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

Dinuclear iridium complexes with the general formula (C^N) 2 Ir(μ-Cl) 2 Ir(C^N) 2 (C^N = bidentate ligand with carbon and nitrogen donor atoms) were prepared and used in catalytic systems for N -alkylation of amines through the hydrogen borrowing pathway. Triphenylphosphine derivatives were used as auxiliary in catalytic systems to provide excellent conversion of amines to N -alkylation products in yields ranging from 57% to 100%. The catalytic ability of the catalyst depends on the structure of its coordination ligands, including bidentate ligands (C^N) and triphenylphosphine derivatives. These catalytic systems adopt an environmentally friendly and sustainable reaction process through a hydrogen self-transfer strategy, using readily available alcohols as alkylating agents without the need for bases, solvents, and other additives, showing potential in the synthetic and pharmaceutical industries.