Copper‐Incorporated Porous Polydivinylbenzene as Efficient and Recyclable Heterogeneous Catalyst in Ullmann Biaryl Ether Coupling

Abstract

The preparation of efficient and stable heterogeneous catalyst is very important for organic transformations. Herein, we report a copper‐incorporated porous, Schiff base‐modified polydivinylbenzene (PDVB‐SB‐Cu) as an excellent heterogeneous catalyst in promoting Ullmann biaryl ether coupling reactions. PDVB‐SB‐Cu was synthesized by incorporating copper species into PDVB‐SB. Combined characterizations by using 13C NMR, IR, XPS, N2 adsorption, and TEM indicated the synthesis of copper–Schiff base species on porous PDVB. Catalytic tests in the Ullmann biaryl ether coupling of iodobenzene and phenol indicated that the PDVB‐SB‐Cu catalyst gave high activity similar to that of the homogeneous Schiff base‐stabilized copper catalyst. This good reactivity was likely due to the polymer‐based porous materials, which provided more effective interactions between substrates and catalytic centers. Importantly, PDVB‐SB‐Cu has extraordinary recyclability. The advantages of high activities and good recyclability made the PDVB‐SB‐Cu catalyst a new class of solid‐support transition metal catalysts for fine chemical preparation.

Functionalized expanded corn starch‐anchored Cu(I): An efficient and recyclable catalyst for oxidation of 5‐hydroxymethylfurfural to 2,5‐diformylfuran

“…Compared with ECS, the spectrum of ECS‐SB contains two weak bands at 1568 and 1589 cm −1 , associated with pyridyl ring stretching vibrations . In addition, the bands at 477 cm −1 assigned to the Cu—N bond stretching vibration confirmed the interaction between nitrogen atoms in the Schiff base and copper cations, suggesting a Cu—N coordination in the as‐synthesized ECS‐SB‐CuBr.…”

“…ECS and ECS‐NH 2 were synthesized using our previously reported procedure . ECS‐SB was prepared via a modified method reported by Xiao and co‐workers . 2‐Pyridinecarboxaldehyde (1.3338 g, 12 mmol) was added to a mixture of 3‐aminopropyl‐functionalized ECS (2.4445 g) in super‐dry ethanol (60 ml) in a 100 ml round‐bottomed flask.…”

The Importance of Catalyst Wettability

“…Similarly, a series of PDVB-based catalysts with various catalytic sites have been rationally prepared. [18][19][20][21] They all exhibit superior catalytic performance in the conversion of various organic compounds, because of the highly efficient adsorption and transfer of hydrophobic/oleophilic organic reactants in the nanoporous structure of the or-Scheme 2. A) Hydrophobic reactant dispersed in the solvent; B) After adding the hydrophobic catalyst, the process of reactant enrichment in the catalyst via 1) adsorption and 2) transfer steps; C) Enriched reactants in the catalyst.…”

Design and Catalytic Application of Functional Porous Organic Polymers: Opportunities and Challenges

“…The interesting aspect of this study was the consideration of the multitreatments including nitration, reduction, aldimine condensation, and coordination, and the obtained Cu‐metalated Schiff base‐modified PDVB to furnish PDVB‐SB‐Cu by Xiao et. al . Notably, the resultant PDVB‐SB‐Cu exhibited comparable catalytic performance with soluble copper salt in Ullmann biaryl ether coupling maintaining its porous structure.…”