Study on Preperation, Characterization and Methodology of Salen-type Metal Complexes and Rare Earth Nanometer Oxide

Abstract: Salen and its derivatives are a kind of important ligands, which are prepared by the condensation of aldehydes or ketones with amines or hydrazines. It is signality to study Salen and their complexes due to their easy preparation, well coordinated capability to the transition metal ions, as well as the effectively pharmacology and physiology.The study on this kind of compound has been the hotspot of the coordination chemistry field for many years.In order to investigate the mechanism, construction and stability of the physiology and pharmacology, it is very important to study the coordination between the Salen and the metal ions. To study the designation, preparation, magnetism and biological activity of the complexes bearing more than one paramagnetic center is not only useful to illustrate the electron transfer in the life and the active part of the metal loenzyme, but also to illustrate the relationships between the magnetism and the structures, furthermore, to bring out the theories in the designation of novel magnetic materials.Bis(salicyladimine) derivatives are good tetradentate N_2O_2-donating ligands with largeπ-conjugating system. The N-donating ligands have been applied diffusely in synthesis of transition metal complexes for their better coordination capability, so we studied their special properties such as characterizations in light, electricity, magnetism, catalysis and biochemistry. The applied foreground of these compomds will be extensive in the field of catalysis, bioactivity and material etc. So, preparing new Salen complexes and studying their properties and applications are of great importance to the development of coordination chemistry.In this paper, there kinds of novel Salen ligands and its derivatives which are 4,4'-dichloro-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol(H_2L~1), 4,4'-dichloro-2,2'-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol(H_2L~2), 4,4'-dichloro-2,2'-[(1 ,4-butylene)dioxybis(nitrilomethylidyne)]diphenol(H_2L~3), have been synthesized make use of three kinds of novel diamine (1,2-bis(aminooxy)ethane, 1,3-bis(aminooxy)propane and 1,4-bis(aminoxy)-butane). The complexes have been synthesized by the reaction of the ligands with transition metal acetate in this article. The ligands and their complexes were characterized by elementary analysis, IR spectra, ~1H-NMR, TG-DTA analysis, molar conductance analysis and X-ray single crystal diffraction Structures of the compounds have been determined by X-ray single crystal diffraction.There single crystals of the ligands and their complexes have been obtained by nature evaporation or gaseous diffusion method, which are H_2L~1 ligand, H_2L~2 ligand, H_2L~3 ligand, Cu(Ⅱ) acetate monohydrate complex with H_2L~1, Co(Ⅱ) acetate tetrahydrate complex with H_2L~1, Co(Ⅱ) acetate tetrahydrate complex with H_2L~2 (matched by methanol and ethanol respectively) and Ni(Ⅱ) tetrahydrate complex with H_2L~2 and their space structures which are maked certain by X-ray single crystal diffractionRare earth nanometer oxide is one of important rare earth compound, which is a new technology material, can be used to irradiance material, ultraviolet absorb material, the rag wheel of glass, catalyst, electron chinaware etc. Moreover, the rare earth nanometer oxide put up more ascendant capability. They can incarnate a great deal of novel character and application when they are made to be nanometer oxide.Solid-state reaction and nitrate-glycine solution combustion method were introduced in this paper, and preparation technics of a series of rare earth oxide nanometer powder were discussed systemicly. The average particle size and the shape of sample were characterized by TG-DTA , TEM and XRD. Compared with each other on the base of technics and economy aspects, we can put forward a feasible technics parameter in magnify middle experimentation.Nanometer CeO_2 , La_2O_3, Nd_2O_3 powders were prepared by solid-state reaction: In appropriate technologic conditions, RE formate as a precursor, Nano-rare earth oxides have been prepared by the thermal decomposition. The process parameters is: n (ceria) :n(HCOOH)=1:3.5; with cerium carbonate dispersant A mass ratio (200 :1); drying temperature is 90℃; drying time is 2 hours. The system can be smaller than 15 nm in diameter CeO_2 nanocrystalline after powder roasted at 525℃for about 30min; Thermal analysis shows that: Ce(COOH)_3 into CeO_2 one-step in the process is completed, in Ce(COOH)_3 to the complete transformation of CeO_2 in the vicinity of 280℃.Nanometer Sm_2O_3, Eu_2O_3 and Y_2O_3 powders were prepared by nitrate-glycine solution combustion method: a certain amount of nitrate RE and glycine (at 1:1 molar ratio) be mixed in crucible, A reaction mixture can be gained by adding a certain amount of water. Put the solution into the muffle whose temperature is 100℃which was warm-up advance, and then keeps for 10 min. Heat up sequentially till the temperature of temperature the muffle reaches 520℃. That is a product of goal at half an hour to respond fully. The crystal shape of the sample is half-baked under 250℃; when the temperature above 350℃, nano spathic power can be gained; the preferable nano spathic power can gained at 520℃.Analysis of TEM illustrates that: the cerium dioxide nano-powder has a uniform measurement and regular spherical shape prepared with process above. Crystal grain size measured by TEM photos accords substantially with the size calculated by XRD experiment…
Key words: Salen-type Ligand; Nano; Rare earth oxide; Transition Metal Complexes; Preperation; Characterization; Methodology

This entry was posted in Master Thesis. Bookmark the permalink.