained as orange-red materials in yields between 72 and 87% after reaction times between 2 and 3.5 h. They are soluble in common organic solvents such as chloroform, THF, dichloromethane, toluene, and chlorobenzene.…”

“…This is in line with our previous studies on hybrid phenylene−ethynylene- alt -phenylene−vinylene polymers. Such polymers exhibit enhanced electron affinity and higher photoluminescence efficiencies than PPV. − The question to be answered here is, what effect does the replacement of yne units through diyne units have on photophysical (absorption, emission, fluorescence kinetics) and electrochemical properties of these PPV derivatives? Theoretical calculations have been taken into considerations to substantiate the experimental findings.…”