Iridium/graphene nanostructured catalyst for the N-alkylation of amines to synthesize nitrogen-containing derivatives and heterocyclic compounds in a green process

Abstract

The unprecedented iridium/graphene nanostructured catalyst directly promotes the formation of C–N bonds without the need for pre-activation steps, solvents, alkalis and other additives.

Ligand effect of cyclometallated iridium(iii) complexes on N-alkylation of amines in hydrogen borrowing reactions

“…The vacancies of the coordination unsaturated compound are oen coordinated with the lone pair of electrons of the oxygen atoms of dioxane and DMSO, and can also be coordinated with the lone pair of electrons of the alcohol to form an alcohol coordination intermediate. Based on the above information and preliminary mechanistic studies, [35][36][37] a plausible mechanism for C-N bond formation in the (C^N) 2 Ir(m-Cl) 2 Ir(C^N) 2 /AL catalytic systems was proposed (Scheme 6). In the rst step of the catalytic cycle (step a), the bridge chlorine structure ((C^N)2Ir(m-Cl) 2Ir(C^N)2) of the precursor is opened by the attack of the auxiliary ligand (AL) to form a catalyst.…”

Borrowing Hydrogen Mechanism in Amine Alkylation by Single Atom Nickel Catalysts

“…Using a base to activate the alcohol, Kujur et al suggested a mechanism involving pathway 3 in Figure B, which yielded a metal hydride intermediate in a copper N-doped graphene SAC . A similar intermediate was proposed by Chen in a base-free reaction mechanism initiated by hydride transfer to the metal . In summary, these previous studies shed some light onto the key steps of SAC-catalyzed BH reactions, but the overall picture of the mechanism remains largely unexplored.…”

“…52 A similar intermediate was proposed by Chen in a base-free reaction mechanism initiated by hydride transfer to the metal. 53 In summary, these previous studies shed some light onto the key steps of SAC-catalyzed BH reactions, but the overall picture of the mechanism remains largely unexplored.…”

“…Despite the many experimental and computational studies done on SACs operating under electrochemical, photochemical, and thermal conditions, only a few of them are known to perform BH reactions (Figure ), and their mechanism has been seldom studied. − Lu et al used periodic DFT calculations to study the rate-determining step of the amination of benzyl alcohol with aniline by an iron SAC supported on a doped graphene, in which the hydride was transferred to the iron metal center (pathway 1 in Figure B). The calculations were also used to define the optimal doping of the graphene support but no other reaction steps were explored .…”