Catalytic activities of novel silica-supported multifunctional Schiff base ligand & metal complexes under microwave irradiation

• Synthesis of novel silica-supported azo-containing Schiff base ligand and its four metal complexes are investigated.
• Catalytic oxidation of cyclohexane under microwave power is discussed.
• Those of novel catalysts in this paper show remarkable performance.

In this paper, a novel solid phase supported Schiff base ligand (L1: MDPMP) was prepared from 2-hydroxy-5-((2-methoxyphenyl)diazenyl) benzaldehyde (L: HMDB) and silica-gel, activated with 3-aminopropyltriethoxysilane (APTES). Cu (II), Co (II), Ni (II) and Mn (II) complexes of silica-supported ligand (L1: MDPMP) were obtained. The ligand and its four metal complexes were characterized by using NMR (1H and 13C), FT-MIR/FIR, elemental analysis, ICP-OES, TGA and Scanning Electron Microscope (SEM). Their catalytic performances in catalytic oxidation of cyclohexane were investigated for the selective oxidation of cyclohexane under microwave power. Silica-supported L1–Cu (II) complex was observed well selective catalytic properties for the oxidation of cyclohexane to cyclohexanol and cyclohexanone.

The graphical abstract shows the synthesized silica-supported ligand and coordination mode of metal ions to ligand “L1”. Addition, there are four proposed metal-complex moieties illustrated (Cu (II), Mn (II), Co (II), and Ni (II)).Figure optionsDownload as PowerPoint slide