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Title: Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

Authors:
;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Energy Materials Center at Cornell (EMC2)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1370436
DOE Contract Number:
SC0001086
Resource Type:
Journal Article
Resource Relation:
Journal Name: Macromolecules; Journal Volume: 49; Journal Issue: 15; Related Information: Emc2 partners with Cornell University (lead); Lawrence Berkeley National Laboratory
Country of Publication:
United States
Language:
English

Citation Formats

DeBlase, Catherine R., and Dichtel, William R. Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks. United States: N. p., 2016. Web. doi:10.1021/acs.macromol.6b00891.
DeBlase, Catherine R., & Dichtel, William R. Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks. United States. doi:10.1021/acs.macromol.6b00891.
DeBlase, Catherine R., and Dichtel, William R. 2016. "Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks". United States. doi:10.1021/acs.macromol.6b00891.
@article{osti_1370436,
title = {Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks},
author = {DeBlase, Catherine R. and Dichtel, William R.},
abstractNote = {},
doi = {10.1021/acs.macromol.6b00891},
journal = {Macromolecules},
number = 15,
volume = 49,
place = {United States},
year = 2016,
month = 8
}
  • Since their discovery in 2005, covalent organic frameworks (COFs) have attracted interest as potential materials for gas storage, catalysis, energy storage, and other applications because of their ability to periodically and reliably organize designed functionality into high surface area materials. Most of the first examples relied on boron-containing linkages, which suffer from hydrolytic and oxidative instability that limit their utility. In this Perspective, we describe the trend toward more robust linkages by highlighting the design, synthesis, and properties of several recent examples. Finally, the continued development of new COF chemistries, along with improved understanding of their formation and control ofmore » their final form, will provide a means to harness their molecularly precise solidstate structures for useful purposes.« less
  • Since their discovery in 2005, covalent organic frameworks (COFs) have attracted interest as potential materials for gas storage, catalysis, energy storage, and other applications because of their ability to periodically and reliably organize designed functionality into high surface area materials. Most of the first examples relied on boron-containing linkages, which suffer from hydrolytic and oxidative instability that limit their utility. In this Perspective, we describe the trend toward more robust linkages by highlighting the design, synthesis, and properties of several recent examples. Finally, the continued development of new COF chemistries, along with improved understanding of their formation and control ofmore » their final form, will provide a means to harness their molecularly precise solidstate structures for useful purposes.« less
  • A crystalline material with a two-dimensional structure, termed metal–organic framework-901 (MOF-901), was prepared using a strategy that combines the chemistry of MOFs and covalent–organic frameworks (COFs). This strategy involves in situ generation of an amine-functionalized titanium oxo cluster, Ti6O6(OCH3)6(AB)6 (AB = 4-aminobenzoate), which was linked with benzene-1,4-dialdehyde using imine condensation reactions, typical of COFs. The crystal structure of MOF-901 is composed of hexagonal porous layers that are likely stacked in staggered conformation (hxl topology). This MOF represents the first example of combining metal cluster chemistry with dynamic organic covalent bond formation to give a new crystalline, extended framework of titaniummore » metal, which is rarely used in MOFs. The incorporation of Ti(IV) units made MOF-901 useful in the photocatalyzed polymerization of methyl methacrylate (MMA). The resulting polyMMA product was obtained with a high-number-average molar mass (26 850 g mol–1) and low polydispersity index (1.6), which in many respects are better than those achieved by the commercially available photocatalyst (P-25 TiO2). Additionally, the catalyst can be isolated, reused, and recycled with no loss in performance.« less
  • Two-dimensional covalent organic film with macrocyclic network under simple solvothermal conditions was recently synthesized experimentally [Colson, J. W.; et al. Science 2011, 332, 228], which offers immense potentials for optoelectronic applications as in the case of graphene. Here we systematically investigate the electronic and optical properties of such novel covalent organic frameworks (COF-5, TP-COF and NiPc PBBA-COF) as free-standing sheets using density-functional theory. The results shed considerable light on the nature of spatial carrier confinement with band offset. COF-5 exhibits a type-II heterojunction alignment with the significant valence and conduction band offsets, suggesting an effective spatial carrier separation of electronsmore » and holes. In TP-COF, the valence offset is close to zero related to the dispersed distribution of photoexcited holes over the entire structure, while the conduction-band offset is still remarkable, indicating the effective confinement of photoexcited electrons. NiPc PBBACOF presents a type-I heterojunction alignment where the band-edged wave functions are localized in the same region, achieving the effective spatial carrier congregation. The calculated absorption peaks of the optical absorption of TP-COF and NiPc-PBBA COF frameworks are in agreement with experimental measurements, thus providing theoretical insights into experimental observed transmission spectra of these frameworks.« less