Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 21, 2019 | Published + Supplemental Material
Journal Article Open

Living β-selective cyclopolymerization using Ru dithiolate catalysts


Cyclopolymerization (CP) of 1,6-heptadiyne derivatives is a powerful method for synthesizing conjugated polyenes containing five- or six-membered rings via α- or β-addition, respectively. Fifteen years of studies on CP have revealed that user-friendly Ru-based catalysts promoted only α-addition; however, we recently achieved β-selective regiocontrol to produce polyenes containing six-membered-rings, using a dithiolate-chelated Ru-based catalyst. Unfortunately, slow initiation and relatively low catalyst stability inevitably led to uncontrolled polymerization. Nevertheless, this investigation gave us some clues to how successful living polymerization could be achieved. Herein, we report living β-selective CP by rational engineering of the steric factor on monomer or catalyst structures. As a result, the molecular weight of the conjugated polymers from various monomers could be controlled with narrow dispersities, according to the catalyst loading. A mechanistic investigation by in situ kinetic studies using ^1H NMR spectroscopy revealed that with appropriate pyridine additives, imposing a steric demand on either the monomer or the catalyst significantly improved the stability of the propagating carbene as well as the relative rates of initiation over propagation, thereby achieving living polymerization. Furthermore, we successfully prepared diblock and even triblock copolymers with a broad monomer scope.

Additional Information

© 2019 The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. The article was received on 18 Mar 2019, accepted on 22 Jul 2019 and first published on 22 Jul 2019. The financial support from Creative Research Initiative Program and the Nano-Material Technology Development Program through NRF is acknowledged. We thank NCIRF at SNU for in situ kinetic experiments using ¹H NMR. There are no conflicts to declare.

Attached Files

Published - c9sc01326a.pdf

Supplemental Material - c9sc01326a1_si.pdf


Files (5.1 MB)
Name Size Download all
3.7 MB Preview Download
1.4 MB Preview Download

Additional details

August 19, 2023
October 18, 2023