Cu–Kanamycin complex anchored on graphene oxide (Cu-kana@GO) for aqueous C–N and C–C coupling: A multifunctional recyclable nano catalyst

We report the design of a copper–kanamycin–graphene oxide hybrid catalyst (Cu–Kana@GO) that integrates an aminoglycoside-derived ligand with a redox-active graphene oxide matrix to enable efficient aqueous cross-coupling. The hybrid exhibits superior activity in Ullmann C–N coupling, affording up to 90 % yield within 20 min at 60 °C using K₂CO₃ in water, outperforming conventional Cu@GO systems in both rate and sustainability. Spectroscopic and electrochemical analyses (ESR, cyclic voltammetry, UV–Vis kinetics) reveal a Cu(I)/Cu(II) redox cycle involving radical intermediates and substrate inhibition phenomena, while DFT calculations support a synergistic Cu–GO charge-transfer mechanism. The catalyst retains high performance over six recycling cycles with negligible loss of activity. Notably, Cu–Kana@GO also mediates Chan–Lam and Glaser couplings under identical aqueous conditions, underscoring its broad applicability. These results establish Cu–Kana@GO as a versatile, recyclable platform for sustainable carbon–heteroatom and carbon–carbon bond formation in water.