2 - Methoxy-1 ,10 - Phenanthroline And 2 - (1,2,4-triazole) And 1,10 - Phenanthroline As Ligand Complexes Synthesis And Properties Of,

For more than three decades, the study of magnetic properties for complexes has been one of advanced disciplines in magnetic materials. A large number of multi-nuclear complexes have been synthesized and for these complexes the spin-carriers were linked by mono-atom or multi-atoms bridge ligands, and only a limited complexes deal with spin-carriers being connected by intermolecular force. Based on the study on these complexes some factors that dominate magnetic coupling properties have been understood. But it is far from to understanding thoroughly the relevant magnetic coupling mechanism and no ideal molecule-based ferromagnet has been synthesized to date. Therefore, it is very important in both the theory and the experiment area to design and synthesize new complexes, especially for the multi-nuclear complexes that the spin-carriers were linked by intermolecular force. Based on the concept mentioned above the six novel complexes have been designed and prepared, in which it includes three complexes with 2-methoxy-1,10-phenanthroline as one of terminal ligand, namely, the tetra-nuclear Cu(II) complex [Cu4(μ-OH)_<sub>2(μ-N₃)_<sub>2(H₂O)_<sub>2(Phen-OCH₃)₄](ClO₄)4 (1) with hydroxyl anion and azide anion as mixed bridge ligand and 2-methoxy-1,10-phenanthroline as terminal ligand; binuclear Cu(II) complex [Cu_<sub>2(μ-Cl)_<sub>2(Phen-OCH₃)(Cl)₂] (2) with two chlorido anions as bridge ligand and another two chlorido anions and 2-methoxy-1,10-phenanthroline as capped ligands; mono-nuclear Mn(II) complex [Mn(Phen-OCH₃)_<sub>2(HOCH₃)(NCS)](ClO₄) (3) with 2-methoxy-1,10 -phenanthroline, thiocyanate anion and methanol as terminal ligand. Another three novel complexes involve the mono-nuclear Cu(II) complex [Cu(TP)₂]?2BF4?CH₃CH₂OH (TP = 2-(1H-1,2,4-triazol-1-yl)-1,10- phenanthroline) (4) with 2-(1H-1,2,4-triazol-1-yl)-1,10-phenanthroline as terminal ligand; the mono-nuclear Cu(II) complex [Cu(Phen-OCH₂CH₃)_<sub>2(N₃)]2H₂O (5) with 2-ethoxyl-1,10-phenanthroline and azide anion as terminal ligands; mono-nuclear Cd(II) complex [Cd(DPP)(OON)OHCH₃]ClO₄ (DPP = 2,9-bis(3,5-dimethyl-1H-pyrazol-yl-1)-1,10-phenanthroline)(6) with 2,9-bis(3,5- dimethyl-1H-pyrazol-yl-1)-1,10- phenanthroline, nitrite anion and methanol as terminal ligands.For the complexes the infrared spectrum characterization was performed and their crystal structures determined with X-ray crystallography. The theoretical calculations were performed on complex (1) and based on the data of the calculations it is known that the magnetic coupling pathway of both hydroxyl anion and azide anion as bridge ligands results in strong ferromagnetic interaction, whereas another three magnetic coupling pathways only lead to the weak ferromagnetic coupling and the weak anti-ferromagnetic coupling, respectively. The variable-temperature magnetic susceptibility was measured for complex (3) and the fitting for the variable-temperature magnetic susceptibility reveals that there are a medium ferromagnetic interaction and a weak anti-ferromagnetic interaction among the adjacent Cu(II) ions. The theoretical calculations indicate that the magnetic coupling pathway of the chlorido anion as bridging ligand brings about medium ferromagnetic coupling, theÏ€?Ï€stacking pathway results in a weak ferromagnetic interaction. The other three magnetic coupling pathways from the Cl???H short contact lead to the weak anti-ferromagnetic interaction. Obviously, the ferromagnetic coupling from the experimental fitting seems from the cooperation of the magnetic coupling pathway of the chlorido anions as bridging ligand and theÏ€?Ï€stacking pathway; whereas the anti-ferromagnetic coupling of the fitting may arise from the cooperation of the three magnetic coupling pathways of the Cl???H short contact .The theoretical calculations accord basically with the experimental fitting. The theoretical calculations also gave the information of the magnetic coupling properties dealing with the relevant coupling pathways in complex (3), complex (4) and complex (5), and the correlation between the relevant structural factors and the magnetic coupling properties were studied and the some interesting information was obtained.The obtained results from the dissertation will not only benefit to further understanding the magnetic coupling properties of the complexes with chlorido anion as bridge ligand and the complexes with anzide anion and hydroxyl anion as mixed bridge ligands and but also it will benefit to understand the magnetic coupling properties arisen from the intermolecular force. At the same time, the dissertation may benefit to design and synthesize the ideal molecule-based ferromagnets.