A sustainable strategy for the visible-light-driven facile N-formylation of amines using a Co(ii)-embedded covalent organic framework as an efficient photocatalyst†
Abstract
Nowadays, to tackle the increased greenhouse effect, the development of efficient porous adsorbents with the capacity for rapid atmospheric CO2 uptake is one of the new concerns in environmental remediation. The photocatalytic N-formylation of amines through CO2 reduction offers a green and sustainable approach for the utilization of greenhouse gas CO2. In this regard, we have constructed a highly crystalline 2D imine-linked Co(II)-incorporated Tp-TH COF catalyst (namely, Co(II)@Tp-TH) with a band gap energy of 2.4 eV to serve as a stable and effective porous photocatalyst. Different characterization techniques have been employed to determine the structural and morphological features of the photocatalyst. Moreover, as a novel photocatalyst, Co(II)@Tp-TH exhibits excellent catalytic activity, selectivity and recyclability for the sustainable one-pot synthesis of N-formylated products from a variety of amines, with a maximum TON value of 114 under ambient CO2 pressure in DMF/CH3OH without the need for any reducing agents or co-catalyst. These findings illustrate the development of a new, environmentally preferable green approach for the photocatalytic synthesis of N-formamides, which are essential chemical feedstocks for the production of heterocyclic compounds, medicines, and biologically active compounds.