Porous Organic Polymers with Built-in N-Heterocyclic Carbenes: Selective and Efficient Heterogeneous Catalyst for the Reductive N-Formylation of Amines with CO2

Hui Lv; Wenlong Wang; Fuwei Li

doi:10.1002/chem.201803364

Porous Organic Polymers with Built-in N-Heterocyclic Carbenes: Selective and Efficient Heterogeneous Catalyst for the Reductive N-Formylation of Amines with CO₂

Chemistry. 2018 Nov 7;24(62):16588-16594. doi: 10.1002/chem.201803364. Epub 2018 Oct 17.

Authors

Hui Lv¹, Wenlong Wang², Fuwei Li¹

Affiliations

¹ State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No.18, Tianshui Middle Road, Lanzhou, P.R. China.
² School of Environment and Civil Engineering, Dongguan University of Technology, No.1, Daxue Rd. Songshan Lake, Dongguan, Guangdong Province, P.R. China.

PMID: 30136747
DOI: 10.1002/chem.201803364

Abstract

A series of porous organic polymers (POPs) based on N-heterocyclic carbene (NHC) building blocks has been prepared through an octacarbonyldicobalt complex [Co₂ (CO)₈ ]-catalyzed trimerization of terminal alkyne groups. By changing the monomer ratio in the copolymerization, cross-linked POPs with tunable surface areas of 485-731 m² g^-1 and pore volumes of 0.31-0.51 cm³ g^-1 were easily prepared. Compared with the analogues homogeneous NHC (SIPr) catalysts, the POPs exhibited an enhanced catalytic activity and high selectivity in the reductive functionalization of CO₂ with amines. The extraordinary performance of the sample could be attributed to the combination of the gas enrichment (or storage) effect, enhanced in-pore concentrations of other substrates, and advantageous micropore structures of the porous polymers. Meanwhile, these catalysts can easily be separated and recycled from the reaction systems with only a slight loss of activity. This excellent catalytic performance and facile recycling of heterogeneous catalysts make them very attractive. These NHC-containing POPs may provide a new platform for catalytic transformations of CO₂ .

Keywords: N-heterocyclic carbenes; carbon dioxide; formylation; heterogeneous catalysis; porous organic polymers.