Ni(II)-Complex Anchored Over Functionalized Mesoporous SBA-15: A Nanocatalyst for the Synthesis of Aminophenoxazinone Derivatives

Immobilization of the reactive metal sites over high surface area porous nanomaterial is a very demanding route in designing novel nanocatalysts for the synthesis of valuable fine chemicals. Here we report an efficient, eco-friendly and sustainable route for the synthesis of aminophenoxazinone derivatives via oxidative coupling of o-aminophenols catalysed by a novel mesoporous highly ordered Ni(II)-complex functionalized mesoporous heterogeneous organosilica catalyst. A novel structurally characterized Ni(II)-complex derived from 2-(I-(2-(piperizin-1-yl) ethylimino) methyl)-5-methylphenol ligand has been immobilised over a 2D-hexagonally ordered functionalized mesoporous SBA-15 synthesized via surface functionalization of SBA-15 material with 3-aminopropyltriethoxysilane (APTES) to obtain the Ni(II)-nanocatalyst SANI. Its catalytic activity has been explored for three different substrates like o-aminophenol (OAP), 3-amino-4-hydroxybenzoic acid (CAP) and 2-amino-4-methylphenol (MAP) that produces corresponding phenoxazinone derivatives having the yields of 92, 81 and 85 %, respectively. suggesting wide scope of this supported mesoporous nanocatalyst. One-pot room-temperature oxidative coupling: This work demonstrated a sustainable method for synthesizing aminophenoxazinone derivatives via oxidative coupling of o-aminophenols by employing a catalyst SANI where a novel Ni(II)-complex catalyst has been immobilized on mesoporous functionalized SBA-15. SANI exhibits high catalytic activity, yielding 92 %, 81 %, and 85 % products for o-aminophenol, 3-amino-4-hydroxybenzoic acid, and 2-amino-4-methylphenol substrates, respectively, showcasing its broad applicability. image