Water-Soluble and Blue Luminescent Cationic Polyelectrolytes Based on Poly(p-phenylene)

Abstract

Two new (dialkylamino)ethoxy-substituted poly(p-phenylene)s (PPP) have been prepared, poly[2,5-bis(3-{N,N-diethylamino}-1-oxapropyl)-1,4-phenylene-alt-1,4-phenylene] (P−NEt2) and poly[2,5-bis(3-{N,N-dimethylamino}-1-oxapropyl)-1,4-phenylene-alt-1,4-phenylene] (P−NMe2). These PPPs were synthesized via Pd-catalyzed Suzuki polymerization and are soluble in organic solvents (THF, chloroform) and dilute aqueous acid. Water-soluble quaternary ammonium functionalized PPPs, poly[2,5-bis(3-{N,N,N-triethylammonium}-1-oxapropyl)-1,4-phenylene-alt-1,4-phenylene] dibromide (P−NEt3 +) and poly[2,5-bis(3-{N,N,N-trimethylammonium}-1-oxapropyl)-1,4-phenylene-alt-1,4-phenylene] dibromide (P−NMe3 +), were easily prepared from the neutral polymers. Number-average molecular weights ranging from 5000 to 19 000 g mol-1 were measured by GPC (relative to PS standards), and these values were standardized to PPP's via universal calibration. The neutral polymer is stable to over 300 °C by TGA, while the alkylated polymers begin to dealkylate at 230 °C. The polymer's electronic absorption is dependent on quaternization with the neutral polymer having a λmax at 350 nm, while the triethyl quaternized polymer's λmax shifts to 330 nm. This corresponds to an electronic band gap (E g) shift from 3.0 to 3.3 eV where E g is defined as the onset of the π to π* transition. The polymers luminesce blue light with an intensity that is a function of ionic composition, allowing them to be used as emitting materials in LED's constructed by both layer-by-layer electrostatic deposition and hybrid ink jet printing methods.

Películas fluorescentes azules basadas en derivados de poli-2,7-fluorenofenilideno

“…La mitad de la masa se mantiene hasta alcanzar la temperatura final del ensayo. Para el polímero 3, la primera transición comienza hacia 120º C con una pérdida del 10% en peso, probablemente asociado a la naturaleza higroscópica del polímero y de pérdida de bromuro de metilo (15). La segunda transición parece transcurrir a una velocidad más lenta, como se aprecia en la Figura 1, y que corresponde de nuevo con la ruptura de la cadena principal.…”

Amplified fluorescence sensing of protease activity with conjugated polyelectrolytes

“…Specifically, the turn-on method works with p-NA peptide derivatives; these derivatives are easily prepared and many are commercially available because they provide the basis for colorimetric assays. In addition, the method can be generalized to p-NA peptides that are negatively charged by using a positively charged CPE (32)(33)(34). The turn-on approach is not limited to p-NA peptides, because a variety of species strongly quench CPE fluorescence, e.g., p-nitrophenyl esters, azobenzene dyes, and diimides.…”

Design and Synthesis of Conjugated Polyelectrolytes

“…A more efficient and universal approach toward cationic poly(p-phenylene)s is shown in Scheme 1.15 [17]. The key monomer, 2,5-bis(3-[N,N-diethylamino]-1-oxapropyl)-1,4-dibromobenzene (31), was synthesized via etherification of dibromohydroquinone (29) in the presence of 2-chloroethyldiethylamine hydrochloride [18]. The Suzuki polymerization between 31 and 1,4-bisphenyl-(1,3,2-dioxaborinane) afforded P39.…”