The development of porous materials is of great interest for the capture of CO2from various emission sources, which is essential to mitigate its detrimental environmental impact. In this direction, porous organic polymers (POPs) have emerged as prime candidates owing to their structural tunability, physiochemical stability and high surface areas. In an effort to transfer an intrinsic property of a cyclotetrabenzoin‐derived macrocycle – its high CO2affinity – into porous networks, herein we report the synthesis of three‐dimensional (3D) macrocycle‐based POPs through the polycondensation of an octaketone macrocycle with phenazine‐2,3,7,8‐tetraamine hydrochloride. This polycondensation was performed under ionothermal conditions, using a eutectic salt mixture in the temperature range of 200 to 300 °C. The resulting polymers, named 3D‐mmPOPs, showed reaction temperature‐dependent surface areas and gas uptake properties. 3D‐mmPOP‐250 synthesized at 250 °C exhibited a surface area of 752 m2 g−1and high microporosity originating from the macrocyclic units, thus resulting in an excellent CO2binding enthalpy of 40.6 kJ mol−1and CO2uptake capacity of 3.51 mmol g−1at 273 K, 1.1 bar.
- Award ID(s):
- 1904998
- NSF-PAR ID:
- 10287096
- Date Published:
- Journal Name:
- Organic Materials
- Volume:
- 03
- Issue:
- 02
- ISSN:
- 2625-1825
- Page Range / eLocation ID:
- 346 to 352
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Cooperativity plays a critical role in self‐assembly and molecular recognition. A rigid aromatic oligoamide macrocycle with a cyclodirectional backbone binds with DABCO‐based cationic guests in a 2 : 1 ratio in high affinities (
K total≈1013 M−2) in the highly polar DMF. The host–guest binding also exhibits exceptionally strong positive cooperativity quantified by interaction factors α that are among the largest for synthetic host–guest systems. The unusually strong positive cooperativity, revealed by isothermal titration calorimetry (ITC) and fully corroborated by mass spectrometry, NMR and computational studies, is driven by guest‐induced stacking of the macrocycles and stabilization from the alkyl end chains of the guests, interactions that appear upon binding the second macrocycle. With its tight binding driven by extraordinary positive cooperativity, this host–guest system provides a tunable platform for studying molecular interactions and for constructing stable supramolecular assemblies. -
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1055/a-1512-5753
