POS1-1372
TBAB-Assisted Organic-Flux Crystallization of Pyromellitic Acid-Based Polyimide Covalent Organic Frameworks(PI-COFs)
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Myeongjae Lee (Korea Institute of Science and Technology(KIST))
Co-Author(s)
Abstract
Polyimide covalent organic frameworks (PI-COFs) are promising crystalline porous polymers because of their robust imide linkages and structurally tunable frameworks. However, the limited reversibility of imide formation can hinder structural error correction during framework construction, making the synthesis of highly crystalline PI-COFs challenging. Here, we present a tetrabutylammonium bromide (TBAB)-assisted organic-flux strategy for enhancing the crystallization of PI-COFs synthesized from pyromellitic acid (PMA) and aromatic triamine monomers. The reaction conditions were first optimized using 1,3,5-tris(4-aminophenyl)benzene (TAPB) and PMA in the presence of benzoic acid (BA) or salicylic acid (SA) as organic fluxes, together with a controlled amount of water. Under the optimized conditions, the addition of TBAB produced TAPB–PMA COFs with sharper and more intense powder X-ray diffraction peaks than the corresponding TBAB-free samples, indicating improved long-range structural order. To investigate the generality of this approach, the optimized protocol is being extended to additional aromatic triamine monomers, including 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and tris(4-aminophenyl)amine (TAPA), as well as a structurally diverse series of benzoic-acid-based organic fluxes: 2-fluorobenzoic acid, 2-chlorobenzoic acid, 2-methylbenzoic acid, 2-methoxybenzoic acid, 2-(trifluoromethyl)benzoic acid, and pentafluorobenzoic acid. These systematic studies are designed to clarify how the electronic and steric properties of the organic flux influence PI-COF nucleation and crystal growth. This work suggests that combining controlled water content, an organic flux, and TBAB may provide a versatile synthetic platform for obtaining highly ordered PI-COFs.
