Highly Efficient and Selective N‐Formylation of Amines with CO₂ and H₂ Catalyzed by Porous Organometallic Polymers

Abstract

The valorization of carbon dioxide (CO2) to fine chemicals is one of the most promising approaches for CO2 capture and utilization. Herein we demonstrated a series of porous organometallic polymers could be employed as highly efficient and recyclable catalysts for this purpose. Synergetic effects of specific surface area, iridium content, and CO2 adsorption capability are crucial to achieve excellent selectivity and yields towards N‐formylation of diverse amines with CO2 and H2 under mild reaction conditions even at 20 ppm catalyst loading. Density functional theory calculations revealed not only a redox‐neutral catalytic pathway but also a new plausible mechanism with the incorporation of the key intermediate formic acid via a proton‐relay process. Remarkably, a record turnover number (TON=1.58×106) was achieved in the synthesis of N,N‐dimethylformamide (DMF), and the solid catalysts can be reused up to 12 runs, highlighting their practical potential in industry.

Catalyst free N-formylation of aromatic and aliphatic amines exploiting reductive formylation of CO2 using NaBH4

“…There is considerable interest in the synthesis of N-formyls directly from feedstock chemicals with high atom and economic efficiency. Methods have been developed where methanol, [15][16][17] CO 18 and CO 2 [19][20][21][22][23][24][25][26][27][28] have been exploited as a formyl surrogate employing various catalysts including transition metals. Carbon dioxide (CO 2 ) is a notorious greenhouse gas but an inexpensive, non-toxic, and abundant source of carbon in synthetic organic chemistry.…”

“…[29][30][31][32] Recently, CO 2 has been used as a formyl surrogate for the synthesis of N-formyls in the presence of a reductant. [19][20][21][22][23][24][25][26][27][28] However, most of these reported methodologies require expensive or complex metal based catalysts [20][21][22]24,[26][27][28] as well as ligands along with hydrogen gas or hydrosilanes 19,25 as a source of hydride under high temperature and pressure. Although these reported methods use substoichiometric amounts of catalysts, still these transformations are far from ideal due to limited product scope as well as poor energy and economic efficiency.…”

Synthesis of Mesoporous PdxCu1–x/Al2O3-y Bimetallic Catalysts Via Mechanochemistry for Selective N-Formylation of Amines with CO2 and H2

“…40 In 2020, Ding and coworkers 41 reported that a Ru-PPh 3 -SO 3 Na@POPs base catalyst exhibited good performance and stability for the synthesis of formamides. Soon after, Tu et al 42 reported that a porous metal−organic polymer (POMP-NHC-Ir) synthesized N,N-dimethylformamide by dimethylamine with CO 2 and H 2 .…”

“…Although CO 2 is safe to utilize, the inherent kinetic inertness and thermodynamic stability limit its application in large-scale formamide synthesis. Currently, many tactics have been developed to obtain formamides by activating CO 2 molecules with hydrosilane, , borohydride, − or hydrogen − as reducing agents. Notably, H 2 is a more desirable reducing agent due to its higher atomic economy and non-polluting properties than hydrosilane or borohydride.…”

“…In 2020, Ding and coworkers reported that a Ru-PPh 3 -SO 3 Na@POPs base catalyst exhibited good performance and stability for the synthesis of formamides. Soon after, Tu et al reported that a porous metal–organic polymer (POMP-NHC-Ir) synthesized N , N -dimethylformamide by dimethylamine with CO 2 and H 2 . Obviously, most of the reported heterogeneous catalysts for the N -formylation of amines with CO 2 and H 2 are single component metals.…”