Iron oxide nanospheres and nanocubes modified with carboxyphenyl porphyrin and their magnetic, optical properties and photocatalytic activities in room temperature amide synthesis

Superparamagnetic iron oxide nanoparticles of different shapes and sizes combined with 5-(4-carboxyphenyl)-10,15,20-triphenylporphinatozinc(II) (SPION-ZnCTPP) were prepared and investigated as a novel and potent magnetically responsive photocatalyst. Nanospheres and nanocubes of SPIONs in the sizes of 10 and 20 nm were synthesized using thermal decomposition method before coating with ZnCTPP. Morphologies of SPIONs were observed using a transmission electron microscope (TEM). Herein the attachment of ZnCTPP on particles was studied using various techniques including infrared spectroscopy (IR) and UV–visible spectroscopy and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Moreover, the obtained particles showed superparamagnetic character with saturation magnetization in a range of 10 to 76 emu/g, depending on the size and shape of the SPIONs. The SPION-ZnCTPP showed high photocatalytic activity (52% yield) for amide synthesis between potassium ethanethioate and 4-methoxyaniline under irradiation with a 19 W LED lamp, and this heterogeneous catalyst could be well separated from a solution under the induction of an external magnetic field.