Preparation Of Nanometer-scale Oxides By Thermo-decomposition And Synthesis Of Lanthanide Complex Crystals

With the development of science research, nanometer scale materials have recently attracted a lot of research interests and developed very rapidly. Nanometer scale materials have unique properties, such as force, electricity, light, magnetism and heat effect due to their superficial effect, bulk effect, quantum dimension effect and macrocosmic quantum tube effect, especially nanometer scale rare earth oxide such as neodymium oxide. Here, we report preparation of the nanometer-scale iron oxide and rare earth oxide particles via an easy thermo-decomposition method of their complexes. The complexes are obtained by reaction of their corresponding nitrate with o-nitro-benzoic acid. The characterization of the complexes and oxide particles are presented.(1) Nanometer-scaleα-Fe₂O₃ particles (10～45 nm) have been synthesized by the thermo-decomposition of a new Fe³⁺ complexes taking o-nitro-benzoic acid as ligand. Structure and properties of the Fe³⁺ complexes have been confirmed by XRD, FT-IR and DSC-TGA. And theα-Fe₂O₃ powders have been characterized by XRD, TEM, VSM and BET. Theα-Fe₂O₃ powders exhibit a specific surface area of 65.44 m²Â·g^-1. Control over the particle size, surface area, yield, and state of agglomeration could be achieved through variation of the experimental conditions.The nanometer-scale Nd₂O₃ particles (20～40 nm) have been synthesized by the thermo-decomposition of a new Nd³⁺ complexes taking o-nitro-benzoic acid as ligand. Structure and properties of the Nd³⁺ complexes have been confirmed by XRD, FT-IR and TGA. The Nd₂O₃ powders have been characterized by XRD and TEM.(2) [Nd(o-NO₂-C₆H₄COO)₃(DMF)₂]₂ and [Ln(o-NO₂-C₆H₄COO)₃(DMF)₂]₂ (Ln=Ce, Sm) are synthesized, and the crystal structure of the complexes is characterized by the methods of FT-IR, ¹H NMR, UV, elemental analysis, fluorescent emission spectra and X-ray single crystal diffraction.The first complex resides on an inversion center. The results show that the complex crystallizes in a triclinic system, space group P-1 with cell parameters a=1.18652(12) nm, b=1.24784(13) nm, c=1.29958(13) nm,α=64.220(1)°,β=66.306(1)°,γ=71.825(1)°, V=1.5645(3) nm³, D_c=2.167 mg·m^-1, Z=2,μ=3.415 mm^-1, F(000)= 986. Each Nd (â…¢) atom is bridged by four o-nitrobenzoates and chelated by one o-nitrobenzoate. The Nd (â…¢) atom is eight-coordinated by six oxygen atoms from five o-nitrobenzoates and two oxygen atoms from two DMF molecules. Hydrogen bonds and aromaticπ…πstacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence.The second complex also resides on an inversion center. The results show that the complex crystallizes in a triclinic system, space group P-1 with cell parameters a=1.18284(6) nm, b=1.25082(7) nm, c=1.30203(7) nm,α=63.965(10)°,β=66.390(10)°,γ=71.738(10)°, V=1.5637 (14) nm³, D_c=1.688 mg·m^-1, Z=2,μ=1.954 mm^-1, F(000)=794. Each Ln (â…¢) atom is bridged by four o-nitrobenzoates and chelated by one o-nitrobenzoate. The Ln (â…¢) atom is eight-coordinated by six oxygen atoms from five o-nitrobenzoates and two oxygen atoms from two DMF molecules. Hydrogen bonds and aromaticπ…πstacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence.