Porous Aromatic Framework Nanosheets Anchored with Lewis Pairs for Efficient and Recyclable Heterogeneous Catalysis

Abstract

Lewis pairs (LPs) with outstanding performance for nonmetal-mediated catalysis reactions have high fundamental interest and remarkable application prospects. However, their solubility characteristics lead to instability and deactivation upon recycling. Here, the layered porous aromatic framework (PAF-6), featuring two kinds of Lewis base sites (N Piperazine and N Triazine), is exfoliated into few-layer nanosheets to form the LP entity with the Lewis acid. After comparison with various porous networks and verification by density functional theory (DFT) calculations, the N Triazine atom in the specific spatial environment is determined to preferably coordinate with the electron-deficient boron compound in a sterically hindered pattern. LP-bare porous product displays high catalytic activity for the hydrogenation of both olefin and imine compounds, and demonstrates ≈100% activity after 10 successful cycles in hydrogenation reactions. Considering the natural advantage of porous organic frameworks to construct LP groups opens up novel prospects for preparing other nonmetallic heterogeneous catalysts for efficient and recyclable catalysis.

Covalent organic frameworks anchored with frustrated Lewis pairs for hydrogenation of alkynes with H2

“…As presented in Fig. S14,† according to the XPS results of the N 1s spectrum, besides the signal peaks of N Imine (399 eV) and N Triazine (398.4 eV) belonging to the original COFs, 48,49 both COFs-1-PPh 2 and COFs-2-PPh 2 showed a new peak at 399.7 eV, corresponding to the N atom of α-aminophosphine.…”

A Facile and Highly Efficient Approach to Obtain a Fluorescent Chromogenic Porous Organic Polymer for Lymphatic Targeting Imaging

“…Thanks to state-of-the-art coupling approaches, great efforts have been made in, for example, crystalline networks of COFs (covalent organic frameworks) and CTFs (covalent triazine-based frameworks) and amorphous networks of PIMs (polymer of intrinsic microporosity), CMPs (conjugated microporous polymers), and PAFs (porous aromatic frameworks) [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. In addition to their porous nature, the tunable structural composition of POP samples is a rare quality, which has been widely used to realize custom-made skeletons for the satisfaction of unique requirements in the areas of molecular capture, gas storage, and catalysis [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Although POPs have helped to make great progress in structural design and molecular interaction, their applications in biology are still in their infancy.…”

Significant Aggregation-Enhanced Carrier Separation in Nanoscopic Catalysts Heterojunction Stacks

“…In artificial materials, catalytically active heterojunctions are receiving intense attention. These heterojunction nanocatalysts are often used as functional aggregates or coating layers for ease of handling or recovery. − Most previous research efforts have been placed in studying the individual heterojunction structure . Despite the omnipresence of the heterojunction stack structures, the mechanism understanding at the aggregate level remains inadequate.…”