A better understanding of the role that halogens play in Kumada catalyst transfer polycondensation leads to better monomer design.

Methods are described for the preparation of fiber-like nanomaterials that mimic the multilayer structure of organic electronic devices on individual polymer chains. By combining Cu(0) reversible-deactivation radical polymerization (RDRP) and ring-opening metathesis polymerization (ROMP), multiblock bottlebrush copolymers are synthesized from ordered sequences of organic semiconductors. Narrowly dispersed fibers are prepared from materials commonly used as the hole transport, electron transport, and host materials in organic electronics, with molecular weights exceeding 2 × 10 Da and dispersities as low as 1.12. Diblock nanofibers are then synthesized from pairs of semiconducting building blocks, giving nanostructures analogous to p- n junctions that exhibit the reversible electrochemistry of their individual parts. Finally, this strategy is used to construct nanofibers with the structure of phosphorescent organic light-emitting diodes (OLEDs) on single macromolecules, such that the photophysical properties of each component of an OLED can be independently observed. These multiblock nanofibers can be formed from arbitrary organic semiconductors without the need for crystallinity, selective solvation, or supramolecular interactions, providing powerful methods for the miniaturization of materials for organic devices.

A series of four acrylic monomers were synthesized based on p-type organic semiconductor motifs found commonly in organic light-emitting diodes (OLEDs), organic thin-film transistors (OTFTs) and organic photovoltaics (OPVs).

Living polymerizations currently play a central role in polymer chemistry. However, one feature of these polymerizations is often overlooked, namely, the isolation of living polymer chains. Herein we report the isolation of living π-conjugated polymer chains, synthesized by catalyst-transfer polycondensation. Successful preservation of the nickel complex at polymer chain ends is evidenced by nuclear magnetic resonance spectroscopy, end group analysis, and chain extension experiments. When characterizing living chains by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we discovered a unique photoionization–photodissociation fragmentation process for polymers containing a nickel phosphine end group. Living chains are isolated for several types of conjugated polymers as well as discrete living oligomers. Additionally, we are able to recycle the catalysts from the isolated polymer chains. Catalyst recycling after π-conjugated polymerization has previously been impossible without chain isolation. This strategy not only exhibits general applicability to different monomers but also has far-reaching potential for other catalytic systems.