Catechol as a Universal Linker for the Synthesis of Hybrid Polyfluorene/Nanoparticle Materials

Abstract

The attachment of conjugated polymers (CPs), characterized by their optical and electronic properties and excellent processability, to inorganic nanoparticles (NPs), known for their specialized electronic and photonic properties, has proven to result in unique and promising (hybrid) materials. Although CPs can be functionalized with many different end groups, the process to find a correct match between the desired NP and appropriate functional group on the CP is often tedious and time-consuming. This study aims to solve this problem by investigating the potential of catechol as a universal linker molecule for the synthesis of hybrid CP/NP materials. First, the synthesis of poly­(9,9-di­((S)-3,7-dimethyloctyl)­fluorene) via Suzuki–Miyaura catalyst transfer oxidative polycondensation using an external catechol Pd-initiator is investigated. A chain-growth polymerization without transfer reactions for molar masses up to 28.3 kg mol–1 is established without degradation of the catechol in basic environments. These polymers are subsequently used to graft a variety of NP materials, including magnetic- (Fe3O4), plasmonic- (Au), and oxide-type (SiO2) NPs, proving its potential as a universal linker molecule. In addition, the influence of the catechol group on the supramolecular organization of free polyfluorene is investigated by comparison with the well-known o-tolyl end-capped polyfluorenes. From these results, it can be concluded that the catechol group significantly disrupts the formation of well-defined supramolecular architectures. Finally, as a preliminary study, the supramolecular organization of the hybrid NPs is compared to the free polymer using solvatochromism experiments. The results indicate an absence of chiral response upon fixation of the polymer onto a surface.

Tuning the emission and lighting the circularly polarized luminescence of polyfluorene by incorporating a non-emissive polycarbene

“…Among the reported semi-conducting polymers, polyfluorene is particularly interesting due to its excellent optical performance, easy synthetic accessibility and high stability. [9][10][11][12][13][14][15][16][17] Polyfluorene block copolymers are generally fabricated by grafting polyfluorene onto the chain end of another polymer or installing an active initiator onto the chain end of polyfluorene and then chain extending with a second monomer. However, these methods require tedious synthetic manipulation and are time consuming.…”

Polyfluorene-block-poly(phenyl isocyanide) Copolymers: One-Pot Synthesis, Helical Assembly, and Circularly Polarized Luminescence

“…Conjugated polymers exhibit excellent electrical and optical properties and have been extensively utilized in various applications, including light-emitting diodes, solar cells, biomedicines, etc. − For the synthesis of conjugated polymers, the Pd(0)-catalyzed Suzuki cross-coupling polymerization reaction has proved to be a useful tool, affording various conjugated polymers in the previous decades. − Hu et al reported that the preferential oxidation of renewable Pd(0) in the Pd(0) catalyst system during catalysis is important for realizing the transition from step-growth to chain-growth polymerization in Suzuki coupling reactions. Moreover, the Pd(0)/ t- Bu 3 P system has been identified as an effective catalyst for preferential oxidative addition. , Thus, this method has enabled the controlled preparation of π-conjugated polymers, e.g., polyfluorene (PF) and polythiophene, − among which PF is particularly attractive for the preparation of functional copolymers owing to its excellent optical performance and conjugation ability. − For example, Saito et al prepared several star-like copolymers bearing PF and polylactide arms and explored their self-assembly behavior. Mecking’s group designed and synthesized an amphiphilic copolymer comprising PF and poly­(ethylene glycol) blocks.…”