Catalytic and antimicrobial activities of magnetic nanoparticles supported N-heterocyclic palladium(II) complex: A magnetically recyclable catalyst for the treatment of environmental contaminants in aqueous media

Abstract

A novel magnetic palladium(II) complex bearing N-heterocyclic ligand has been successfully fabricated via directly anchoring and immobilizing the structurally defined 5-(methylthio)-1H-tetrazole with a long tail ((3-chloropropyl)trimethoxysilane) onto the silica encapsulated Fe3O4 nanomagnetic particles (Fe3O4@SiO2-Thiotet-Pd(II)) and used as a magnetically recoverable nanospherical catalyst. Fourier transforms infrared spectroscopy (FT-IR), thermogravimetric-differential thermal analysis (TG-DTA), transmission Electron Microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS) and vibrating sample magnetometer (VSM) analytical techniques have been applied to characterize the magnetic nanocatalyst prepared. The antimicrobial activity of Fe3O4@SiO2-Thiotet-Pd(II) was also evaluated by disk diffusion assay. The synthesized magnetically recoverable nanocatalyst exhibited enormously high catalytic activity in the rapid, efficient, and room temperature reduction of nigrosin (NS), 4-nitrophenol (4-NP), potassium hexacyanoferrate(III) (K3[Fe(CN)6]), and hexavalent chromium [Cr(VI)] in aqueous media. Herein, we describe an unprecedented example of thiotetrazole grafted on Fe3O4@SiO2 nanomagnetic, which can be separated by a magnet and recycled eight times with no appreciable decrease of catalytic activity and efficiency. Generally, NaBH4 induced reduction of NS, 4-NP reduction to 4-aminophenol (4-AP), K3[Fe(CN)6] reduction to K4[Fe(CN)6] as well as HCOOH induced reduction of Cr(VI) to Cr(III) catalyzed by Fe3O4@SiO2-Thiotet-Pd(II) were achieved within an extremely short span of time. The results showed that Fe3O4@SiO2-Thiotet-Pd(II) was effective against Escherichia coli as a gram negative bacteria.