Well‐Defined End‐Functionalized Conjugated Polymers/Oligomers Exhibiting Unique Emission Properties through the End Groups: The Exclusive Synthesis by Combined Olefin Metathesis with Wittig‐type Coupling

π-Conjugated polymers can serve as active layers in flexible and lightweight electronics, and are conventionally synthesized by transition-metal-mediated polycondensation at elevated temperatures. We recently reported a photopolymerization of electron-deficient heteroaryl Grignard monomers that enables the catalyst-free synthesis of n-type π-conjugated polymers. Herein we provide an experimental and computational investigation of the mechanism of this photopolymerization. Spectroscopic studies performed in situ and after quenching reveal that the propagating species is a radical anion with halide end groups. DFT calculations for model oligomers suggest a Mg-templated SRN1-type coupling, in which Grignard monomer coordination to the radical anion chain avoids the formation of free sp2 radicals and enables C–C bond formation with very low barriers. We find that light plays an unusual role in the reaction, photoexciting the radical anion chain to shift electron density to the termini and thus favor productive monomer binding.

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Synthesis of Well-Defined Oligo(2,5-dialkoxy-1,4-phenylene vinylene)s by Combined Olefin Metathesis and Wittig-type Coupling: Effect of Conjugation Repeat Units and End Groups Toward Optical Properties

Macromolecular Chemistry and Physics ◽

10.1002/macp.201400163 ◽

2014 ◽

Vol 215 (20) ◽

pp. 1973-1983 ◽

Cited By ~ 12

Author(s):

Mohamed Mehawed Abdellatif ◽

Sakkawet Yorsaeng ◽

Akiko Inagaki ◽

Kotohiro Nomura

Keyword(s):

Optical Properties ◽

Olefin Metathesis ◽

Coupling Effect ◽

Phenylene Vinylene ◽

Repeat Units ◽

End Groups ◽

Type Coupling

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Light Directs Monomer Coordination in Catalyst-Free Grignard Photopolymerization

10.26434/chemrxiv.14699979 ◽

2021 ◽

Author(s):

Eliot Woods ◽

Alexandra Berl ◽

Leanna Kantt ◽

Michael Wasielewski ◽

Brandon E. Haines ◽

...

Keyword(s):

Conjugated Polymers ◽

Radical Anion ◽

Elevated Temperatures ◽

Spectroscopic Studies ◽

Computational Investigation ◽

Catalyst Free ◽

Active Layers ◽

End Groups ◽

Type Coupling

π-Conjugated polymers can serve as active layers in flexible and lightweight electronics, and are conventionally synthesized by transition-metal-mediated polycondensation at elevated temperatures. We recently reported a photopolymerization of electron-deficient heteroaryl Grignard monomers that enables the catalyst-free synthesis of n-type π-conjugated polymers. Herein we provide an experimental and computational investigation of the mechanism of this photopolymerization. Spectroscopic studies performed in situ and after quenching reveal that the propagating species is a radical anion with halide end groups. DFT calculations for model oligomers suggest a Mg-templated SRN1-type coupling, in which Grignard monomer coordination to the radical anion chain avoids the formation of free sp2 radicals and enables C–C bond formation with very low barriers. We find that light plays an unusual role in the reaction, photoexciting the radical anion chain to shift electron density to the termini and thus favor productive monomer binding.

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Light Directs Monomer Coordination in Catalyst-Free Grignard Photopolymerization

10.33774/chemrxiv-2021-7hqzk-v2 ◽

2021 ◽

Author(s):

Eliot Woods ◽

Alexandra Berl ◽

Leanna Kantt ◽

Christopher Eckdahl ◽

Michael Wasielewski ◽

...

Keyword(s):

Conjugated Polymers ◽

Radical Anion ◽

Elevated Temperatures ◽

Spectroscopic Studies ◽

Computational Investigation ◽

Catalyst Free ◽

Active Layers ◽

End Groups ◽

Type Coupling

π-Conjugated polymers can serve as active layers in flexible and lightweight electronics, and are conventionally synthesized by transition-metal-mediated polycondensation at elevated temperatures. We recently reported a photopolymerization of electron-deficient heteroaryl Grignard monomers that enables the catalyst-free synthesis of n-type π-conjugated polymers. Herein we provide an experimental and computational investigation of the mechanism of this photopolymerization. Spectroscopic studies performed in situ and after quenching reveal that the propagating species is a radical anion with halide end groups. DFT calculations for model oligomers suggest a Mg-templated SRN1-type coupling, in which Grignard monomer coordination to the radical anion chain avoids the formation of free sp2 radicals and enables C–C bond formation with very low barriers. We find that light plays an unusual role in the reaction, photoexciting the radical anion chain to shift electron density to the termini and thus favor productive monomer binding.

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Advancing conjugated polymers into nanometer-scale devices

Pure and Applied Chemistry ◽

10.1351/pac200678101803 ◽

2006 ◽

Vol 78 (10) ◽

pp. 1803-1822 ◽

Cited By ~ 7

Author(s):

Wenping Hu ◽

Hiroshi Nakashima ◽

Erjing Wang ◽

Kazuaki Furukawa ◽

Hongxiang Li ◽

...

Keyword(s):

Conjugated Polymers ◽

Molecular Level ◽

Nanometer Scale ◽

Transport Mechanisms ◽

Phenylene Ethynylene ◽

Polymer Molecules ◽

Polymer Electronics ◽

End Groups

In this article, we review the possibility of combining conjugated polymers with nanometer-scale devices (nanodevices), in order to introduce the properties associated with conjugated polymers into such nanodevices. This approach envisages combining the highly topical disciplines of polymer electronics and nanoelectronics to engender a new subdirection of polymer nanoelectronics, which can serve as a tool to probe the behavior of polymer molecules at the nanometer/molecular level, and contribute to clarifying transport mechanisms in conjugated polymers. In this study, we exemplify this combination, using a family of linear and conjugated polymers, poly(p-phenylene-ethynylene)s (PPEs) with thiolacetate-functionalized end groups.

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