Benzene-1,3,5-tricarboxylate-bridged Double-layered Nickel(ll) Complex with Ferromagnetically Coupled Ni3 Units

• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2008,（8）
• 页码范围: 1527-1531
• 页数: 5页
• 语种: 英文

摘要

The reaction of benzene-1,3,5-tricarboxylic acid (H3BTC) with NiCO3 under hydrothermal conditions afforded a new 2D complex Ni3(BTC)2(μ-H2O)2·6H2O, which possesses an infinite double-layered structure. The layer is comprised of syn-syn carboxylate- and aqua oxygen-bridged Ni3 units that are connected further by BTC3-. Ferro-magnetic exchange interaction is operative between the Ni2+ ions, experimentally showing the propagation of fer-romagnetic coupling through the syn-syn carboxylate bridges because the magnetic exchange through the aqua bridges [Ni-O-Ni bond angle= 122.8(3)°] is antiferromagnetic. On the basis of the present results and the previ-ous reports on syn-syn carboxylate-bridged Ni(Ⅱ) complexes, it was found that the coplanarity of Ni-O-C-O-Ni dominated the magnetism. The planar arrangement of Ni-O-C-O-Ni gives rise to strong antiferromagnetic coupling, whereas the deviation from planarity weakens the antiferromagnetic coupling, possibly resulting in weak ferromagnetic coupling. Therefore, similarly to the mixed ligand-bridged Cu(Ⅱ) dimer the orbital complementary effect (OCE) is also operative in the aqua-/carboxylate-bridged Ni(Ⅱ) dimer.