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Title: In situ formation of pyridyl-functionalized poly(3-hexylthiophene)s via quenching of the Grignard metathesis polymerization: Toward ligands for semiconductor quantum dots

Abstract

The synthesis of well-defined, end-functional poly(3-hexylthiophene)s (P3HTs) by in situ quenching of the Grignard metathesis (GRIM) polymerization is complicated by the extreme tendency to favor difunctional products in all but a few cases. A facile one-pot method for preparing 2-pyridyl and 3-pyridyl P3HTs with high abundance of monofunctional products is established via an examination of the kinetics of the end-functionalization quenching reaction with lithium chloride complexes of 2- and 3-pyridyl Grignard reagents. Density functional theory calculations guide the selection of pyridine as the end group, which provides the capacity to ligate cadmium selenide (CdSe) nanocrystals and arrests aggregation upon thermal annealing when dispersed in a P3HT matrix. The relative abundances of various end-functional products, as ascertained by high-resolution matrix assisted laser desorption ionization time-of-flight mass spectrometry, can be altered through the use of 1-pentene as an additive: GRIM polymerizations quenched with 3-pyridyl and 2-pyridyl Grignard reagents show 5% and 18% abundances of difunctional, pyridyl-capped P3HTs, respectively, when 1-pentene is present at 1000:1 relative to the nickel catalyst. This represents a significant improvement compared to quenching with aryl Grignard reagents, where difunctional products predominate. Furthermore, the ability to manipulate end group compositions coupled with the propensity of pyridyl-functionalized P3HTs to ligatemore » semiconductor quantum dots (SQDs) opens new possibilities for tuning the morphology of conjugated polymer/SQD blends.« less

Authors:
 [1];  [2];  [2];  [2];
  1. Univ. of Tennessee, Knoxville, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1055176
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 24; Journal Issue: 22; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DFT; Grignard metathesis polymerization; poly(3-hexylthiophene); self-assembly

Citation Formats

Kochemba, William Michael, Pickel, Deanna L., Sumpter, Bobby G., Chen, Jihua, and S. Michael Kilbey, II. In situ formation of pyridyl-functionalized poly(3-hexylthiophene)s via quenching of the Grignard metathesis polymerization: Toward ligands for semiconductor quantum dots. United States: N. p., 2012. Web. doi:10.1021/cm302915h.
Kochemba, William Michael, Pickel, Deanna L., Sumpter, Bobby G., Chen, Jihua, & S. Michael Kilbey, II. In situ formation of pyridyl-functionalized poly(3-hexylthiophene)s via quenching of the Grignard metathesis polymerization: Toward ligands for semiconductor quantum dots. United States. doi:10.1021/cm302915h.
Kochemba, William Michael, Pickel, Deanna L., Sumpter, Bobby G., Chen, Jihua, and S. Michael Kilbey, II. Thu . "In situ formation of pyridyl-functionalized poly(3-hexylthiophene)s via quenching of the Grignard metathesis polymerization: Toward ligands for semiconductor quantum dots". United States. doi:10.1021/cm302915h.
@article{osti_1055176,
title = {In situ formation of pyridyl-functionalized poly(3-hexylthiophene)s via quenching of the Grignard metathesis polymerization: Toward ligands for semiconductor quantum dots},
author = {Kochemba, William Michael and Pickel, Deanna L. and Sumpter, Bobby G. and Chen, Jihua and S. Michael Kilbey, II},
abstractNote = {The synthesis of well-defined, end-functional poly(3-hexylthiophene)s (P3HTs) by in situ quenching of the Grignard metathesis (GRIM) polymerization is complicated by the extreme tendency to favor difunctional products in all but a few cases. A facile one-pot method for preparing 2-pyridyl and 3-pyridyl P3HTs with high abundance of monofunctional products is established via an examination of the kinetics of the end-functionalization quenching reaction with lithium chloride complexes of 2- and 3-pyridyl Grignard reagents. Density functional theory calculations guide the selection of pyridine as the end group, which provides the capacity to ligate cadmium selenide (CdSe) nanocrystals and arrests aggregation upon thermal annealing when dispersed in a P3HT matrix. The relative abundances of various end-functional products, as ascertained by high-resolution matrix assisted laser desorption ionization time-of-flight mass spectrometry, can be altered through the use of 1-pentene as an additive: GRIM polymerizations quenched with 3-pyridyl and 2-pyridyl Grignard reagents show 5% and 18% abundances of difunctional, pyridyl-capped P3HTs, respectively, when 1-pentene is present at 1000:1 relative to the nickel catalyst. This represents a significant improvement compared to quenching with aryl Grignard reagents, where difunctional products predominate. Furthermore, the ability to manipulate end group compositions coupled with the propensity of pyridyl-functionalized P3HTs to ligate semiconductor quantum dots (SQDs) opens new possibilities for tuning the morphology of conjugated polymer/SQD blends.},
doi = {10.1021/cm302915h},
journal = {Chemistry of Materials},
issn = {0897-4756},
number = 22,
volume = 24,
place = {United States},
year = {2012},
month = {11}
}