Synthesis of Fe3O4@SiO2@OSi(CH2)(3)NHRN(CH2PPh2)(2)PdCl2 type nanocomposite complexes: Highly efficient and magnetically-recoverable catalysts in vitamin K-3 synthesis

The synthesis of aminomethylphosphine-metal complexes have opened a new perspective to the catalytic applications of organic compounds. Magnetic Fe3O4 nano-core was synthesized using the closed quartz tube with Teflon cover and microwaved 200 degrees C for 1 h with power controlled instrument set to max. 600 W. Novel nano-composite supported; Fe3O4@SiO2(CH2)(3)NHArN(CH2PPh2)(2) and Fe3O4@SiO2(CH2)(3)N(CH2PPh2)(2) type bis(diphenylphosphinomethyl)amino ligands and their Pd(II) complexes have been synthesized and characterized with FT-IR, SEM, EDX, TEM, UV-Visible, XRD and TG/DTA techniques. All the complexes were used as heterogeneous catalysts in the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1, 4-naphthoquinone (vitamin K-3, menadione, 2MNQ) in the presence of hydrogen peroxide and acetic acid. Selectivity reached about 55-60% with a conversion of 90-96% using the nano-magnetite supported aminomethylphosphine-Pd(II) complexes. The complexes were very active in three times in the catalytic recycling experiments in five catalytic cycles. (C) 2016 Elsevier Ltd. All rights reserved.