Stereochemistry can have a profound impact on polymer and materials properties. Unfortunately, straightforward methods for realizing high levels of stereocontrolled polymerizations are often challenging to achieve. In a departure from traditional metal‐mediated ring‐opening metathesis polymerization (ROMP), we discovered a remarkably simple method for controlling alkene stereochemistry in photoredox mediated metal‐free ROMP. Ion‐pairing, initiator sterics, and solvation effects each had profound impact on the stereochemistry of polynorbornene (PNB). Simple modifications to the reaction conditions produced PNB with
- Award ID(s):
- 2108266
- PAR ID:
- 10539703
- Publisher / Repository:
- RSC
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 59
- Issue:
- 94
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 13993 to 13996
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract trans alkene content of 25 to >98 %. Highcis content was obtained from relatively larger counterions, toluene as solvent, low temperatures (−78 °C), and initiators with low Charton values. Conversely, smaller counterions, dichloromethane as solvent, and enol ethers with higher Charton values enabled production of PNB with hightrans content. Data from a combined experimental and computational investigation are consistent with the stereocontrolling step of the radical cationic mechanism proceeding under thermodynamic control. -
Abstract Stereochemistry can have a profound impact on polymer and materials properties. Unfortunately, straightforward methods for realizing high levels of stereocontrolled polymerizations are often challenging to achieve. In a departure from traditional metal‐mediated ring‐opening metathesis polymerization (ROMP), we discovered a remarkably simple method for controlling alkene stereochemistry in photoredox mediated metal‐free ROMP. Ion‐pairing, initiator sterics, and solvation effects each had profound impact on the stereochemistry of polynorbornene (PNB). Simple modifications to the reaction conditions produced PNB with
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Abstract A toolbox of living coordination polymerization methods based on CPAM group 4 metal initiators has been applied for the stereomodulation of poly(4‐methyl‐1‐pentene) (PMP) tacticity to provide new fundamental forms in which thermal phase transitions,
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