SBA-15-supported copper(II)–2-hydrazinopyridine complex as an efficient reusable catalyst for the selective monoarylation of ammonia

A novel Cu(II)-based heterogeneous catalyst, SBA-15@bis(Py-2-NHNH2)-Cu(II), was prepared via sequential functionalization of SBA-15 with APTES, cyanuric acid, and 2-hydrazinopyridine, followed by Cu(OAc)2 complexation. The catalyst was thoroughly characterized by FT-IR, solid-state13C NMR, TGA, BET, XPS, and EDAX, confirming successful ligand grafting, Cu(II) coordination, and structural integrity. Under optimized conditions in DMSO, the catalyst efficiently promoted ammonia monoarylation with a wide range of aryl halides. It exhibited negligible activity loss and minimal copper leaching (< 0.2%) in the first run and maintained its performance over five consecutive cycles. Hot filtration experiments further confirmed its heterogeneous nature and sustained stability. Post-catalytic characterization by FT-IR and EDAX verified that the catalyst retained its structure and active metal centers. Overall, these results demonstrate that SBA-15@bis(Py-2-NHNH2)-Cu(II) is a robust, recyclable, and sustainable catalyst, providing an effective alternative to precious metals for C-N bond formation.