Progress in the Synthesis of Poly(2,7-Fluorene-alt-1,4-Phenylene), PFP, via Suzuki Coupling.

Abstract

Four different palladium catalysts were evaluated in order to optimize the conditions in the Suzuki coupling protocol with 1,4-diphenylboronic acid and 9,9-bis(6′-bromohexyl)-2,7-dibromofluorene. The commercially available catalysts [Pd(PPh3)4], (1); [Pd(PPh3)2Cl2], (2); [PdCl2(dppe)], (3) and [PdCl2(dppf)]·CH2Cl2, (4) were chosen. Palladium catalysts 1-4 have been previously used successfully in polymerization. K2CO3 was used as base in the presence of the adequate solvent mixture. Poly[9,9-bis(6′-bromohexylfluoren-2,7-diyl)-alt-co-(benzen-1,4-diyl)], PFPBr 2 , was obtained and selected as model to study the polymerization degree. Calibration curves of fluorene were used to perform a real estimation of the molecular weights of the polymers, and also typical polydispersity values were measured. Polymer conversion was determined using coupled size exclusion chromatography−evaporative light scattering detector (SEC−ELSD). The (Z)-Pd(II) catalyst, (4), which contains the electron acceptor ligand dppf, showed the fastest conversion rate at low reaction times, followed closely by catalyst (2), (E)-Pd(II), which presents a conventional PPh3 ligand. The typical Pd(0) catalyst, (1), with phospane ligands, was slower than others and this process needed almost 12 h to convert the monomers in real polymer. Taken together, all these results provide new insights into the polymerization mechanism using different Pd(II) and Pd(0) catalysts, which seem to behave differently when different ligands are used.

Catalysts for Suzuki Polycondensation: Ionic and “Quasi‐Ionic” Amphipathic Palladium Complexes with Self‐Phase‐Transfer Features

“…In fact, the conditions could be improved by selecting partly water-miscible organic solvents such as THF, [12] adding phase-transfer agents such as tricaprylammonium chlorides (Aliquat 336), [13] or using water-soluble sulfonated analogues of triphenylphosphine such as sodium 3-(diA C H T U N G T R E N N U N G phen-A C H T U N G T R E N N U N G ylphosphanyl) benzenesulfonate (LSS-3). [14] In these cases, we think a primary reason for the improvement could be that the base or the boronate anion could readily interact with the Pd center and accelerate the transmetalation step.…”

Fluorene-Based Donor-Acceptor Copolymers Containing Functionalized Benzotriazole Units: Tunable Emission and their Electrical Properties

“…All compounds, designed as P1 or P2, were soluble in common organic solvents such as tetrahydrofuran (THF), chloroform and dichloromethane (>1 mg/mL). Their structures were confirmed by 1 H-NMR and IR spectroscopy, while molecular weights of each batch were determined by SEC-LS with polystyrene calibration [40], and collected in Table 1. P1a-c exhibit longer molecular lengths (n > 7 units) and thus showing a good correspondence with polymeric materials.…”

Polymeric films based on blends of 6FDA–6FpDA polyimide plus several copolyfluorenes for CO2 separation

“…The synthesis of the monomers and the cooresponding copolyfluorenes: Copoly- been synthesized via the Suzuki coupling reaction, using the same method described in previous studies [25][26][27][28][29] .…”