In this work, we report the synthesis of a magnetically recoverable catalyst through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L–Cu(II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined and characterized by energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), and thermogravimetric-differential thermal analysis (TG-DTA) procedures. The [Fe3O4@SiO2-L–Cu(II)] was used for the reduction of Cr(VI), 4-nitrophenol (4-NP) and organic dyes such as Congo Red (CR) and methylene blue (MB) in aqueous media. Catalytic performance studies showed that the [Fe3O4@SiO2–L–Cu(II)] has excellent activity toward reduction reactions under mild conditions. Remarkable attributes of this method are high efficiency, removal of a homogeneous catalyst, easy recovery from the reaction mixture, and uncomplicated route. The amount of activity in this catalytic system was almost constant after several stages of recovery and reuse. The results show that the catalyst was easily separated and retained 83% of its efficiency after five cycles without considerable loss of activity and stability.

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The current study aims to explain recent developments in the synthesis of Pb(II)-azido metal-organic coordination polymers. Coordination polymers are defined as hybrid materials encompassing metal-ion-based, organic linkers, vertices, and ligands, serving to link the vertices to 1D, 2D, or 3D periodic configurations. The coordination polymers have many applications and potential properties in many research fields, primarily dependent on particular host–guest interactions. Metal coordination polymers (CPs) and complexes have fascinating structural topologies. Therefore, they have found numerous applications in different areas over the past two decades. Azido-bridged complexes are inorganic coordination ligands with higher fascination that have been the subject of intense research because of their coordination adaptability and magnetic diversity. Several sonochemical methods have been developed to synthesize nanostructures. Researchers have recently been interested in using ultrasound in organic chemistry synthetics, since ultrasonic waves in liquids accelerate chemical reactions in heterogeneous and homogeneous systems. The sonochemical synthesis of lead–azide coordination compounds resulted from very fantastic morphologies, and some of these compounds are used as precursors for preparing nano lead oxide. The ultrasonic sonochemistry approach has been extensively applied in different research fields, such as medical imaging, biological cell disruption, thermoplastic welding, food processing, and waste treatment. CPs serve as appropriate precursors for preparing favorable materials at the nanoscale. Using these polymers as precursors is beneficial for preparing inorganic nanomaterials such as metal oxides.

In the present study, a magnetically recoverable catalyst is synthesized through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L-Cu (II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined and characterized by energy dispersive X-ray spectrometry (EDS), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), and thermogravimetric-differential thermal analysis (TG-DTA) procedures. Using [Fe3O4@SiO2-L-Cu (II)], 4-Nitrophenol (4-NP), Cr(VI), and organic dyes, e.g., Methylene blue (MB) and Congo Red (CR) were reduced in aqueous media. As shown by results of Catalytic performance investigations, [Fe3O4@SiO2-L-Cu (II)] performance was outstanding concerning reduction reactions in mild conditions. Remarkable attributes of this method are high efficiency, removal of a homogeneous catalyst, easy recovery from the reaction mix, and uncomplicated route. The amount of activity in this catalytic system was almost constant after several stages of recovery and reuse. The results show that the catalyst was efficient and easily recoverable in the successive run without a significant loss of catalytic efficiency.

In the present research, a novel mercury (II) metal organic coordination compound, [Hg(Q)I2]n (Q = pyridine-4-carbaldehyde thiosemicarbazide) with nano rods shape was prepared applying an ultrasonic manner. The synthesized compound was determined with infrared spectroscopy (IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In solid state the coordination polymer takes the appearance of a zig-zag 1D polymer. The coordination number of Hg (II) is four by one sulfur atom of organic ligand and three iodine atoms which two of iodine atoms are coordinated to other repeating units, and one of iodine is unattached. The zig-zag 1D chains interact with neighboring chains via poor interactions, making a 3D supramolecular metal organic polymer.