Synthesis, Structures And Properties Of Complexes Based On Oxime Ligands

Nanoscale metal clusters have drawn more and more attention not only due to their fascinating structures, but also the potential applications in molecular magnets, nano catalyst, nanophotonics and nano electronic devices. As a kind of chelating ligand, aldehydeoxime possessing N and O donors, are widely used in coordination and analytical chemistry, as well as in biological fields. Various aldehydeoxime ligands, including pyridine oximes and salicylaldoxime, show strong coordination ability in the formation of various polynuclear complexes.The synthesis, structures, magnetic properties, luminescence properties and catalytic properties of transition metal complexes based on oxime ligands were reported in this thesis. Six coordination complexes were obtained by using solvothermal method. The magnetic properties, luminescent properties or the catalytic activities of these complexes were investigated. The results were briefly described as follows.1. By employing 3-methyloxysalicylaldoxime(H2MeOsalox) as the ligand, one coordination complex, [CoII9CoIII3(MeOsalox)6(OAc)15(H2O)6]·2MeCN·2H2O(1),(H2MeOsalox = 3-methyloxysalicylaldoxime) was synthesized under solvothermal condition, and characterized by IR, elemental analyses(EA), single-crystal X-ray diffraction, and powder XRD.Variable temperature(2.0–300 K) magnetic studies for the wheel-like complex 1 indicated weak antiferromagnetic exchange interactions. Complex 1 can act as catalyst in methylene blue degradation reaction.2. Five complexes of formulas [Gd2Mn(MeOsalox)2(NO3)2(OAc)2(H2O)]n(2), [Gd4Cd2(MeOsalox)4(NO3)4(OAc)4(H2O)2(MeOH)2]·MeOH(3), [Nd2Mn(MeOsalox)2-(NO3)2(OAc)2(H2O)(EtOH)]n(4), Nd4Zn4(HMeOsalox)4(MeOsalox)4(NO3)6(OAc)2-(H2O)4(EtOH)2(5), Sm2Mn2(HMeOsalox)2(MeOsalox)2(OAc)4(H2O)2(6),(H2MeOsalox = 3-methyloxysalicylaldoxime) were synthesized via the reaction of 3-methyloxysalicylaldoxime with different transition and rare-earth metal salts under solvthemal conditions. By the use of different transition metal salts, the structures of complexes varies. The employment of Mn(OAc)2 gave a complex with a chain structure. When Zn(OAc)2 was used as the transition metal salt, respectively, new coordination complexe which contains eight metal cores was generated. The reaction solvent also affected the structures, complex 3 was obtained under the condition of using methanol as solvent.Variable-temperature dc magnetic susceptibility data were collected on powdered microcrystalline samples of complex 2 in the 300-2.0 K range under an applied field of 1 kOe and the results indicate that the exchange between the metal ions of complex 2 is ferromagnetic in nature. The luminescence properties of complexes 3,4 and 5 were studied, and they all show weak emission in solid state at room temperature. Compared with ligand, the emission wavelength of these complexes were red-shifted.