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Title: Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth: Role of Diffusion

Abstract

Deterministic bottom-up approaches for synthesizing atomically well-defined graphene nanoribbons (GNRs) largely rely on the surface-catalyzed activation of selected labile bonds in a molecular precursor followed by step-growth polymerization and cyclodehydrogenation. While the majority of successful GNR precursors rely on the homolytic cleavage of thermally labile C–Br bonds, the introduction of weaker C–I bonds provides access to monomers that can be polymerized at significantly lower temperatures, thus helping to increase the flexibility of the GNR synthesis process. Scanning tunneling microscopy imaging of molecular precursors, activated intermediates, and polymers resulting from stepwise thermal annealing of both Br and I substituted precursors for chevron GNRs reveals that the polymerization of both precursors proceeds at similar temperatures on Au(111). Finally, this surprising observation is consistent with diffusion-controlled polymerization of the surface-stabilized radical intermediates that emerge from homolytic cleavage of either the C–Br or the C–I bonds.

Authors:
ORCiD logo [1];  [2];  [1];  [2];  [3]; ORCiD logo [4];  [5]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Physics
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
  3. Aarhus Univ. (Denmark). iNANO. Dept. of Physics and Astronomy
  4. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division. Kavli Energy NanoSciences Inst.
  5. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division. Kavli Energy NanoSciences Inst.
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Office of Naval Research (ONR) (United States); Academy of Sciences Leopoldina (Germany)
OSTI Identifier:
1436639
Grant/Contract Number:  
AC02-05CH11231; SC0010409; LPDS 2014-09
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 34; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Bronner, Christopher, Marangoni, Tomas, Rizzo, Daniel J., Durr, Rebecca A., Jorgensen, Jakob Holm, Fischer, Felix R., and Crommie, Michael F. Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth: Role of Diffusion. United States: N. p., 2017. Web. doi:10.1021/acs.jpcc.7b02896.
Bronner, Christopher, Marangoni, Tomas, Rizzo, Daniel J., Durr, Rebecca A., Jorgensen, Jakob Holm, Fischer, Felix R., & Crommie, Michael F. Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth: Role of Diffusion. United States. doi:10.1021/acs.jpcc.7b02896.
Bronner, Christopher, Marangoni, Tomas, Rizzo, Daniel J., Durr, Rebecca A., Jorgensen, Jakob Holm, Fischer, Felix R., and Crommie, Michael F. Tue . "Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth: Role of Diffusion". United States. doi:10.1021/acs.jpcc.7b02896. https://www.osti.gov/servlets/purl/1436639.
@article{osti_1436639,
title = {Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth: Role of Diffusion},
author = {Bronner, Christopher and Marangoni, Tomas and Rizzo, Daniel J. and Durr, Rebecca A. and Jorgensen, Jakob Holm and Fischer, Felix R. and Crommie, Michael F.},
abstractNote = {Deterministic bottom-up approaches for synthesizing atomically well-defined graphene nanoribbons (GNRs) largely rely on the surface-catalyzed activation of selected labile bonds in a molecular precursor followed by step-growth polymerization and cyclodehydrogenation. While the majority of successful GNR precursors rely on the homolytic cleavage of thermally labile C–Br bonds, the introduction of weaker C–I bonds provides access to monomers that can be polymerized at significantly lower temperatures, thus helping to increase the flexibility of the GNR synthesis process. Scanning tunneling microscopy imaging of molecular precursors, activated intermediates, and polymers resulting from stepwise thermal annealing of both Br and I substituted precursors for chevron GNRs reveals that the polymerization of both precursors proceeds at similar temperatures on Au(111). Finally, this surprising observation is consistent with diffusion-controlled polymerization of the surface-stabilized radical intermediates that emerge from homolytic cleavage of either the C–Br or the C–I bonds.},
doi = {10.1021/acs.jpcc.7b02896},
journal = {Journal of Physical Chemistry. C},
issn = {1932-7447},
number = 34,
volume = 121,
place = {United States},
year = {2017},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

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Cited by: 6 works
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Figures / Tables:

Figure 1 Figure 1: (a) Schematic representation of the reduction in bond dissociation barrier for iodinated molecular precursors compared to brominated precursors. (b) Structure of the iodinated (1) and brominated (2) molecular precursors. (c) poly-1 obtained through surface-catalyzed step growth polymerization. (d) Fully cyclized chevron GNR 4.

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.