Please cite this article in press as: Jia et al., Extremely Hydrophobic POPs to Access Highly Porous Storage Media and Capturing Agent for
The exploration of highly porous materials, and their associated potential applica-
tions, has been an active area of research in academia and industry alike. During
the last two decades, metal-organic frameworks (MOFs) with ultra-high surface
area such as MOF-210,6 NU-110,7 and Al-soc-MOF-18 have been vigorously
explored. However, because of the trade-off between high porosity and stability,
most of the highly porous MOFs showed a lessened chemical stability as the surface
area increased and most of them required impractical activation methods such as
supercritical CO2.9 These MOFs usually cannot preserve their structures under
highly acidic or basic conditions, thus limiting their wide industrial applications.
Only recently, Eddaoudi et al. unveiled a unique isostructural soc-MOF based on
Cr satisfying the challenging high porosity-stability trade-off.10
More recently, porous organic polymers (POPs),11–14 offering superior stability to
MOFs because of their robust covalent bonds, have attracted considerable attention
for gas storage15 as well as for separation.16 Irreversible and fast reaction ap-
proaches are usually applied to synthesize POPs. These methodologies lead often
to amorphous polymers with highly heterogeneous structures. As POP structural
features remain usually unknown, it is very challenging to design and construct
POPs with high surface areas.17–20 Only very few examples of POPs have been re-
ported with ultra-high surface areas comparable with MOFs. For example, partially
crystalline PAF-121 possesses an estimated BET (BET = Brunauer-Emmett-Teller) sur-
face area22 of ca. 5,600 m2 ꢀ1. Another reported POP (PPN-4)23 exhibits an even
g
higher BET specific surface area of around 6,400 m2 gꢀ1. The two aforementioned
POPs were both synthesized using 4-connected (4-c) building blocks in order to
mimic the hypothetical diamond (dia) structure. Nevertheless, the use of building
blocks with higher connectivity, i.e., a higher degree of predictability, is of significant
importance and rarely explored.
The molecular building block (MBB) approach24,25 decidedly permits access to POPs
by the assembly of judiciously preselected organic building blocks that code
geometrical information of targeted underlying nets. Although POPs assembled
from 3-connected (3-c) and 4-c MBBs20,26 have been widely explored, 6-c
MBBs27,28 have rarely been studied in constructing 3D POPs, owing to their complex
conformation and the difficulty to predict obtained structures compared with 3-c and
4-c MBBs. Herein, three 6-c MBBs (Figures 1 and S26–S40), i.e., 1,4-bis(tris(4-bromo-
phenyl)silyl)-benzene (MBB-1), 4,40-bis(tris(4-bromophenyl)silyl)-1,10-biphenyl (MBB-2),
and
50-(3,5-diethynylphenyl)-3,300,5,500-tetraethynyl-20,40,60-trimethyl-1,10:30,100-ter-
phenyl (MBB-3), were designed and synthesized as precursors to deliberately
assemble the targeted 3D POPs. Using these MBBs, three POPs, namely KPOP-1,
KPOP-2, and KPOP-3 (KPOP = KAUST [King Abdullah University of Science and
Technology] POP), were synthesized and show high specific BET surface areas of
5,120, 5,730, and 2,620 m2 gꢀ1, respectively. Thanks to their ultra-high porosity, the
reported POPs displayed records of gravimetric uptakes for CH4, CO2, and O2.
Interestingly, KPOP-1 and -2 also show an extremely hydrophobic behavior and an
exceptional adsorption of large amounts of organic vapors, positioning them as very
promising adsorbent materials for the capture of volatile organic compounds (VOCs).
1Functional Materials Design, Discovery and
Development Research Group, Advanced
Membranes and Porous Materials Center,
Division of Physical Sciences and Engineering,
King Abdullah University of Science and
Technology, Thuwal 23955-6900, Saudi Arabia
2King Abdullah University of Science and
Technology, Core Labs, Thuwal 23955-6900,
Saudi Arabia
RESULTS AND DISCUSSION
The Reticular Chemistry Structure Resource (RCSR) lists the nets with underlying
topologies acs, bcs, crs, lcy, and pcu (Figure S1) as the five edge-transitive nets
constructed by one type of 6-c building units with trigonal prism, octahedral, or
trigonal anti-prism geometry.29,30 On the basis of the MBB conformation analysis,
3Lead Contact
*Correspondence:
2
Chem 5, 1–12, January 10, 2019