Polynuclear Ni(II)/Co(II)/Mn(II) Complexes Based on Terphenyl鈥揟etracarboxylic Acid Ligand: Crystal Structures and Research of Magnetic Properties

详细信息    查看全文

• 作者：Lin Zhang ; Lu Liu ; Chao Huang ; Xiao Han ; Li鈥檃n Guo ; Hong Xu ; Hongwei Hou ; Yaoting Fan
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：July 1, 2015
• 年：2015
• 卷：15
• 期：7
• 页码：3426-3434
• 全文大小：578K
• ISSN：1528-7505

文摘

By the solvothermal reactions of a [1,1鈥?3鈥?1鈥?terphenyl]-3,3鈥?5,5鈥?tetracarboxylic acid (H₄tpta) with transition metal ions, three novel polymeric complexes, namely {[Ni₂(tpta)(H₂O)₃]路H₂O}_n (1), {[Co₄(tpta)₂(4,4鈥?bpy)(H₂O)₃]路3H₂O}_n (2), and {[Mn₂(tpta)(H₂O)₂]路2H₂O}_n (3), have been isolated. The heterometallic clusters of these polymeric complexes are dimeric and tetrameric, respectively. 1 is composed of dimeric paddle wheel Ni(II) units to generate a 2D structure. In complexes 2 and 3, metal ions form tetrameric units that extend via all dimensions to give 3D structures with the Schl盲fli symbol of (4³)(4³)(4⁶路6¹⁸路8⁴) and (4⁶)(4¹²路5³路6⁹路7⁴), respectively. The results of variable temperature magnetization measurements (蠂_mT-T and 蠂_m^鈥?-T) show that complexes 1 and 2 display unusual ferromagnetic coupling via the M鈥揙鈥揅鈥揙鈥揗 bridges, while complex 3 shows predominantly antiferromagnetic behavior. The M(H) curve of 1 does not saturate until the highest field of 80 kOe, indicating the significant magnetic anisotropy in this complex system, whereas the final saturation value of 2.79 N尾 for 2 manifests the existence of typically paramagnetic property and the absence of long-range magnetic ordering. The dynamic magnetization experiments have been also carried out to further explore the magnetic behaviors of 1 and 2. There are no frequency dependences in the dynamic magnetization experiments, suggesting the absence of slow magnetic relaxation of these two complexes.