A supported pyridylimine-cobalt catalyst for N-formylation of amines using CO2

N-Formylation of amines with CO2 as a cheap and non-toxic C1-feedstock and hydrosilane reducing agent is a practical and environment friendly method to synthesize formamides. This study describes an efficient and chemoselective mono-N-formylation of amines using CO2 and phenylsilane under mild conditions using a porous metal-organic framework (MOF)-supported single-site cobalt catalyst (pyrim-UiO-Co). The pyrim-UiO-Co MOF has a UiO-topology, and its organic linkers bear a pyridylimine ligated Co catalytic moiety. A wide range of aliphatic and aromatic amines are transformed into desired N-formamides in moderate to excellent yields under 1-5 bar CO2. Pyrim-UiO-Co is tolerant to various functional groups and could be recycled and reused at least 10 times. Mechanistic investigation using kinetic, spectroscopic and density functional theory studies suggests that the formylation of benzylamine proceeds sequentially via oxidative addition of PhSiH3 and CO2 insertion, followed by a turn-over limiting reaction with an amine. Our work highlights the importance of MOF-based Earth-abundant metal catalysts for the practical and eco-friendly synthesis of fine chemicals using cheap feedstocks.

Transition metal single atom-optimized g-C3N4 for the highly selective electrosynthesis of H2O2 under neutral electrolytes

Neutral electrosynthesis of H₂O₂via the 2e^- ORR is attractive for numerous applications, but the low activity and high cost of electrocatalysts have become important constraints. Therefore, the development of cheap and efficient electrocatalysts for the 2e^- ORR is necessary. Herein, we report the embedding of transition metal single atoms (TM SAs) in g-C₃N₄ nanosheets (CNNS). The introduction of TM SAs increases the N-CN content and reduces the C-C/CC content in CNNS, which contributes to the increased selectivity of TM SA/CNNS for the 2e^- ORR. TM SA is the main reason for the enhanced activity of the 2e^- ORR. Based on the results obtained by replacing a series of TM SA, the Ni_0.10 SA/CNNS with optimal N-CN content exhibited the best selectivity (∼98%) and highest yield of H₂O₂ (∼503 mmol g_cat^-1 h^-1), which is ∼14.6 times higher than that of CNNS (∼34.4 mmol g_cat^-1 h^-1). Other TM SA/CNNS also exhibited high activity and selectivity. This study demonstrates the ability of TM SA to modulate the selectivity and activity of CNNS, making it a promising candidate for the 2e^- ORR and providing more reference ideas for the preparation of H₂O₂.

Synthesis of mixed-valence Cu phthalocyanine/graphene/g-C3N4 ultrathin heterojunctions as efficient photocatalysts for CO2 reduction

Mixed-valence Cu phthalocyanine/graphene/g-C3N4 ultrathin heterojunctions for efficient photocatalytic CO2 reduction.

Light-assisted coupling of phenols with CO2 to 2-hydroxybenzaldehydes catalyzed by a g-C3N4/NH2-MIL-101(Fe) composite

The present work described a novel photocatalytic approach for the synthesis of 2-hydroxybenzaldehydes from the coupling of phenols and CO2 in the presence of a base using a graphitic carbon nitride/NH2-MIL-101(Fe) composite under mild conditions.

N-Formylation of amines utilizing CO2 by a heterogeneous metal–organic framework supported single-site cobalt catalyst

Single-site cobalt-hydride supported on oxo-nodes of a porous aluminium metal–organic framework is a chemoselective and reusable catalyst for N-formylation of amines using CO2.