Maryam Ranjbar

Synthesis of Lead(II) Minoxidil Coordination Polymer: A New Precursor for Lead(II) Oxide and Lead(II) Hydroxyl Bromide

A new lead(II) coordination polymer, [PbBr2(C9H15N5O)]n (1), where C9H15N5O is (2,4-diamino-6-piperidine-1-yl) pyrimidine N-oxide (minoxidil) is synthesized and characterized. Polymer 1 is synthesized in methanol by sonochemical and hydrothermal methods from lead(II) acetate, KBr and the minoxidil ligand. The crystal structure of [PbBr2(C9H15N5O)]n indicates a syndiotactic coordination polymer. The Pb(II) atom lies on a mirror plane; the mirror plane is perpendicular to the pyrimidine ring bisecting the piperidine ring. N–H···O intramolecular and C–H···Br, N–H···N strong intermolecular interactions were observed. Micro-rods of PbO and nano-plates of PbOHBr were prepared by thermal decomposition of the nano-structured [PbBr2(C9H15N5O)]n as a precursor. Characterization of the products was carried out using X-ray crystallography, elemental analysis, FTIR spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and thermal analysis. The sonochemical method resulted in a significant reduction of reaction time, reaction temperature and particle sizes of the products.

Ultrasound and Microwave-Assisted Co-precipitation Synthesis of La0.75Sr0.25MnO3 Perovskite Nanoparticles from a New Lanthanum(III) Coordination Polymer Precursor

In the present study nano-sized strontium-doped lanthanum manganite, La0.75Sr0.25MnO3 (LSM), were synthesized by three simple different methods (a) co-precipitation, (b) ultrasonic and (c) microwave-assisted co-precipitation. A lanthanum(III) coordination polymer, [pyda.H]2[La2(pydc)4(H2O)4]·2H2O, where [pyda.H]+ = 2,6-diaminopyridinium, and (pydc)2− = 2,6-pyridinedicarboxylate, was used as a new precursor. The products were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), thermal gravimetric (TG) and differential thermal analyses (DTA), as well as by Energy-dispersive X-ray spectroscopy (EDX). The XRD results showed that the crystal lattice of the product obtained was orthorhombic perovskite structure. The porosity, particle size and homogeneity of calcinated LSM were strongly dependent on the preparation method. In addition, the results proved that the product formation time was decreased considerably when ultrasonic or microwave irradiation methods were used.

Preparation and characterization of nanopowder nickel oxide/gadolinium-doped ceria via the sol-gel method by NiLH2 precursor

In the present research two different kinds of nickel oxide/gadolinium-doped ceria (NiO–GDC) (I and II) nanocomposites were prepared by means of the sol-gel method. The Ni(II) complex (NiLH2), [Ni(pydc)2·2(pyda·H)·2H2O], [pydc (2,6-Pyridinedicarboxylic acid), pyda (2,6-diaminopyridine)], and Ni(NO3)2·6H2O have been used as precursors. Characterization of the products was carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray powder diffraction, zeta potential, thermogravimetric analysis, and nitrogen adsorption–desorption Brunauer, Emmett, and Teller measurements. The X-ray powder diffraction results showed that the crystal lattice of compound (I) was obtained as a cubic fluorite structure and was found to have an average crystalline size of 48–63 nm. The comparison of the zeta potential of compounds (I) and (II) has shown that compound (I) can carry a more positive charge and is almost stable. The scanning electron microscope and Brunauer, Emmett, and Teller analysis of compound (I) revealed large homogeneous agglomerated pores and surface area. The results show that if compound (I) is used in solid oxide fuel cells, it could be a suitable material for the anode of solid oxide fuel cells.Graphical Abstract